Long-billed Curlew (Numenius americanus): COSEWIC assessment and status report 2024

Official title: COSEWIC assessment and status report on the Long-billed Curlew (Numenius americanus) in Canada

Threatened

2024

COSEWIC assessment summary

Assessment summary - May 2024

Common name: Long-billed Curlew

Scientific name: Numenius americanus

Status: Threatened

Reason for designation: This large, long-billed shorebird breeds in the grasslands and prairies of western Canada from central British Columbia to Saskatchewan, and winters in the southern US and Mexico. It formerly bred in Manitoba, but breeding has not been observed there since the mid-1980s. Although declines have been documented in Canada since the 1970s, trends have recently become more negative, with a decline of approximately 50% over the last 20 years (3 generations), a likely decrease in the area occupied by breeding birds since the last status report in 2011, and declining quality of habitat. Key threats include droughts and extreme events induced by climate change; related changes to water management on the wintering grounds; impacts of pesticides on insect prey; and conversion and fragmentation of grasslands and suitable agricultural habitat by energy development, urban sprawl, and rural development on breeding and wintering grounds. As a relatively long-lived species with low reproductive output, its population is limited to slow growth even under favourable conditions.

Occurrence: British Columbia, Alberta, Saskatchewan

Status history: Designated Special Concern in April 1992. Status re-examined and confirmed in November 2002 and May 2011. Status re-examined and designated Threatened in May 2024.

COSEWIC executive summary

Long-billed Curlew

Numenius americanus

Wildlife species description and significance

Long-billed Curlew (Numenius americanus) is a very large, mottled-brown sandpiper with an extremely long, decurved bill and cinnamon underwing. Canadian birds belong to the subspecies N. a. parvus.

Aboriginal (Indigenous) knowledge

All species are significant and are interconnected and interrelated. There is no species-specific ATK in the report.

Distribution

Long-billed Curlew breeds in the grassland regions of North America from southern Canada to northern Texas, wintering from central California to southern Florida and Mexico, and irregularly into Central America. In Canada, Long-billed Curlew breeds in British Columbia, Alberta and Saskatchewan, and bred in Manitoba until the mid-1980s. British Columbia and the Prairies are recognized by some sources as having distinct subpopulations but there is no evidence to suggest the presence of more than one designatable unit in Canada.

Habitat

Long-billed Curlew prefers extensive, flat areas of short native grassland for breeding, but also uses some agricultural areas for feeding, nesting and rearing young. During migration and in winter, the species frequents various types of shoreline and wetland habitats.

Biology

Long-billed Curlew is migratory and generally arrives in Canada in March (British Columbia) or April (Alberta and Saskatchewan). Clutch size is usually four eggs. The incubation period is 27 to 30 days, with incubation shared by both sexes. Generation length is estimated to be 6.7 years. Eggs are vulnerable to predation by mammals and birds, as well as to trampling by livestock. After the chicks have hatched, the adults disperse from the breeding territory. Females depart before males, followed by immature birds. Chicks have a high mortality rate, succumbing to heat stress, starvation, and predation by hawks, corvids and weasels. Curlews feed primarily on grasshoppers and beetles on the breeding grounds. Failed breeders may leave Canada by late June, with most others departing by the end of August.

Population sizes and trends

The most recent population estimate for Canada in 2023—a range of 139,795 to 147,783 mature individuals— was derived from the modelling of remotely sensed data. Although this estimate is much higher than previous estimates for Canada, it reflects a change in methods rather than a population increase. The Breeding Bird Survey (BBS) indicates a substantial steady decrease in the size of the Canadian population beginning around 2004, amounting to a cumulative loss of about 51% over the past three generations (20 years). The decline has been greatest in Alberta, which supports the largest portion of the Canadian population. A targeted survey of the much smaller British Columbia population in 2022 did not show an appreciable population change compared to a survey conducted in 2005. Trends in U.S. states near the species’ Canadian range vary from decreasing to strongly increasing; however, rescue from the U.S. is thought to be unlikely, as immigrants to Canada would face suboptimal conditions in areas where their habitat has been lost or degraded.

Threats

Current and anticipated threats to Long-billed Curlew include energy development; droughts and temperature extremes induced by climate change, including related changes to water management; conversion of grasslands to annual and perennial crops, sometimes associated with unsustainable and more intensive agricultural practices that reduce habitat quality; fire suppression resulting in forest/shrubland encroachment; urban sprawl and rural development in both breeding and wintering habitat; impacts of pesticides, resulting in declines in insect prey; habitat fragmentation, which facilitates increased predation; and proliferation of invasive, non-native plant species, especially Leafy Spurge and knapweeds.

Additional threats to the species include inappropriate grazing management (that is, absence of grazing or high-intensity, frequent or prolonged cattle grazing that reduces habitat quality); direct mortality due to the use of agricultural pesticides; hunting and poaching on the wintering grounds and during migration; disturbance or harm caused by industrial activities; and accidental mortality caused by collisions with wind towers or vehicles. Given the recent and accelerating decline in the species’ population, the impacts of threats may be increasing. The overall threat impact is assessed as Medium–High.

Protection, status and recovery activities

Long-billed Curlew was listed as Special Concern in Canada on Schedule 1 of the Species at Risk Act in 2005. COSEWIC confirmed this status in May 2011 and, most recently, reassessed this species as Threatened in May 2024. The species and its nests are protected under the Migratory Birds Convention Act, 1994 in Canada and equivalent legislation in the United States. Long-billed Curlew is yellow-listed in British Columbia (since 2022), and is considered a species of Special Concern in Alberta. Less than 1% of Long-billed Curlew breeding habitat in Canada is formally protected.

In the U.S., Long-billed Curlew has no status under the Endangered Species Act, but has been designated a Bird of Conservation Concern by the U.S. Fish and Wildlife Service nationally, in five U.S. Fish and Wildlife Service regions, and in several Bird Conservation Regions. Long-billed Curlew has also been designated a species of concern in several U.S. states.

NatureServe considers the species Apparently Secure globally and in the U.S., and Vulnerable in Canada. NatureServe ranks the species Vulnerable in Alberta and Saskatchewan, Apparently Secure in British Columbia, and Presumed Extirpated in Manitoba.

Technical summary

Numenius americanus

Long-billed Curlew

Courlis à long bec

ayaheeyáa (Tlingit)

Range of occurrence in Canada: British Columbia, Alberta, Saskatchewan

Demographic information

Generation time (usually average age of parents in the population)

Approximately 6.7 years

Based on Bird et al. 2020

Is there an [observed, inferred, or projected] continuing decline in number of mature individuals?

Yes

Based on BBS data for Canada

[Observed, estimated, or projected] percent of continuing decline in total number of mature individuals within 3 years [or 1 generation; whichever is longer up to a maximum of 100 years]

Unknown

Observed, estimated, or projected percent of continuing decline in total number of mature individuals within [5 years or 2 generations, whichever is longer up to a maximum of 100 years].

2-generation (approximately 13 years) rate of decline not calculated. 10-year decline is

36.2% (4.40%/year).

Based on short-term BBS trend in Canada (2011 to 2021)

Trends derived from eBird data for the 10-year period of 2012 to 2022 are negative, but non-significant (-0.4%; 80% CI, -6% to 11.6%).

[Observed, estimated, inferred, or suspected] percent reduction in total number of mature individuals over the last [10 years, or 3 generations, whichever is longer up to a maximum of 100 years].

-51.0% (95% CI,

-6.7 to -31.7) over 20 years/3 generations, or ‑3.50%/year (95% CI,

-5.26 to -1.84)

Based on 3-generation BBS trend in Canada during 2001 to 2021 period; decline observed particularly since 2005

[Projected, inferred, or suspected] percent reduction in total number of mature individuals over the next [10 years, or 3 generations, up to a maximum of 100 years].

Projected continuing decline at similar rates to those in the past, or 3 to 70% based on assessed High–Medium threat impact

Likely to continue declining based on recent trends and multiple ongoing and increasing threats

[Observed, estimated, inferred, projected, or suspected] percent [reduction or increase] in total number of mature individuals over any period [10 years, or 3 generations, whichever is longer up to a maximum of 100 years], including both the past and the future.

Inferred and projected reduction of 51% based on BBS trend over last 3 generations and continuation of threats, or 3 to 70% based on assessed High–Medium threat impact

Likely to continue declining based on recent trends and multiple ongoing threats

Are the causes of the decline clearly reversible?

Unknown

Are the causes of the decline clearly understood?

In part

Many threats recognized, although their relative significance remains poorly understood

Have the causes of the decline ceased?

No

Are there extreme fluctuations in number of mature individuals?

No

Extent and occupancy information

Estimated extent of occurrence (EOO)

907,483 km²

Area of the minimum convex polygon bounding all the 3,803 element occurrences in the NatureCounts database (NatureCounts 2024) in the breeding range from 1 April to 31 July 2000 to 2023 (approximately 3 generations)

Index of area of occupancy (IAO), reported as 2x2 km grid value.

15,212 km²

Calculated by summing the area of 2 km x 2 km grid squares that encompass all 3,803 element occurrence records (see Box 10, above)

Is the population “severely fragmented” that is, is >50% of individuals or >50% of the total area “occupied” (as a proxy for number of individuals) in habitat patches that are both (a) smaller than would be required to support a viable population, and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse?

1. No
2. No

The species has a strong ability to disperse, and the majority of the habitat used by the population is not separated by large distances.

Number of “locations” (use plausible range to reflect uncertainty if appropriate)

> 100

Actual number of locations unclear, but at least in the hundreds given that the most pervasive threats appear to be local in nature

Is there an [observed, inferred, or projected] continuing decline in extent of occurrence?

No

Although the EOO calculated in this report (907,483 km²) is greater than that in the previous assessments in 2002 and 2011 (530,000 km²), this can be explained by (i) a few relative outliers in eastern Saskatchewan; (ii) the slight expansion of the breeding range northward in British Columbia; and (iii) the effect of the increased observer effort in recent years and the widespread use of eBird. Overall, the EOO is not believed to have increased or declined appreciably.

Is there an [observed, inferred, or projected] continuing decline in area of occupancy?

Yes

Observed decrease based on the element occurrence records collected in this report; the IAO value calculated in this report (15,212 km²) is lower than that in the 2002 assessment (est. 20,000 km²) and presumably the 2011 assessment, where the IAO was provided as “> 2,000 km²” with the note that “there is no evidence to suggest a change in … IAO since the last status report in 2002.” Although the methods to determine the 2002 IAO would have differed from the current one, the 25% difference between the two values is sizable. A decline in IAO is also projected based on climate-induced habitat loss.

Is there an [observed, inferred, or projected] continuing decline in number of subpopulations?

No

Is there an [observed, inferred, or projected] continuing decline in number of “locations”?

Unknown

Difficult to evaluate given the uncertainty in the number of locations

Is there an [observed, inferred, or projected] continuing decline in [area, extent and/or quality of] habitat?

Yes, inferred and projected

Between 2011 and 2017, losses of native and planted grasslands in Canada were estimated at 1.32%, which represents a total loss of roughly 200,000 ha. These losses are ongoing.

Are there extreme fluctuations in number of subpopulations?

No

Are there extreme fluctuations in number of “locations”?

No

Are there extreme fluctuations in extent of occurrence?

No

Are there extreme fluctuations in index of area of occupancy?

No

Number of mature individuals (in each subpopulation)

Subpopulations

N Mature Individuals

(give plausible ranges)

Notes on individual estimates

British Columbia

2,693 to 10,681

7,436

Based on estimate made in 2022 (Bradley and Torrenta 2022).

Jones et al. (2008), Andres et al. (2012)

Alberta, Saskatchewan

137,102 (90% CI, 113,298 to 169,794)

35,420

Based on estimate made in 2023 (Robinson unpubl. data)

Jones et al. (2008), Andres et al. (2012)

Total in Canada

139,795 to 147,783

approximately 43,000

Sum of provincial estimates above

Sum of survey-based estimates above summarized in Andres et al. (2012)

Quantitative analysis

Is the probability of extinction in the wild at least [20% within 20 years or 5 generations whichever is longer up to a maximum of 100 years, or 10% within 100 years]?

Unknown

Analysis not conducted

Threats and limiting factors

Was a threats calculator completed for this species?

Yes (see Appendix 1)

Overall threat impact: High–Medium

Key threats were identified as:

• IUCN 1, Residential and Commercial Development (Low threat impact, based on loss of habitat)
• IUCN 2, Agriculture and Aquaculture (Low threat impact, based primarily on loss of grassland habitat, and unsustainable agricultural practices)
• IUCN 3, Energy Production and Mining (Low threat impact, based on habitat loss and fragmentation from oil and gas drilling)
• IUCN 5, Biological Resource Use (Low threat impact, based on hunting during migration and on the wintering grounds)
• IUCN 7, Natural System Modifications (Low threat impact, primarily based on fire suppression, reduced prey availability resulting from pesticide use, and changes to water management on the wintering grounds)
• IUCN 8, Invasive and Other Problematic Species, Genes and Diseases (Low threat impact, based primarily on invasive plant species and increasing predator pressure)
• IUCN 9, Pollution (Low threat impact, based on exposure to agricultural pesticides)
• IUCN 11, Climate Change and Severe Weather (Low threat impact, based on implications of drought, increased severe weather and increasing sea levels on wintering grounds)

Threats of Unknown impact include: IUCN 4.2 (that is, collisions with utility lines); IUCN 8.1 (that is, invasive non-native species); IUCN 8.5 (that is, avian influenza H5N1); IUCN 9.2 (that is, contaminants in tailings and wastewater ponds); IUCN 9.6 (that is, noise pollution on the breeding grounds); and IUCN 11.1 (that is, habitat shifting and alteration due to climate change).

What additional limiting factors are relevant?

• Low reproductive output (single clutch annually; relatively small clutch size; delayed sexual maturity, especially in females; low incidence of re-nesting)

Rescue effect (natural immigration from outside Canada)

Status of outside population(s) most likely to provide immigrants to Canada.

Some increasing and others decreasing

Populations in Montana are increasing and may provide immigrants to Canada, while populations in other states may be decreasing.

Is immigration known or possible?

Yes

Immigration is likely, although undocumented.

Would immigrants be adapted to survive in Canada?

Yes

No reason to think that immigrants could not survive in Canada, but they would be subject to the same threats and habitat loss as Canadian birds.

Is there sufficient habitat for immigrants in Canada?

Yes

Are conditions deteriorating in Canada?

Yes

Are conditions for the source (that is, outside) population deteriorating?

Unknown

Is the Canadian population considered to be a sink?

Unknown

Is rescue from outside populations likely, such that it could lead to a change in status?

Unlikely

Rescue is possible, as habitat remains in Canada, immigrants are likely adapted to survive, and source populations in some neighbouring U.S. states appear either stable or are increasing. However, strong declines in Alberta, where the majority of the Canadian population occurs, suggests that immigrants would face suboptimal conditions there.

Occurrence Data Sensitivity

Could release of certain occurrence data result in increased harm to the Wildlife Species or its habitat?

No

Some occurrence data from Alberta have been used in coarse mapping products only, to prevent possible harmful implications for the species or its habitat.

Status history

COSEWIC

Designated Special Concern in April 1992. Status re-examined and confirmed in November 2002 and May 2011. Status re-examined and species designated Threatened in May 2024.

Status and reasons for designation

Status: Threatened

Alpha-numeric codes: A2bc+4bc

Reason for change of status: Iii; IIi,ii,iii,vii,viii,xi; IIIi; IViii

Reasons for designation: This large, long-billed shorebird breeds in the grasslands and prairies of western Canada from central British Columbia to Saskatchewan, and winters in the southern US and Mexico. It formerly bred in Manitoba, but breeding has not been observed there since the mid-1980s. Although declines have been documented in Canada since the 1970s, trends have recently become more negative, with a decline of approximately 50% over the last 20 years (3 generations), a likely decrease in the area occupied by breeding birds since the last status report in 2011, and declining quality of habitat. Key threats include droughts and extreme events induced by climate change; related changes to water management on the wintering grounds; impacts of pesticides on insect prey; and conversion and fragmentation of grasslands and suitable agricultural habitat by energy development, urban sprawl, and rural development on breeding and wintering grounds. As a relatively long-lived species with low reproductive output, its population is limited to slow growth even under favourable conditions.

Applicability of criteria

A: Decline in total number of mature individuals

Meets Threatened, A2bc+4bc. There is an estimated reduction in the total number of mature individuals of approximately 50% over the past 3 generations (20 years), based on Breeding Bird Survey data (A2b). Continuing declines are also inferred and projected in the IAO and habitat quality.

B: Small distribution range and decline or fluctuation

Not applicable. EOO of 907,483 km² and IAO of 15,212 km² exceed thresholds for Threatened.

C: Small and declining number of mature individuals

Not applicable. The estimated number of mature individuals exceeds thresholds for Threatened.

D: Very small or restricted population

Not applicable. The estimated number of mature individuals exceeds thresholds for D1, and population is not vulnerable to rapid and substantial decline.

E: Quantitative analysis

Not applicable. Analysis not conducted.

Preface

Long-billed Curlew (Numenius americanus) was first assessed by COSEWIC in 1992 as Special Concern, and its status was re-examined and confirmed in November 2002 and May 2011. New data are limited with respect to population estimates. BBS data suggest a declining trend nationally, particularly since around 2005. A migration tracking study of birds breeding in British Columbia conducted in 2017 to 2021 revealed that the species overwinters primarily in the Central and Imperial valleys of California (Bradley unpubl. data). Migration routes and stopover sites also determined through the tracking study show the temporary use of wetlands and irrigated fields in the dry interior of eastern Washington, eastern Oregon and Nevada (Bradley unpubl. data). A single bird satellite-tagged in coastal Georgia in 2015 was tracked to Saskatchewan the following year (Carlisle unpubl. data). A management plan for the species in Canada was developed in 2013 and in Alberta (Alberta Conservation Management Plan) in 2010. New Wildlife Habitat Areas (WHAs) in British Columbia and Indigenous Protected and Conserved Areas (IPCAs) (across Canada) in the species’ range may have benefitted or may benefit the species, in addition to current protected areas.

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2024)

Wildlife species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special concern (SC)
(Note: Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.)

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at risk (NAR)
(Note: Formerly described as “Not In Any Category”, or “No Designation Required.”)

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data deficient (DD)
(Note: Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” [insufficient scientific information on which to base a designation] prior to 1994. Definition of the [DD] category revised in 2006.)

A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial support to the COSEWIC Secretariat.

Wildlife species description and significance

Name and classification

Current classification:

Class: Aves

Order: Charadriiformes

Family: Scolopacidae

Genus: Numenius

Species: N. americanus

Subspecies in Canada (if applicable):

The American Ornithological Society recognizes two subspecies, based on Bishop (1910): Numenius americanus americanus and N. a. parvus. Only N. a. parvus, the smaller of the subspecies, occurs in Canada (Dugger and Dugger 2020).

Taxonomic changes since previous report (for reassessments): None

Common names:

English: Long-billed Curlew

French: Courlis à long bec

Indigenous: ayaheeyáa (Tlingit)

Other name(s): Sicklebill, Sickle-billed Curlew, Candlestick bird

Synonyms and notes:

The American Ornithological Society places Long-billed Curlew in the subfamily Scolopacinae and the tribe Numeniini (Chesser et al. 2021). Phylogenetic analyses of morphological characters suggest Numenius is monophyletic and a sister taxon to Bartramia (for example, Upland Sandpiper; B. longicauda; Chu 1995). There is no documented evidence of hybridization.

Description of wildlife species

Long-billed Curlew is the largest of the North American shorebirds and one of the largest sandpipers in the world. The length of adult birds is 51 to 66 cm (Godfrey 1986). Adults weigh between 445 g and 951 g (Johnsgard 1981). The species’ most characteristic feature is its very long, down-curved bill, which can be up to 21 cm in length. Females are generally larger than males and have a noticeably longer bill (Allen 1980; Johnsgard 1981). The plumage is brownish on the upper parts and a lighter buff colour on the under parts, and is identical in both sexes. The Long-billed Curlew’s cinnamon wing linings help distinguish it from the shorter-billed and smaller Whimbrel (Numenius phaeopus). The down-curved bill distinguishes Long-billed Curlew from Marbled Godwit (Limosa haemastica), which has a straight or slightly upturned bill.

Long-billed Curlew has a variety of characteristic calls, including a loud curlee curlee, long-drawn-out whistles, and soft kerr kerr notes that are repeated during males’ courtship flights.

Designatable units

There is insufficient evidence to support the recognition of more than one designatable unit in Canada. Although there does not appear to be direct exchange between the two Canadian subpopulations identified in tracking studies (see Population Structure, below), no genetic research has been carried out to explore their differentiation, nor are there any apparent differences in morphology or behaviour.

Special significance

Long-billed Curlew holds special significance to the ranching community in Canada, and the attraction to the species by the public and naturalist community is strong.

Aboriginal (Indigenous) knowledge

Aboriginal Traditional Knowledge (ATK) is relationship-based. It involves information on ecological relationships between humans and their environment, including characteristics of species, habitats and locations. Laws and protocols for human relationships with the environment are passed on through teachings and stories, and Indigenous languages, and can be based on long-term observations. Place names provide information about harvesting areas, ecological processes, spiritual significance or the products of harvest. ATK can identify life history characteristics of a species or distinct differences between similar species.

Cultural significance to Indigenous peoples

There is no species-specific ATK in the report. However, Long-billed Curlew is important to Indigenous Peoples, who recognize the interrelationships of all species within the ecosystem.

Distribution

Global range

Long-billed Curlew is endemic to North America. It breeds in grassland regions from southern Canada to northern Texas and from eastern Washington to central Nebraska, and winters in the southern U.S. from central California, southern Arizona (rarely), southern Texas, southern Louisiana and coastal South Carolina south to southern Mexico, southern Florida, and, irregularly, to Central America as far south as Costa Rica (Figure 1; Fellows and Jones 2009; Dugger and Dugger 2020). Occasional winter records have been obtained in New Brunswick, Missouri, British Columbia, Washington, Oregon, Panama, Venezuela, French Guiana and the Greater Antilles (American Ornithologists’ Union 1983; De Smet 1992; Tostain et al. 1992). Both the breeding and wintering ranges of Long-billed Curlew have decreased significantly since the beginning of the 1900s, with approximately 30% of the original range lost (De Smet 1992; Fellows and Jones 2009); the original declines resulted from habitat loss and hunting (De Smet 1992). The species has been extirpated from the eastern part of its breeding range, including Manitoba, Michigan, Minnesota, Wisconsin, Illinois, Iowa, eastern Nebraska and eastern Kansas (De Smet 1992). Historically, Long-billed Curlew was a common to abundant winter resident along the Atlantic coast as far north as Newfoundland (De Smet 1992).

Figure 1. Breeding and wintering range of Long-billed Curlew (from De Smet 1992).

Canadian range

In British Columbia, the breeding range of Long-billed Curlew is primarily in the Southern Interior, including the Thompson-Okanagan Plateau and Chilcotin-Cariboo region north to the Quesnel area, from Prince George west to Vanderhoof and Burns Lake, in the Rocky Mountain Trench around McBride, and in the East Kootenay region north to Windermere (Campbell et al. 1990; Cannings 1999; Davidson and Mahony 2015). In the Prairies, the species’ range spans much of southern Alberta and southwestern Saskatchewan (Renaud 1980; Smith 1996; Federation of Alberta Naturalists 2007; Figure 2), although historically the species bred in southwestern Manitoba until the mid-1980s. The loss of birds in this locality represents a historical range contraction. Although results from recent habitat availability modelling suggest that birds continue to occur in Manitoba, only a single recent record has been obtained there, of a bird calling in June 2021 (Koes 2021; Poole pers. comm. 2024). Moreover, the Manitoba Breeding Bird Atlas (2010 to 2014) did not detect the species (see Data Sources, Methods, and Uncertainties and Abundance, below).

Figure 2. Element occurrences of Long-billed Curlew in Canada based on records entered in NatureCounts (2024) from 1 April to 31 July, 2000 to 2023. Map generated by D. Ethier, Birds Canada.

Population structure

In Canada, satellite-tracking data on 13 individuals (Bradley unpubl. data) shows no exchanges of individuals across the Rocky Mountains, suggesting that two breeding assemblages can be identified for management purposes, one in British Columbia and one in the Prairies (Alberta and Saskatchewan).

Extent of occurrence and area of occupancy

Current EOO

The current extent of occurrence (EOO) is approximately 907,483 km² in Canada, calculated using the minimum convex polygon bounding all 3,803 element occurrences entered in the NatureCounts database (NatureCounts 2024) from 1 April to 31 July, 2000 to 2023 (Figure 2).

Current IAO

The current index of area of occupancy (IAO) was calculated by summing the area of the 2 km x 2 km cells containing the element occurrences (1 April to 31 July, 2000 to 2023), totalling approximately 15,212 km².

Fluctuations and trends in distribution

The current EOO is higher than the previously reported value of 530,000 km² (COSEWIC 2002, 2011), which can be explained by (i) a few relative outliers in eastern Saskatchewan; (ii) a slight expansion of the breeding range northward in British Columbia; and (iii) the increased observer effort in recent years, including the widespread use of eBird (eBird 2022) for reporting observations. Overall, the EOO is not believed to have increased. The current IAO is lower than the 20,000 km² value reported in 2002 (COSEWIC 2002) and the IAO value implied in the 2011 status report (COSEWIC 2011; that document only reports an IAO of “> 2,000 km²”—that is, the cutoff value for a status of Threatened—and states that “there is no evidence to suggest a change in … IAO since the last status report in 2002”). Although the methods used to determine the 2002 IAO would have differed from the current one, the 25% difference between the two values is sizable; see Fluctuations and trends.

Biology and habitat use

The most comprehensive overview of the biology of Long-billed Curlew is available in the Birds of the World account (Dugger and Dugger 2020); only key details relevant to status determination are discussed in the subsections below.

Life cycle and reproduction

Annual apparent survival of breeding adults (based on resighting data) over three years in Idaho was 89% ± 0.10 SD, 64% ± 0.10 SD, and 84% ± 0.16 SD, but is probably an underestimate, as apparent survival may not accurately reflect true survival (Dugger and Dugger 2020). Juvenile survival is unknown, but the survival of radio-marked chicks from hatching to fledging in Idaho was 39% (20 of 51 chicks, n = 3 years), but highly variable from year to year (15% to 75%; Redmond and Jenni 1986). Average longevity is estimated at eight to ten years (Redmond and Jenni 1986), but is uncertain due to the lack of specific research. However, the closely related Bristle-thighed Curlew (Numenius tahitiensis) has a record longevity of 23 years and 10 months (Marks 1992). Female Long-billed Curlews reach reproductive maturity at 3 to 4 years and males, at 2 to 3 years (Redmond and Jenni 1986). Bird et al. (2020) estimated generation length in the species to be 6.7 years.

Long-billed Curlew typically nests in open habitats, from native grassland to agricultural lands such as hayfields and cattle pastures (Dugger and Dugger 2020). Preferred nest sites have shorter vegetation, and less bare ground and grass and shrub cover than random sites (Coates et al. 2019), and are often in areas with vegetation of variable height and density (Pampush and Anthony 1993; Hooper and Pitt 1996; Dugger and Dugger 2020). Nests are often built close to cow pies and other mounds or objects (Cochrane and Anderson 1987; Coates et al. 2019). Surrounding habitat varies from thick residual and growing vegetation with relatively little bare ground present (Paton and Dalton 1994) to flat grassy uplands or gravelly ridges and hillsides with thick grass or sagebrush cover (Campbell et al. 1990).

The nest bowl is a shallow depression in the ground, and the male often begins making the scrape as part of courtship (Jenni et al. 1981), although females also contribute once the scrape has been initiated. Nest-lining material is variable and can include small pebbles; bark; grass; droppings of livestock, rabbits (Leporidae) or Canada Goose (Branta canadensis); and small stems, twigs, seeds, and leaves of Cheatgrass (Bromus tectorum; Wolfe 1931; Allen 1980; Jenni et al. 1981; Campbell et al. 1990). Some nests are quite substantial, others sparsely lined, depending on the availability of nesting material (Allen 1980). No reuse of old nests is reported, but the same nesting territory may be used in successive years (Redmond and Jenni 1982).

Only one clutch is laid annually (Allen 1980; Jenni et al. 1981; Paton and Dalton 1994), with few records of re-nesting after nest failure (Allen 1980; Bradley unpubl. data). Clutch size is typically four eggs, but can range from two to five (Sadler and Maher 1976; Redmond and Jenni 1986; Pampush and Anthony 1993; Cannings 1999; Bradley unpubl. data). Records from the British Columbia Nest Records Scheme (n = 31) show an average clutch size of 3.5 eggs (Cannings 1999), although more recent data collected between 2017 and 2021 suggest an average clutch size of 3.6 (n = 19; Bradley unpubl. data). The earliest egg-laying date reported is 11 April in British Columbia and early May in Saskatchewan (Maher 1973; Roy 1996; Bradley unpubl. data). Late nest initiation dates include 4 June in British Columbia (Campbell et al. 1990) and early July in Saskatchewan. Both sexes participate in incubation, the female during the day and the male at night (Allen 1980; Bradley unpubl. data; Carlisle unpubl. data). The incubation period ranges from 27 to 30 days (Graul 1971). The precocial chicks hatch synchronously and begin to leave the nest within three hours of hatching (Allen 1980).

Habitat requirements

Breeding habitat

Shortgrass-prairie or mixed-prairie habitat is strongly preferred (King 1978; Jenni et al. 1981; Pampush 1981; De Smet 1992; Pampush and Anthony 1993; Hooper and Pitt 1996; Dechant et al. 2001). Grasslands with trees, a high density of shrubs (for example, sagebrush, Artemisia spp.) or tall, dense grass are generally avoided (Pampush 1981; Campbell et al. 1990; Pampush and Anthony 1993). Open, sparse grassland habitats may facilitate predator detection or permit more efficient foraging with a long bill than denser vegetation does (Redmond 1986). Areas with taller and denser grass may be used during brood rearing, when shade and camouflage from predators are presumably more important for chicks (Jenni et al. 1981), but may also reflect a decline in the availability of habitats with shorter vegetation as the season progresses. See also Adaptability.

Migration habitat

Although its habitat during migration is poorly studied, Long-billed Curlew uses a wide range of habitat at this time, including dry shortgrass prairie, wetlands associated with alkali lakes, playa lakes, wet coastal pasture, tidal mudflats, salt marsh, alfalfa fields, barley fields, fallow agricultural fields and harvested rice fields (Colwell and Dodd 1995; Davis 1996; Warnock et al. 1998; Manzano-Fischer et al. 1999; Danufsky 2000). In fall, in northern Chihuahua, Mexico, birds are seen in association with prairie dog (Cynomys spp.) colonies (Manzano-Fischer et al. 1999). In the Playa Lakes region of Texas, 95% or more of flocks in summer and fall used sparsely vegetated wetlands (< 33% vegetation cover) out of proportion to their availability (Davis 1996). Within playas, deep water (> 16 cm deep) is generally avoided, and shallow water (0 to 4 cm) is preferred (Davis 1996).

Tracking data reveal that during migration, Long-billed Curlew often favours wetter sites rather than the drier areas surrounding them, including Malheur National Wildlife Refuge, Oregon, and centre-pivot irrigation fields in arid parts of eastern Washington, Oregon and Idaho (Bradley unpubl. data).

Winter habitat

Along the Pacific Coast, winter habitat used by the species includes tidal estuaries, wet pasture and coastlines; however, unlike Willet (Tringa semipalmata) and Marbled Godwit, it rarely occurs along sandy beaches (Stenzel et al. 1976; Colwell and Sundeen 2000). High-elevation salt marshes are commonly used as high-tide roosts (Page et al. 1979; Danufsky 2000).

The most extensive data on habitat use in winter have been collected in the Humboldt Bay area of California. Salt marsh (37%) and tidal mudflat (27%) habitats were the most frequently used among the 10 habitat types surveyed by Gerstenberg (1979). Individuals aggregate in intertidal habitats, which occur more frequently in areas with a high abundance of tidal channels, and at higher elevation sites in the bay (Danufsky 2000). With the onset of winter rains, which occur from October to February, Long-billed Curlews shift to using surrounding pastures (Mathis 2000); during this period, foraging on mudflats may be more difficult, while earthworms (Annelida) are more readily available in pastures because of the raised water table and softened soil.

In Laguna Madre, along the Texas Gulf Coast, Long-billed Curlews almost exclusively use shallowly inundated mudflats with Shoal-grass (Halodule wrightii), some Turtle-grass (Thalassia testudinum), Manatee-grass (Syringodium filiforme), and Engelmann’s Sea-grass (Halophila engelmannii), and covered portions of the lower zone (similar to Marbled Godwits; Brush 1995). Individuals there move between intertidal flats and inland areas, where habitat use has not been studied.

In California’s Central Valley, Long-billed Curlew uses flooded and unflooded cultivated rice (Oryza spp.) fields, especially in dry years, as well as managed wetlands, evaporation ponds, sewage ponds and grassland habitats (Day and Colwell 1998; Elphick and Oring 1998; Shuford et al. 1998; Elphick 2000). Alfalfa (Medicago spp.) fields and pasture had the highest probability of use by curlews both during the dry and wet seasons, while only in the dry season did field and row crops have similar and significant selection coefficients to those of pasture (Sesser 2013). Among shallow-water habitats, flooded agricultural fields were used most in winter and managed wetlands, in spring, while in summer and fall, use was more broadly divided among pastures, drainage ditches, sloughs, streams, farm ponds and reservoirs (Shuford et al. 1998).

Movement, migration, and dispersal

In Saskatchewan and Alberta, Long-billed Curlews return to the breeding grounds in early to mid-April, most arriving during the third week of April (Renaud 1980; Saunders 2001). In British Columbia, they begin to return in mid-March, with spring arrival peaking in late March to early April (Cannings et al. 1987; Campbell et al. 1990; Bradley unpubl. data).

Two to three weeks after the chicks hatch, the female abandons the brood and the male assumes all parental duties until the young become independent at 41 to 45 days after hatching (Allen 1980). In British Columbia, post-breeding flocks of 5 to 10 birds begin to assemble and disperse from nesting areas in July and most have left by mid-August, although a few birds remain until late October (Campbell et al. 1990; Bradley unpubl. data). In Saskatchewan and Alberta, most curlews have left by the end of August (Pinel et al. 1991). In Alberta, there are a number of records of large groups of curlews (from 58 to 400) observed feeding together in late June, July and early August (Dickson and Beyersbergen 1998; Dale et al. 1999; Saunders 2001). Migration staging sites are poorly described in the literature, but recent satellite tracking data revealed important stopover sites including the Malheur National Wildlife Refuge and irrigated fields in eastern Washington and Oregon, and northern Nevada (n = 7 birds; Bradley unpubl. data).

Redmond and Jenni (1986) did not observe any yearlings on the breeding grounds and cited reports of Long-billed Curlew remaining on the winter range throughout the year, suggesting that yearlings and possibly some two-year-olds do not attempt a northward migration. However, Allen (1980) observed small flocks of curlews in Washington in summer that she assumed were sub-adults, and Campbell et al. (1990) reported small flocks at breeding areas in British Columbia in May and June after nesting had begun, and suggested that these are likely non-breeding birds. Ohanjanian (1985) reported flocks of birds in the pre-breeding period on Skookumchuck Prairie in southeastern British Columbia. There are no similar observations from Alberta or Saskatchewan (Saunders 2001).

Males are more likely to breed close to their natal site and show higher site fidelity than females, which may not return if exposed to excessive disturbance or nest loss (Redmond and Jenni 1982). Satellite tracking data in British Columbia reveal that pairs often return to within a few kilometres of the same general area from year to year (Bradley unpubl. data).

Interspecific interactions

Diet

During the breeding season, Long-billed Curlew appears to be an opportunistic forager, feeding primarily on carabid beetles and grasshoppers (Redmond and Jenni 1985; Ohanjanian 1992), as well as earthworms in alfalfa fields (Ohanjanian 1992), the eggs and chicks of other birds, particularly Horned Lark (Eremophila alpestris; Sadler and Maher 1976; Goater and Bush 1986), and occasionally amphibians (Timken 1969).

At tidal estuaries during migration and winter, large, burrow-dwelling mud crabs, ghost shrimp and mud shrimp (Upogebia pugettensis) are preferred, but significant numbers of small (< 3 cm) bivalves, 5 to 45 cm marine worms (polychaetes), and small (< 6 cm) fish are also taken (Stenzel et al. 1976; Boland 1988; Leeman et al. 2001). Earthworms are an important food in wet coastal pastures (Leeman 2000). In the Chihuahuan Desert, Mexico, prey included 34 different items comprising primarily invertebrates (Coleoptera, Orthoptera), as well as reptiles and plants (Olalla-Kerstupp et al. 2020). At a non-breeding site in coastal Mexico, the majority of prey items were crabs (77%) and bivalves (23%; Navedo et al. 2012).

Predators and competitors

No predators of adults are confirmed, but there are reports of an unsuccessful attempt by Prairie Falcon (Falco mexicanus), and one radio-marked adult being taken by a presumed raptor in British Columbia (Bradley unpubl. data). Young birds are known to be taken by raptors shortly after fledging in Idaho (Redmond and Jenni 1986), and most known predation of young birds is attributed to raptors. One chick was eaten by a Long-tailed Weasel (Mustela frenata; Jenni et al. 1981).

Nest predators include Gopher Snake (Pituophis spp.), canids (Coyote, Canis latrans; Red Fox, Vulpes vulpes; feral dog, Canis familiaris), feral cats (Felis catus), Striped Skunk (Mephitis mephitis), Common Raccoon (Procyon lotor), American Badger (Taxidea taxis), Great Horned Owl (Bubo virginianus) and Black-billed Magpie (Pica hudsonia; Pampush and Anthony 1993). Some nests were also abandoned due to disturbance by livestock or destroyed by trampling by the latter (Redmond and Jenni 1986). Redmond and Jenni (1986) noted high predation by American Badger on Long-billed Curlew eggs in an area of high Townsend’s Ground Squirrel (Spermophilus townsendii) density, compared to an 11% rate across the remainder of the study area.

Adults vigorously chase and attack potential nest and chick predators, including Coyote, Swainson’s Hawk (Buteo swainsoni), Ferruginous Hawk (B. regalis), Northern Harrier (Circus hudsonius), corvids such as Black-billed Magpie and Common Raven (Corvus corax), and humans (Allen 1980; Bradley unpubl. data). Groups of adult curlews will mob raptors flying over territory clusters. When threatened by ground predators, adults perform various displays and calls. An injury-feigning display is used to defend the nest from larger mammalian predators (Allen 1980). Defence behaviour increases as incubation progresses; distraction displays and mobbing becoming most frequent and intense once eggs begin hatching (Jenni et al. 1981). Adults continue to defend the pre-fledged young after they hatch (Allen 1980; Jenni et al. 1981).

Other interactions

There is limited documented information about interspecific interactions. Long-billed Curlew and Willet parasitize each other's nests (Bent 1929; Sugden 1933); curlew nests found with eight eggs (Bent 1929) likely represent intraspecific parasitism. In one instance, Willet and Long-billed Curlew both attended a nest with four Willet eggs and one Long-billed Curlew egg (Bent 1929).

In winter, Long-billed Curlews are often seen in loose flocks (10 to 50) or small groups (2 to 3) in association with Reddish Egret (Egretta rufescens), Great Egret (Ardea alba) and White Ibis (Eudocimus albus), but no specific interactions have been noted.

Park staff at Grasslands National Park, Saskatchewan, observed several Long-billed Curlew and Marbled Godwit disputes at different sites, presumably over territorial boundaries (Put pers. comm. 2023).

Physiological, behavioural, and other adaptations

Reproductive effort by female Long-billed Curlews was found to vary with environmental conditions in Idaho (Redmond and Jenni 1986). In dry years when the vegetation was short, the birds foraged almost exclusively within their breeding territory. In wet years, they laid smaller eggs and travelled farther to forage. It is unknown whether chicks hatching from smaller eggs are less likely to survive, although this is known to be the case with the congeneric Whimbrel (Grant 1991) and birds in general (Martin 1987).

Curlew eggs and chicks are sensitive to weather conditions. In a dry year in Idaho, 5% of nestlings died within three hours of hatching and showed signs of incomplete yolk sac retention and adherence of eggshell fragments. This was possibly a result of insufficient humidity caused by drought conditions (Redmond and Jenni 1986). There is some evidence that chicks occasionally succumb to heat stress, especially in dry years when vegetative cover is limited (Redmond and Jenni 1986).

Long-billed Curlew appears to be somewhat flexible in its choice of nesting habitats. In Alberta, the species occurs in some agricultural areas during the breeding season, including areas of intensive agriculture that contain little or no native grasslands (Saunders 2001). In Saskatchewan, the species is generally observed in cropland only when nearby native grassland is absent, and curlews do not appear to use areas under intensive cultivation (Renaud 1980). In British Columbia, Long-billed Curlews have begun to use agricultural habitats in otherwise unsuitable ecoregions (Cannings 1999) and, in the province’s grassland regions, the species is frequently observed in alfalfa fields, grain fields and tame pasture (Ohanjanian 1992; Cannings 1999).

The reaction of Long-billed Curlew subpopulations to extremes of rainfall or drought is largely unknown and likely varies throughout their range. Climate modelling has indicated that limits of breeding distribution were correlated with high summer precipitation (average > 68.1 mm) in the east, high winter precipitation (average > 89.5 mm) in the west, low winter temperatures (average < -12.2 °C) in the north, and high summer temperatures (average > 24.9 °C) in the south (Price 1995). In Saskatchewan, wetter conditions may have facilitated an increase in curlew numbers in the 1990s (De Smet 1992). In Alberta, it has been suggested that nesting subpopulations near Lost River declined as a result of drought in the late 1980s (De Smet 1992). In Washington, Allen (1980) suggested that drought conditions may decrease breeding success by reducing the areas of dense vegetation required for brood rearing. Conversely, in Idaho, drought conditions were found to create more favourable conditions during the courtship and incubation phases (Bicak et al. 1982). Redmond and Jenni (1986) found that chick production was greatest during drought years and that chick mortality was highest in a year of heavy spring rains. In an abnormally wet year, productivity was lowest, likely because of the resulting lush vegetation (Redmond and Jenni 1986; Bradley unpubl. data). Although range fires during the nesting period would presumably be detrimental, Redmond and Jenni (1986) found that an August range fire improved curlew habitat the following year.

Limiting factors

As non-native grasslands can provide suitable breeding habitat for Long-billed Curlew, breeding habitat is likely not limiting in Canada. Some studies in the United States also reported that certain breeding habitats were not saturated (Bicak 1977; Allen 1980; Jenni et al. 1981), suggesting that the availability of suitable breeding habitat is not limiting there.

Low reproductive output is a constraint. With males only starting to breed at 2 to 3 years of age and females at 3 to 4 years (Redmond and Jenni 1986), combined with the species’ relatively small clutch sizes and the rarity of re-nesting, the population is limited to relatively slow growth even under favourable conditions.

Population sizes and trends

Data sources, methods, and uncertainties

The main data source used for the population trend estimates in this report is the North American Breeding Bird Survey (BBS), a standardized roadside survey conducted primarily by volunteers, and coordinated in Canada by the Canadian Wildlife Service (Government of Canada 2021). The program began in 1966 and is the primary source for assessing long-term, large-scale population change for over 400 breeding bird species in Canada and the U.S. (Government of Canada 2021). Surveys are run along permanent 39.2-km routes that comprise 50 stops, spaced 0.8 km apart. Each route is covered once annually from late May to early July, during the height of the breeding season for most songbirds, and beginning one half-hour before sunrise. At each stop, observers document the total number of individuals of each bird species heard from any distance or visually observed within 0.4 km of each stop during a three-minute observation period (Government of Canada 2021). These data are analyzed on a yearly basis to provide information on bird population trends, relative abundance, and species composition and richness at the local, regional and continental scales using a hierarchical generalized additive model (GAM). The BBS is not particularly well suited to monitoring Long-billed Curlew for a number of reasons: firstly, the species occurs along a relatively small number of routes and the species’ detectability is low during the brief point counts (Fellows and Jones 2009). Secondly, the BBS is conducted along roads, which birds may avoid due to disturbance. Lastly, Long-billed Curlews are most detectable between their arrival on the breeding grounds and the pre-incubation period, from approximately mid-April to mid-May, when males are performing their aerial display flights and are most conspicuous (Stanley and Skagen 2007). However, the limitations of the BBS have remained consistent over time, and therefore trends derived from the data are considered relevant, especially as there are no similar data sources available for the species across large temporal and spatial scales. The reliability of BBS trends over the time frames of interest is considered high for this species.

The eBird database, composed of records entered by naturalists around the world of birds they have seen or heard, has grown exponentially in recent years, providing information on Long-billed Curlew throughout its global range. Observations submitted to the eBird database (eBird 2022) are reviewed by expert regional reviewers who control the quality of submissions to ensure data integrity, although these reviews are generally restricted to anomalous observations (for example, those that are out-of-range for a species, or involve an unusually high count). Recent trends analyses have also been generated from these datasets for a number of species, including Long-billed Curlew (Fink et al. 2023). Trends in cumulative changes in estimated relative abundance are calculated both range-wide and for 27 km x 27 km cells sampling the breadth of the Canadian population (Fink et al. 2023).

The size of the population in British Columbia was estimated from the results of a citizen science survey conducted in 2022 (Bradley and Torrenta 2022). The survey was completed by 150 volunteers who surveyed 1,576 point count stations over 95 routes that were pre-selected to attempt to reach a compromise between accessibility and representation of suitable habitat types. A total of 270 individual curlews were detected in 60% of the survey routes, representing a minimum population estimate for the province. In order to obtain a provincial estimate, the minimum number of birds was then extrapolated by multiplying the raw bird densities by the availability of suitable habitat determined using a provincial land-cover GIS layer (Vegetation Resources Inventory 2021) categorizing each 900 m² tile into one of 14 vegetation types. The vegetation types deemed suitable for Long-billed Curlew were HG (herbaceous graminoid, where graminoids made up over 50% of the herb cover) or HE (herb, where there is no distinction between forbs and graminoids). As forb cover is generally less suitable for curlews compared to graminoid cover, the summed total area of land-cover class HG in each of five regions was deemed as optimal habitat for curlews, and the summed area of HG and HE, to represent less optimal habitat. The population density derived from the survey was then multiplied by the summed areas of the HG and HG+HE land-cover classes respectively in each region to provide an upper and lower estimate. This estimate was not ground-truthed, and did not account for areas where birds have declined or disappeared (see Fluctuations and trends, below). Jones et al. (2008) also conducted a survey in British Columbia for the species in 2005; the two surveys mainly differed in their methods and scope, and the reliance on land-cover layers in the more recent (2022) survey.

New population estimates for the Prairie provinces were derived from a pixel-based density model (800 m x 800 m resolution), which was developed using data collected between 2009 and 2018 during roughly 70,000 BBS point counts and modelled using boosted regression trees (for details see Appendix 6 in Prairie Habitat Joint Venture 2021). Spatial covariates used in the model included land cover, the Normalized Difference Vegetation Index, and various weather and topographic variables. This model, which statistically controlled for imperfect detection (Sólymos et al. 2013), predicts the density (individual/ha) of Long-billed Curlews in every pixel throughout Bird Conservation Region 11 – Prairie Potholes. Population size was estimated by multiplying the density estimate in each pixel by the pixel area, then summing these values across all pixels. The population estimates are based on the median values of the results of 100 different bootstrap models, and 90% confidence intervals based on the 5% and 95% quantiles. Values were then multiplied by a pair-correction value of 1.2 to account for differences in detectability between the sexes to derive a final population estimate (Robinson unpubl. data). Targeted landowner surveys were also carried out in southwestern Manitoba in an area where a single bird was detected in June 2021 (Koes 2021), but no additional records have resulted from those surveys (Poole pers. comm. 2024; see Abundance, below).

Element occurrences were gathered from provincial Conservation Data Centres, eBird, the British Columbia Breeding Bird Atlas (2008 to 2012), the Alberta Fisheries and Wildlife Information Management System (FWMIS), and the Saskatchewan Breeding Bird Atlas (2017 to 2021). Observations entered in eBird (eBird 2022) were filtered based on the year (2011 to 2021), and the time of year (restricted to the breeding period, mid-March to the beginning of September). The British Columbia and Saskatchewan breeding bird atlas projects are surveys in which volunteers conduct point counts at predetermined points and search for breeding evidence in 10 km² plots. Although some provinces have conducted a breeding bird atlas more than once, this is not the case for British Columbia and Saskatchewan, and their atlas results are not directly comparable with any past surveys. These data were also curated by regional reviewers to ensure data quality.

Abundance

The global population estimate for Long-billed Curlew is 140,000 mature individuals (Andres et al. 2012), while the previous published estimate for Canada (based on range-wide transect-based surveys during the early breeding season using a stratified random design) was 17,000 to 43,000 mature individuals (Jones et al. 2008). A 2021 survey conducted in the Cariboo-Chilcotin region of British Columbia found 146 birds (Jones 2021), a decrease from the findings of similar surveys in 2002 (232), 2003 (220), and 2004 (211; Van Spall and Steciw 2004). The most recent estimate for the British Columbia subpopulation, following targeted surveys in 2022, is a minimum of 2,693 and a maximum of 10,681 birds (Bradley and Torrenta 2022). The 2022 British Columbia population estimate encompasses the estimate in a previous study in 2005 of 7,436 birds (Jones et al. 2008).

The estimates from extrapolations from density models suggest populations (at a 90% CI) of 87,834 (73,806 to 109,868) in Alberta, 48,832 (39,256 to 59,318) in Saskatchewan, and 417 (236 to 607) in Manitoba (Figure 3) despite the fact that the species is considered extirpated in that province. If credible, the recent models suggest that there may be some landscapes or areas in Manitoba that might support curlews; however, apart from a 2021 record of a single bird calling in the southwestern corner of the province (Koes 2021), there is no evidence of curlews using these areas (Poole pers. comm. 2024). The apparent increases in the population estimates for Alberta, Saskatchewan and Manitoba relative to earlier estimates presumably reflect a change in the analytical approach (with modelled density estimates that are high relative to the previous survey-based estimates, cf. Jones et al. 2008; Dugger and Dugger 2020) rather than an actual increase over past population estimates (see Trends).

Figure 3. Model-based estimates of the density of Long-billed Curlews in Bird Conservation Region 11 – Prairie Potholes (Robinson unpubl. data). Note that the model estimates a very small population occurring in its historical range in Manitoba, albeit at numbers and densities too low to be depicted here (see text).

Fluctuations and trends

Evidence for past (3 generations/10 years) or continuing decline:^{Footnote 1}

The modelled index of Canadian population abundance based on BBS data shows a fairly stable level until around 2005, followed by a steady decline thereafter (Figure 4). The average annual trend in Canada between 2001 and 2021 is -3.50% (95% CI, -5.26 to -1.84; Table 1), which represents a cumulative change of -51.0% over 20 years (95% CI, -66.7 to -31.7), or three generations. This trend, which is considered to have high reliability, represents a 0.97 probability of a decline greater than 30% and a 0.54 probability of a decline greater than 50% (Table 1). In Alberta, a particularly steep decline of 5.44% annually (95% CI, -7.47 to -3.42) was found during this three-generation period, representing a cumulative change of -67.3% (95% CI, -80.8 to -52.9; Table 1). The eastern portion of the Canadian Prairie subpopulation in Saskatchewan has shown a non-significant decline of 1.22% per year (95% CI, -5.26 to 1.49), representing a point estimate of cumulative change of -21.8% (95% CI, -70.9 to 23.1; Table 1) over three generations, but is associated with greater uncertainty. The British Columbia population has shown a non-significant positive trend in the past 20 years of 1.40% (95% CI, -2.08 to 5.37), representing a point estimate of cumulative change of 32.2%, albeit with wide confidence intervals of around zero (95% CI, -42.4 to 165.0). Cannings (1999) and more recently, other observers (Bradley pers. obs. 2022) have noted that the breeding range in British Columbia has expanded along the Fraser River in the Rocky Mountain Trench, around the confluence of the Fraser and Nechako rivers west to Burns Lake, and on the western Chilcotin Plateau. However, there is evidence of local extirpations or local declines in abundance in the North and South Okanagan and Shuswap regions (Davidson and Mahony 2015; Cannings pers. comm. 2023; Charlesworth pers. comm. 2023) and the Cariboo-Chilcotin region (see Abundance, above).

Ten-year breeding season trends (17 May–14 June, 2012 to 2022) have been estimated from range-wide citizen science observations submitted to eBird. For Canada, the percent change for that period is negative, but non-significant (-0.4%; 80% CI, -6.0 to 11.6; Fink et al. 2023). Three-generation trends for these data are not available. Compared to the trend estimates using BBS data, those using eBird data are still new (range-wide trends only available beginning in late 2023) and their limitations are not yet well understood.

Figure 4. Change in average annual index of abundance for Long-billed Curlew in Canada based on Breeding Bird Survey data from 1970 to 2021 (n = 121 routes). The right-hand panel represents the three-generation (20-year) trend. The light-grey line in each panel shows the smoothed trend, while the dark-grey and blue-grey shading show the 50% and 95% credible intervals, respectively (Smith et al. 2023).

Long-term historical trends

The long-term (1970 to 2021) BBS data for Canada indicate an average annual trend of -0.98% (95% CI, -1.97 to 0.06), amounting to a cumulative change of -39.6% (-67.0% to -2.86%; Table 1). This annual rate of decline has increased during the past three generations (2001 to 2021: -3.50%; 95% CI, -5.26 to -1.84), or the past 10 years (2011 to 2021: -4.40%; 95% CI, -7.27 to -1.62). As with the shorter term trends, the greatest long-term declines have been observed in Alberta, with an average annual trend of -1.87% (95% CI, -3.07 to -0.73%), amounting to a cumulative long-term change of -61.7% (95% CI, -83.8 to -36.7). The long-term trend estimates for Saskatchewan and British Columbia are slightly positive, but with 95% CIs broadly overlapping zero (Table 1), the true nature of these trends is uncertain. In Canada, Long-billed Curlew historically bred from south-central British Columbia east through southern Alberta and Saskatchewan to southern Manitoba, where it nested “in moderate numbers” near Pembina and was “frequent” in spring on the Souris plain (Thompson 1891); however, it was last known to breed in Manitoba in the mid-1980s. In fact, the breeding and wintering ranges of the species across North America have undergone a sizeable contraction since the start of the twentieth century (see Global range, above).

Population fluctuations

There is no evidence for large population fluctuations in this species.

Severe fragmentation

The population is not severely fragmented. The species has a high dispersal ability, and the majority of the habitat used by Long-billed Curlew is not separated by large distances.

Rescue effect

Immigration from outside Canada has not been documented, but presumably has occurred, and immigrants would be adapted to survive. On the basis of BBS data, a three-generation increase has occurred from 2001 to 2021 in Montana (3.14% per year; 95% CI, 1.62 to 4.97), the state that is closest to the majority of the Canadian Prairie subpopulation (Smith et al. 2023). The British Columbia subpopulation would likely be dependent on rescue from Idaho or Washington, where the probability of a three-generation decline is 88% and 90%, respectively (Smith et al. 2023). The eBird breeding season trends for the U.S. (2011 to 2021; see Fluctuations and trends, above) show a strong annual rate of decline (-9.5%; 80% CI, -5.7 to -16.9; Fink et al. 2023), and recent (2011 to 2021) BBS trends suggest a contraction toward the core of the species’ range, with moderate to strong declines along the western, northern and eastern edges (Figure 5). Owing to the steepness of the short-term declines (2011 to 2021: -7.04% per year; 95% CI, -10.80 to -3.70) and three-generation declines (-5.44%; -7.47 to -3.42; Table 1) recorded in Alberta, it is unlikely that immigrants would thrive there. Overall, while some immigration is possible, the probability of rescue resulting in a change of status is unlikely.

Figure 5. Short-term (2011 to 2021) annual rates of population change for Long-billed Curlew, estimated from Breeding Bird Survey data for Bird Conservation Regions in provinces and states with sufficient data to estimate trends (Smith et al. 2023).

Threats

Historical, long-term, and continuing habitat trends

Habitat loss has historically affected the areas occupied by Long-billed Curlew. Loss and fragmentation of habitat due to expansion of oil and gas drilling has put increasing pressure on the species over the past several decades in the Prairies (COSEWIC 2011), by fragmenting and replacing native prairie with well sites and pipelines (Prescott and Bilyk 1996; Saunders 2001; Canadian Prairie Partners in Flight 2004). In Alberta and Saskatchewan, about 57% and 79% of native prairie grasslands have been lost in the past century, respectively, mainly due to agriculture (Nernberg and Ingstrup 2005). Most of the prime land was converted for cultivation and grazing long ago, starting prior to 1900. However, the loss of grasslands has continued, with 6 to 8% and 8 to 11% of the remaining native grasslands in Saskatchewan and Alberta, respectively, converted during the 1985 to 2001 period (Watmough and Schmoll 2007), and a further 3.6% in Saskatchewan and 4.5% in Alberta between 2001 and 2011 (Watmough et al. 2017).

In British Columbia, much of the grassland habitat in the Okanagan and Thompson River valleys has been converted to agricultural uses such as orchards, vineyards or ginseng (Panax sp.) plantations (Cannings 1999; Lea 2008). However, habitat losses in these areas may have been partially counterbalanced by gains in the Rocky Mountain Trench resulting from the clearing of forested lands for field crops, such as alfalfa, a crop thought to be compatible with Long-billed Curlew’s habitat requirements (Cannings 1999). Approximately 3% to 11% of native grasslands have been lost to cultivated fields in the southern interior of British Columbia (Grasslands Conservation Council of British Columbia 2004). The current breeding range expansion northward and farther inland in British Columbia may lead to more interaction with large areas designated as Agricultural Land Reserve, with potential beneficial effects in the future.

Considerable losses of suitable habitat have also occurred on the wintering grounds. Drainage or increased sedimentation of wetlands and conversion of upland habitat to row crops, vineyards and orchards have all decreased the availability of wintering areas (Kennish 2001; Taft and Haig 2003; see also Agriculture and Aquaculture under Current and Projected Future Threats, below).

The invasion of exotic plant species such as Leafy Spurge (Euphorbia esula) and knapweeds (Centaurea spp.) may have further reduced the amount and quality of suitable habitat for Long-billed Curlews by displacing the native graminoid vegetation (COSEWIC 2002). As early as the 1950s, Leafy Spurge had invaded approximately 5,000 ha of grasslands in Saskatchewan and an additional 5,000 ha of cultivated land (Selleck et al. 1962). In Alberta, Leafy Spurge has infested approximately 6,000 ha of land, mainly in the southeastern part of the province (McLay and Cole 1995). The distribution of this invasive species in Alberta and Saskatchewan broadly overlaps that of Long-billed Curlew in the two provinces. Knapweeds have been implicated in the overall loss in the integrity of grassland ecosystems in the southern interior of British Columbia, reducing the abundance and productivity of native grasses (Gayton 2004). British Columbia grasslands infested with knapweeds and older plantings of Crested Wheatgrass (Agropyron cristatum) are not suitable for Long-billed Curlew because of the tallness of these plants (Ohanjanian 1992).

Current and projected future threats

Long-billed Curlew is vulnerable to the cumulative effects of various threats throughout its annual cycle. These are categorized below and in Appendix 1, following the IUCN–CMP (International Union for Conservation of Nature–Conservation Measures Partnership) unified threats classification system (see Salafsky et al. 2008 for definitions and Master et al. 2012 for guidelines). The evaluation assesses impacts for each of 11 main categories of threats and their subcategories, based on the scope (proportion of population exposed to the threat over the next 10-year period), severity (predicted population decline among those exposed to the threat, during the next 10 years or 3 generations, whichever is longer), and timing of each threat. The overall threat impact is calculated by taking into account the separate impacts of all threat categories and can be adjusted by the species experts participating in the threats evaluation.

For Long-billed Curlew, the overall threat impact is estimated to be High–Medium, corresponding to an anticipated further decline of between 3% and 70% over the next 20 years (equivalent to three generations; see Appendix 1 for details). First-level threats with impacts assessed as Low or higher are discussed below in numerical order, followed by first-level threats whose impact is Unknown. Only threats with an impact assessed as Low or higher or as Unknown are included; for a more exhaustive list of threats, see Appendix 1.

IUCN 1, Residential and commercial development (low threat impact)

IUCN 1.1, Housing and urban areas (low threat impact) and IUCN 1.2, Commercial and industrial areas (low threat impact)

Native grasslands in Canada continue to be lost due to urban encroachment, mostly in British Columbia. In the valleys of southern British Columbia, the greatest losses of grassland have been attributed to urbanization and the associated extensive transportation corridors needed to support urban areas, especially in the vicinities of Kelowna, Cranbrook and Kamloops (Lea 2008). In the Prairies, urbanization is generally not a threat to Long-billed Curlew.

Anthropogenic development on the species’ wintering grounds outside Canada also poses a threat to the species. For example, in California, over 90% of original wetlands were lost between the 1780s and 1980s (Dahl 1990), with losses of wetland habitat continuing in the present (Warnock pers. comm. 2023). From 1984 to 2018 in the same state, 1.6 million acres (approximately 650,000 ha) of agricultural land was converted to non-agricultural use (California Department of Conservation 2024), and by 2050, 90% of agricultural lands and 58% of pasture lands are projected to experience pressure from housing growth (Mann et al. 2014). The potential risk of development at communal roost sites poses a threat in non-breeding areas where big flocks are commonly observed near feeding habitat (Carlisle pers. comm. 2023).

IUCN 1.3, Tourism and recreation areas (low threat impact)

Resort and coastal development is ongoing, in particular along the coasts of eastern Florida and the Gulf of Mexico (Elliot and McKnight 2000; Hunter et al. 2002).

IUCN 2, Agriculture and aquaculture (low threat impact)

IUCN 2.1, Annual and perennial non-timber crops (low threat impact)

The conversion of grassland to annual or perennial crops represents an ongoing threat to Long-billed Curlew, and the resulting habitat may be less optimal than native grasslands. The most recent estimates put losses of Canada’s grasslands (native and tame combined) between 2011 and 2017 at 1.32% (Robinson unpubl. data), representing a total loss of roughly 200,000 ha over that period (Agriculture and Agri-Food Canada 2019). The recent losses represent mostly conversion of small patches of grassland to cropland within large mosaics of cultivated land (Watmough and Schmoll 2007). Reasons for land clearing have also changed in recent years, with an ongoing intensification of agriculture in some areas—for example, in the Okanagan region of B.C.—from fields usable for Long-billed Curlew to grape monoculture. Conversion of native grasslands to agricultural use may result in not only direct habitat loss, but also habitat fragmentation (that is, changes in the spatial configuration of remaining habitat patches; see IUCN 7.3, Other Ecosystem Modifications). Considerable modifications in agricultural practices in the U.S. and Mexico are also converting wintering habitat—for example, grasslands, or land with agricultural practices that are compatible with Long-billed Curlew use—to habitat not usable by curlews; this conversion may currently be the greatest threat facing the species. In California, for example, land is being converted to almond orchards, which are not used by curlews (Warnock pers. comm. 2023). The area under almond crops in California grew from about 169,000 ha in 1995 to a projected 538,000 ha in 2021, although the rate of growth in this industry is slowing, in part due to potential reductions in groundwater access (Bruno et al. 2021); changing farming practices due to water shortages are also affecting curlew habitat in agricultural areas (see IUCN 7.2, Dams and Water Management/Use).

The evidence for direct mortality in this species from agricultural use (mechanized farming) is anecdotal. Presumably, activities such as plowing, haying and manure spreading can result in direct losses of nests, eggs and chicks, as reported in the U.S. (Forsythe 1972; Shackford 1994).

In southern Alberta, Long-billed Curlew has been recorded successfully nesting and rearing young in agricultural areas, instead of grasslands (DeVries et al. 2010); this appears to be much less prevalent in British Columbia (Davidson and Mahony 2015). Such flexibility may reduce the future severity of this threat. Some factors such as the flooding of nests during the irrigation of hayfields may potentially affect nest success (Hartman and Oring 2009). To date, no study clearly demonstrates that adult survival or reproductive success is significantly impaired on agricultural lands compared to native grasslands, so this may show the species’ relative tolerance of crop fields and hayfields as habitat (although pesticide use on some agricultural lands poses a separate threat – see IUCN 7.3,Other Ecosystem Modifications and IUCN 9.3,Agricultural and Forestry Effluents).

IUCN 3, Energy production and mining (low threat impact)

IUCN 3.1, Oil and gas drilling (low threat impact)

Habitat loss and fragmentation due to expansion of oil and gas drilling continues to threaten Long-billed Curlew in the Prairies. Energy development has also been shown to facilitate the introduction and expansion of invasive plant species (see IUCN 7.3, Other Ecosystem Modifications; Bayne and Dale 2010).

Helium extraction is becoming a bigger threat and is expanding in Long-billed Curlew’s breeding range, especially in Saskatchewan (Government of Saskatchewan 2021), where the province aims to provide 10% of the world's helium by 2030.

Habitat loss due to energy development is also present at migration stopover sites in the U.S., where some well re-openings have occurred or are ongoing (Warnock pers. comm. 2023).

In British Columbia, the majority of oil and gas drilling activity takes place in the northeastern part of the province, with the resulting heavily fragmented areas causing changes in wildlife movements and the spread of detrimental invasive plants, in addition to habitat loss. While the species’ range does not currently extend to this region, the trend towards the expansion of the species’ breeding range northward and farther inland in British Columbia will increasingly bring the species in contact with areas of oil and gas development. This may lead to detrimental impacts that need to be considered in the future.

IUCN 3.3, Renewable energy (low threat impact)

Wind energy development and encroachment in grasslands used by curlews poses a potential and increasing threat in the Canadian Prairies (through the loss and fragmentation of breeding habitat, and direct collisions with wind towers) and on the species’ migration routes in the Great Plains (Carlisle pers. comm. 2023; Warnock pers. comm. 2023). Conversion of grasslands to solar farms is also increasing (Ott et al. 2021; Bernath-Plaisted et al. 2023). A study of Eurasian Curlew (Numenius arquata) showed that migrating curlews are prone to wind turbine collisions (Schwemmer et al. 2022). However, there is no mention of Long-billed Curlew in the Wind Energy Bird and Bat Monitoring Database (Bird Studies Canada et al. 2018).

IUCN 5, Biological resource use (low threat impact)

IUCN 5.1, Hunting and collecting terrestrial animals (low threat impact)

In Canada, this threat is largely historical. Although hunting led to the original decimation of the Long-billed Curlew population (De Smet 1992), there is no recent evidence of incidental/illegal shooting of curlews in Canada. However, considering their conspicuous vocalizations, large size and tendency to mob intruders, curlews present a tempting target, and some may fall victim to recreational shooters, especially in areas where shooting ground squirrels or prairie dogs is common practice.

Some risk of mortality may also occur during migration and in winter from hunting and poaching (illegal target shooting). Illegal shooting of curlews is still a problem on federal (Bureau of Land Management) land in portions of the U.S. range, with variable intensity and effects across the landscape, ranging from large numbers of birds shot in some areas to none in others (Carlisle pers. comm. 2023). For example, in Idaho, Redmond and Jenni (1986) documented three nesting adults that had been shot and six others that were believed to have been shot; Katzner et al. (2020) reported that 7 of 21 (33%) of radio-tracked curlews were illegally shot in this state.

IUCN 7, Natural system modifications (low threat impact)

IUCN 7.1, Fire and fire suppression (low threat impact)

Until European settlement of western Canada, fire was an important tool used by First Nations peoples to manage and maintain grasslands, with mixed-grass prairie burned at three- to five-year intervals. As agricultural conversion proceeded, the use of fire as a management tool decreased and natural fires were suppressed either directly or indirectly, by means of firebreaks, roads or other habitat alterations; in contrast, today, less than 1% of the mixed-grass prairie burns in any given year (Samson et al. 2004). Fire control and suppression can result in the encroachment of shrub growth on prairie grasslands and, in British Columbia, the encroachment of coniferous forests on grassland and savannah habitats, specifically in the South Okanagan and Similkameen valleys and the Chilcotin grasslands (Strang and Parminter 1980; Turner and Krannitz 2001). This not only leads to the direct loss of habitat, but also reduces the quality of the adjacent habitat, as Long-billed Curlew rarely breeds near treed or shrubby areas (Cannings 1999). In addition, fire suppression probably increases vulnerability to predation, as curlews’ survival depends on their ability to detect predators (see IUCN 8.2, Problematic Native Species/Diseases).

Most extant grasslands are grazed by cattle in western Canada, which could mitigate some of the effects of fire suppression. Prescribed fire can be similar to grazing in terms of creating habitat, and the interaction between fire and grazing (pyric herbivory) may be an important alternative management strategy to support and restore populations of some grassland bird species (for example, Dickcissel [Spiza americana], Grasshopper Sparrow [Ammodramus savannarum]; Davis et al. 2016).

Although the areas most affected by forest fires are not occupied by curlews, wildfires are becoming an increasing threat. In British Columbia, the timing of fires used to be outside the nest occupancy phase (Dugger and Dugger 2020), but western Canada is now seeing hotter and drier summers, with fire seasons starting earlier and lasting longer than they did historically. In particular, northern and central British Columbia were heavily affected by wildfires during the 2023 spring/summer season, with a record-breaking 2.2 million ha burned in the province as of early September. Given the evidence that the breeding range is shifting northward in the province, this may lead to increased impacts on local populations.

IUCN 7.2, Dams and water management/use (low threat impact)

Changes to water management (for example, reduction in flood irrigation and other water allocation changes on agricultural lands) are affecting all the species’ wintering grounds in the U.S. and Mexico. The rice fields in California’s Central Valley are used by curlews, but not enough water is currently allocated to sustain the rice fields. In the Salton Sea area, alfalfa has historically been flood-irrigated, but farmers are moving away from that practice, which makes the habitat less suitable for curlews. Given the higher concentration of birds on the wintering grounds and on migration routes, curlews are likely more vulnerable there to local detrimental effects, which include the loss of available roosting/foraging habitat and feeding opportunities (Warnock pers. comm. 2023; Carlisle pers. comm. 2023). Engineering and coast stabilization projects may also be a cause of habitat loss.

IUCN 7.3, Other ecosystem modifications (low threat impact)

Pesticide spraying can reduce the availability, biomass and diversity of prey species, especially grasshoppers. This threat likely occurs widely and, although the severity of its effects is somewhat uncertain, it is thought to be an important threat to Long-billed Curlew (Court pers. comm. 2023; Warnock pers. comm. 2023).

Knapweeds and Leafy Spurge are highly invasive non-native herbs that currently occupy over 100,000 ha of land in British Columbia, primarily in the grasslands in the Southern Interior where Long-billed Curlews occur (British Columbia Ministry of Forests, Lands and Natural Resource Operations and Rural Development 2022). However, the severity of the threat posed to Long-billed Curlew remains unclear.

Invasive plant species are also a threat to Long-billed Curlew on the wintering grounds. For example, Smooth Cordgrass (Sporobolus alterniflorus) has been introduced in the tidal areas of San Francisco Bay in California, where it outcompetes the native vegetation and reduces the suitability of tidal flats for shorebird foraging areas (Frenkel 1987; Daehler and Strong 1996). However, this invasion is currently fairly well controlled through environmental stewardship (California Invasive Plant Council 2023).

IUCN 8, Invasive and other problematic species, genes and diseases (low threat impact)

IUCN 8.1, Invasive non-native/alien species/diseases (unknown threat impact)

Invasive Cheatgrass may directly cause a decrease in reproductive success (for example, nests constructed in Cheatgrass are likely more visible to predators than those in native bunchgrasses; Stocking et al. 2010) and overall bird fitness (Warnock pers. comm. 2023).

IUCN 8.2, Problematic native species/diseases (low threat impact)

Coyote, Red Fox, Black-billed Magpie, Common Raven, Ferruginous Hawk, Swainson’s Hawk and Great Horned Owl are the primary predators of Long-billed Curlew adults and young (Allen 1980; COSEWIC 2002). Predators attacked 10 to 35% of nests in two study areas in the northern United States and accounted for 23% of known chick mortality at one of those sites (Redmond and Jenni 1986; Pampush and Anthony 1993). Populations of some of these predators, such as Coyote, Red Fox, raptors and corvids, have increased in the Canadian Prairies due to anthropogenic habitat changes (COSEWIC 2002), which may cause heightened predation pressure on Long-billed Curlew. Indeed, most mammalian and avian predators benefit from human-built features that fragment habitat, such as roads, trails, fence lines, hedgerows and shelterbelts (Bergin et al. 1997). In particular, the corridors created by fragmentation may increase predation (Kuehl and Clark 2002) by Coyote and Red Fox. In addition, the increased presence of trees, power poles, and fence posts provides more perches or observation sites for raptors such as Ferruginous Hawk, Swainson’s Hawk and Great Horned Owl, which may increase the probability of predation (Bechard et al. 2020; Ng et al. 2020). This may be especially important in British Columbia, where nesting territories are in relatively small grassland patches, surrounded by trees. Ohanjanian (1986) suggested the possibility of increased predation at curlew nesting sites on Skookumchuck Prairie in southeastern British Columbia because of the proximity of trees.

IUCN 8.5, Viral/prion-induced diseases (unknown threat impact)

Avian influenza H5N1 is considered a pervasive threat to wild bird populations of unknown severity. Whether Long-billed Curlew has been affected by this disease is unknown, although mortality has been documented in Eurasian Curlew.

IUCN 9, Pollution (low threat impact)

IUCN 9.2, Industrial and military effluents (unknown threat impact)

In the U.S. and Mexico, some birds are congregating in areas with mining/tailing ponds (for example, gold mines and oil field wastewater facilities). Contaminants in the ponds may be detrimental to curlews’ health, as deaths have been documented in other shorebirds (Ramirez 2010; Warnock pers. comm. 2023).

IUCN 9.3, Agricultural and forestry effluents (low threat impact)

Given that curlews use agricultural fields and aquatic systems throughout their annual cycle, they may be significantly exposed and susceptible to pesticides such as neonicotinoids (Frank et al. 2020; Pietrzak et al. 2020; Anderson et al. 2023).

In British Columbia, increased insecticide use on agricultural lands, particularly in fruit crop areas, can reduce the availability of prey species (see IUCN 7.3, Other Ecosystem Modifications) and, in rare instances, may also be linked to direct mortality in the species (Blus et al. 1985; Fellows and Jones 2009; Dugger and Dugger 2020). The pesticides commonly used for grasshopper control in the Prairies do not have significant direct impacts on birds (Johnson pers. comm. 2001), but may harm Long-billed Curlew indirectly by reducing the availability of prey, particularly grasshoppers (see IUCN 7.3, Other Ecoystem Modifications), with the indirect effects of insect loss likely posing a much greater threat).

During migration and on the wintering grounds, pesticide use on agricultural lands could also cause mortality, especially in areas where it is less regulated. For example, on their wintering grounds in Mexico, curlews are regularly exposed to pesticides (Olalla-Kerstupp et al. 2020).

More generally, a significant relation has been found between the increased use of neonicotinoids and declines in grassland and insectivorous bird populations and diversity in the U.S. (Li et al. 2020). Chronic exposure to neonicotinoids may affect productivity, although no data are available on shorebirds. The cumulative effects of neonicotinoids are not well known.

IUCN 9.6, Excess energy (unknown threat impact)

While it is plausible that noise pollution from industrial activities such as oil and gas drilling and helium extraction could displace or disturb nesting curlews, there are currently no data on the impacts of excess sound on the species.

IUCN 11, Climate change and severe weather (low threat impact)

IUCN 11.1, Habitat shifting and alteration (unknown threat impact)

In winter, Long-billed Curlew may be affected if rising sea levels due to climate change reduce the extent of their foraging areas on tidal flats (Colwell and Mathis 2001). In addition, shifts in the species’ breeding and wintering distribution are likely. The Audubon Society's predictive climate model projects a 92% loss of the current North American summer range by 2080, compared to the year 2000 (National Audubon Society 2019). However, the species’ breeding range in British Columbia has the potential to increase, and a northward shift has already been observed in recent decades (Bradley and Torrenta 2022; but see IUCN 7.1, Fire and Fire Suppression; IUCN 11.2, Droughts; and IUCN 11.3, Temperature Extremes for impacts on areas inland and to the north). On the wintering grounds, habitat expansion and gains are possible, but disruptions are expected as areas with suitable climate and condition move inland and northward (National Audubon Society 2019) or decrease in extent (Mitsch and Hernandez 2013).

IUCN 11.2, Droughts (low threat impact) and IUCN 11.3, Temperature extremes (low threat impact)

As is the case for wildfires, the threat posed by temperature extremes and droughts to Long-billed Curlew is increasing, given the greater frequency and severity of these events due to climate change. The threat to curlews is particularly great if these events occur during nesting season.

Drought reduces the availability of the vegetation needed for brood rearing and may have indirect consequences by altering the abundance, availability and quality of prey (Allen 1980; DeSmet 1992). In addition, droughts and temperature extremes may affect hatching or post-hatching survival, with documented effects on physiology: eggs and chicks are sensitive to heat stress and lack of humidity (for example, incomplete yolk sac retention, adherence of eggshell fragments, direct chick mortality and fledglings in poor body condition; Redmond and Jenni 1986; van de Ven et al. 2020). Avian eggs during incubation are very sensitive to heat stress in general, more so than to cold (Webb 1987).

IUCN 11.4, Storms and flooding (low threat impact)

Increased intensity and frequency of rainfall/snowfall and summer storms may also contribute to nesting failure (Coates 2018). For example, snowstorms occurring early in the breeding season may increase the risk of nest flooding through snow melt. Heavy storms can also cause nest failure or abandonment (Coates et al. 2021).

IUCN 4, Transportation and service corridors (unknown threat impact)

IUCN 4.2, Uutility and service lines

New developments, including the expansion of renewables, result in new power lines. Dead curlews have been found under power lines, which also provide perches for predators; near misses with electrical transmission lines have also been observed (Warnock pers. comm. 2023).

Habitat trends

The amount of remaining native and tame prairie habitat in Canada is estimated at 15.1 million ha, including 7.1 million ha in Alberta and 6.8 million ha in Saskatchewan (Agriculture and Agri-Food Canada 2019). Between 2011 and 2017, losses of native and tame grasslands in Canada were estimated at 1.32% (Robinson unpubl. data), amounting to a total loss of 200,000 ha over that period. However, the rate of loss has abated somewhat compared to 2001 to 2011 (4.5% in Alberta, 3.6% in Saskatchewan; Watmough et al. 2017). Recent (2011 to 2021) population trends suggest a contraction in the species’ range, with moderate to strong declines along the western, northern and eastern edges (see Rescue effect).

Changes in agricultural uses may have altered the quality of the habitat used by Long-billed Curlew. Although the species frequents agricultural habitats, little information is available on habitat selection in agricultural areas or what impact recent changes in agricultural practices—which may include a shift in livestock production, sacrifice of pasture land to grain and biomass production, and increased pesticide use—may have on these birds and their breeding success.

Number of threat locations

Drought (and associated water management changes on the wintering grounds), agricultural conversion, reduced prey availability, growing abundance of invasive plant species, and increasing proximity and abundance of predators are likely to be the greatest threats to the species. As these all act by affecting the availability and/or quality of breeding habitat at regional to very local scales, it is difficult to estimate the number of threat-based locations, which are likely to number at least in the hundreds.

Protection, status, and recovery activities

Legal protection and status

Long-billed Curlew was initially listed on Schedule 3 of the Species at Risk Act as Special Concern. The species was added to Schedule 1 as Special Concern in 2005, with the status reconfirmed by COSEWIC in May 2011. In May 2024, COSEWIC reassessed this species as Threatened. The species and its nests containing a live bird or viable egg are protected under the Migratory Birds Convention Act, 1994 in Canada, and under equivalent legislation in the U.S.

In the U.S., Long-billed Curlew has no status under the Endangered Species Act, but has been designated by the U.S. Fish and Wildlife Service as a Bird of Conservation Concern nationally, in five U.S. Fish and Wildlife Service regions, and in several Bird Conservation Regions. It is also listed as a species of concern in several U.S. states.

Non-legal status and ranks

NatureServe considers Long-billed Curlew Apparently Secure (G4) globally, Vulnerable (N3B) in Canada, and Apparently Secure (N4) in the U.S. (NatureServe 2024). Provincially, Long-billed Curlew is classified as Apparently Secure (S4) in British Columbia, Vulnerable (S3) in Alberta and Saskatchewan, and Presumed Extirpated (SX) in Manitoba (Table 2). In British Columbia, the species is now yellow-listed, and in Alberta it is a species of Special Concern.

^a At start of rank: G = Global; N = National; S = Subnational; B = Breeding. At end of rank: N = Non-breeding, M = Migrant. Numeric rank: 1 = Critically Imperilled; 2 = Imperilled; 3 = Vulnerable; 4 = Apparently Secure; 5 = Secure; NA = Not Applicable; NR = Not Ranked; ? = Inexact numeric rank.

^b Listed as Endangered/Threatened/Special Concern (or equivalent designations) by the jurisdiction in question.

Land tenure and ownership

Less than 1% of Long-billed Curlew breeding habitat in Canada is formally protected (Cannings 1999; Bradley unpubl. data), and no Important Bird and Biodiversity Areas (IBAs) have been specifically designated due to the presence of the species. However, Long-billed Curlew occurs regularly in lower numbers in several IBAs (Birdlife International 2022), and several protected areas in British Columbia, Alberta and Saskatchewan are recognized as being important for the species (Table 3).

In British Columbia, Long-billed Curlew is an Identified Wildlife Management Species, and thus benefits from provisions for establishing Wildlife Habitat Areas (WHAs) coinciding with its known breeding areas, including the implementation of related management measures (Ohanjanian 2004). To date, 11 WHAs for the species have been established in the Rocky Mountain Forest District; however, they are not protected areas and primarily involve restrictions on range practices. Because Long-billed Curlew populations across much of the province may be increasing (Davidson et al. 2015), further WHA establishment is currently unlikely, except perhaps in the North Okanagan and Shuswap areas, where numbers appear to be declining based on local surveys (Davidson and Mahony 2015), and in the Cariboo-Chilcotin region (see above). Protection of large areas of land in the South Okanagan-Similkameen region would protect several known occurrences and benefit the conservation of the species (BC Conservation Data Centre 2022).

Recovery activities

A Management Plan for Long-billed Curlew in Canada was developed in 2013 (Environment Canada 2013), and an Alberta Conservation Management Plan was created in 2010 (Alberta Environment and Parks 2017). Operation Grassland Community, the Prairie Conservation Action Plan and the North American Waterfowl Management Plan (NAWMP) are examples of initiatives in Alberta that have identified the need to protect native grassland and its species. Furthermore, federal and provincial agricultural agencies are implementing soil conservation programs that aim to convert cultivated areas back to grasslands.

Public outreach and stewardship programs targeting Long-billed Curlew have also been implemented (for example, the MultiSAR program in Alberta and in the Prince George area of British Columbia, and a similar action plan for multiple species at risk in southwestern Saskatchewan; Environment and Climate Change Canada 2017). Both of the above programs target landowners with curlew breeding areas on their lands and inform them of range management practices and grazing regimes that conserve or enhance nesting habitat, and protect the species during critical periods (see also Alberta Environment and Parks 2017). Beneficial cattle grazing programs in Grasslands National Park are aimed at optimizing, creating and maintaining habitat for multiple species of grassland birds at risk, including Long-billed Curlew. Long-billed Curlew is also currently (as of the 2023 to 2024 funding cycle) a priority species for recovery projects in Alberta funded under the federal Habitat Stewardship Program (Government of Canada 2023).

Information sources

References cited

Agriculture and Agri-Food Canada. 2019. Annual Crop Inventory, 2019. Website: https://open.Canada.ca/data/en/dataset/ba2645d5-4458-414d-b196-6303ac06c1c9 [accessed January 2022].

Alberta Environment and Parks. 2017. Long-billed Curlew conservation management plan. Species at Risk Conservation Management Plan No. 3. Alberta Environment and Parks, Edmonton, Alberta. 7 pp.

Allen, J.N. 1980. The ecology and behavior of the Long-billed Curlew in southeastern Washington. Wildlife Monographs 73:3-67.

American Ornithologists’ Union (AOU). 1983. Checklist of North American Birds. 6th edition.

Anderson, M.J., A. Valdiviezo, M.H. Conway, C. Farrell, R.K. Andringa, A. Janik, W.A. Chiu, I. Rusyn, and S.A. Hamer. 2023. Imidacloprid exposure is detectable in over one third of wild bird samples from diverse Texas ecoregions. Science of the Total Environment 876:162723. https://doi.org/10.1016/j.scitotenv.2023.162723

Andres, B.A., P.A. Smith, R.I.G. Morrison, C.L. Gratto-Trevor, S.C. Brown, and C.A. Friis. 2012. Population estimates of North American shorebirds. Wader Study Group Bulletin 119:178-194.

Bayne, E.M., and B.C. Dale. 2010. Effects of energy development on songbirds. Pp. 95-114 in D.E. Naugle (ed.). Energy Development and Wildlife Conservation in Western North America, Island Press, Washington, D.C. 308 pp.

BC Conservation Data Centre. 2022. Conservation Status Report: Numenius americanus. B.C. Ministry of Environment. Website: https://a100.gov.bc.ca/pub/eswp/ [accessed Apr 11, 2023].

Bechard, M.J., C.S. Houston, J.H. Sarasola, and A.S. England. 2020. Swainson's Hawk (Buteo swainsoni), version 1.0. In A.F. Poole (ed.). Birds of the World, Cornell Lab of Ornithology, Ithaca, New York. Website: https://doi.org/10.2173/bow.swahaw.01 [accessed February 2022].

Bent, A.C. 1929. Life histories of North American shorebirds, Order Limicolae (Part 2). Bulletin of the United States National Museum 1-412, 66 pls. https://doi.org/10.5479/si.03629236.146.i

Bergin, T.M., L.B. Best, and K.E. Freemark. 1997. An experimental study of predation on artificial nests in roadsides adjacent to agricultural habitats in Iowa. Wilson Bulletin 109:437-448.

Bernath-Plaisted, J.S., M.D. Correll, S.G. Somershoe, A.M. Dwyer, A. Bankert, A. Beh, H. Berlanga, W.A. Boyle, J. Lizardo Cruz-Romo, T.L. George, J. Herkert, N. Koper, A. Macías-Duarte, A.O. Panjabi, O.M. Ramírez-Flores, B. Robinson, I. Ruvalcaba-Ortega, J. Sibbing, E.H. Strasser, M. Titulaer, W.E. Van Pelt, and T. VerCauteren. 2023. Review of Conservation Challenges and Possible Solutions for Grassland Birds of the North American Great Plains. Rangeland Ecology and Management 90:165-185.

Bicak, T.K. 1977. Some eco-ethological aspects of a breeding population of Long-billed Curlew (Numenius americanus) in Nebraska. Master’s thesis, University of Nebraska, Omaha, Nebraska. 94 pp.

Bicak, T.K., R.L. Redmond, and D.A. Jenni. 1982. Effects of grazing on Long-billed Curlew (Numenius americanus) breeding behaviour and ecology in southwest Idaho. Pp. 74-85 in J.M. Peek and P.D. Dalke (eds.). Wildlife-livestock relationships symposium: proceedings. University of Idaho, Forest, Wildlife and Range Experimental Station, Moscow, Idaho.

Bird, J.P., R. Martin, H.R. Akçakaya, J. Gilroy, I.J. Burfield, S.T. Garnett, A. Symes, J. Taylor, Ç.H. Sekercioglu, and S.H. Butchart. 2020. Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology 34:1252-1261.

BirdLife International. 2022. Species factsheet: Numenius americanus. Website: http://www.birdlife.org [accessed January 2022].

Bird Studies Canada, Canadian Wind Energy Association, Environment and Climate Change Canada, and Ontario Ministry of Natural Resources and Forestry. 2018. Wind energy bird and bat monitoring database: summary of the findings from post-construction monitoring reports. Port Rowan, Ontario. 56 pp.

Bishop, L.B. 1910. Two new subspecies of North American birds. Auk 27:59-61.

Blus, L.J., C.J. Henny, and A.J. Krynitsky. 1985. Organochlorine-induced mortality and residues in Long-billed Curlews from Oregon. The Condor 87:563-565.

Boland, J.M. 1988. Ecology of North American shorebirds: latitudinal distributions, community structure, foraging behaviors, and interspecific competition. Ph.D. dissertation, University of California, Los Angeles, California. 512 pp.

Bradley, D.W., and R. Torrenta. 2022. British Columbia Long-billed Curlew survey 2022. Birds Canada, Port Rowan, Ontario. 12 pp.

British Columbia Ministry of Forests, Lands and Natural Resource Operations and Rural Development. 2022. Invasive Alien Plant Program. Website:https://maps.gov.bc.ca/ess/hm/iapp/ [accessed January 2022].

Bruno, E.M., B. Goodrich, and R.J. Sexton. 2021. The outlook for California’s almond market. ARE Update 24(6):9-11.

Brush, T. 1995. Habitat use by wintering shorebirds along the lower Laguna Madre of south Texas. Texas Journal of Science 47:179-190.

California Department of Conservation. 2024. 2016-2018 Farmland Conversion Report. Division of Land Resource Protection, Sacramento, California. 27 pp. Website: https://www.conservation.ca.gov/dlrp/fmmp/Pages/2016-2018_Farmland_Conversion_Report.aspx [accessed 3 April 2024].

California Invasive Plant Council. 2023. Invasive Spartina Project. Website: https://www.cal-ipc.org/project/invasive-spartina-eradication/ [accessed December 2023].

Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J.M. Cooper, G.W. Kaiser, and M.C. E. McNall. 1990. The Birds of British Columbia, Volume 2. Diurnal Birds of Prey through Woodpeckers. Royal British Columbia Museum, Victoria, British Columbia. 636 pp.

Canadian Prairie Partners in Flight. 2004. Landbird conservation plan for Prairie Pothole Bird Conservation Region 11 in Canada. Canadian Wildlife Service, Edmonton, Alberta. 136 pp.

Cannings, R.J., pers. comm. 2023. In-person communication to L.K. Blight. August 2023. Member of Parliament, South Okanagan–West Kootenay, and Biologist. Penticton, British Columbia.

Cannings, R.J. 1999. Status of the Long-billed Curlew in British Columbia. British Columbia Wildlife Branch. 14 pp.

Carlisle, J., pers. comm. 2023. In-person communication to xx during threats call. March 2023. Research Director, Intermountain Bird Observatory, and Associate Research Professor, Department of Biological Sciences, Boise State University. Boise, Idaho.

Charlesworth, C., pers. comm. 2023. In-person communication to L.K. Blight. August 2023. Owner and Guide, Avocet Birding Tours, Kelowna, British Columbia.

Chesser, R.T., S.M. Billerman, K.J. Burns, C. Cicero, J.L. Dunn, B.E. Hernández-Baños, A.W. Kratter, I.J. Lovette, N.A. Mason, P.C. Rasmussen, J.V. Remsen, Jr., D.F. Stotz, and K. Winker. 2021. Check-list of North American Birds (online). American Ornithological Society. Website: http://checklist.aou.org/taxa [accessed January 2022].

Chu, P.C. 1995. Phylogenetic reanalysis of Strauch's osteological data set for the Charadriiformes. The Condor 97:174-196.

Coates, S.E. 2018. Building the full annual cycle picture for Long-Billed Curlews: correlates of nest success in the breeding grounds and spatial distribution and site fidelity in the wintering grounds. Ph.D. dissertation, Boise State University, Boise, Idaho. 114 pp. https://doi.org/10.18122/td/1375/boisestate

Coates, S., H. Hayes, and J. Carlisle. 2021. IBO Long-billed Curlew research and community education: 2021 status report. Intermountain Bird Observatory, Boise State University, Boise, Idaho. 46 pp.

Coates, S.E., B.W. Wright, and J.D. Carlisle. 2019. Long‐billed curlew nest site selection and success in the Intermountain West. The Journal of Wildlife Management, 83(5):1197-1213.

Cochrane, J.F., and S.H. Anderson. 1987. Comparison of habitat attributes at sites of stable and declining Long-billed Curlew populations. Great Basin Naturalist 47:459-466.

Colwell, M.A., and S.L. Dodd. 1995. Waterbird communities and habitat relationships in coastal pastures of northern California. Conservation Biology 9:827-834.

Colwell, M.A., and R.L. Mathis. 2001. Seasonal variation in territory occupancy of non-breeding Long-billed Curlews in intertidal habitats. Waterbirds 24:208-216.

Colwell, M.A., and K.D. Sundeen. 2000. Shorebird distributions on ocean beaches of northern California. Journal of Field Ornithology 71(1):1-15.

COSEWIC. 2002. COSEWIC assessment and status report on the Long-billed Curlew Numenius americanus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 31 pp.

COSEWIC. 2011. COSEWIC status appraisal summary on the Long-billed Curlew Numenius americanus in Canada. Ottawa. 17 pp.

Court, G., pers. comm. 2023. In-person communication to xx during threats call. March 2023. Provincial Wildlife Status Biologist, Alberta Ministry of Environment and Parks, Edmonton, Alberta.

Daehler, C.C., and D.R. Strong. 1996. Status, prediction and prevention of introduced cordgrass Spartina spp. invasions in Pacific estuaries, USA. Biological Conservation 78:51-58.

Dahl, T.E. 1990. Wetlands losses in the United States, 1780s to 1980s. Unpublished report. U.S. Department of the Interior, Fish and Wildlife Service, Washington, D.C., USA. iv + 13 pp.

Dale, B.C., P.S Taylor, and J.P. Goossen. 1999. Avifauna component report, Canadian Forces Base Suffield National Wildlife Area wildlife inventory. Canadian Wildlife Service, Environment Canada, Prairie and Northern Region, Edmonton, Alberta. 161 pp.

Danufsky, T. 2000. Winter shorebird communities of Humboldt Bay: species diversity, distributions, and habitat characteristics. Master's thesis, Humboldt State University, Arcata, California. 50 pp.

Davidson, P.J.A., R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (eds.). 2015. The Atlas of the Breeding Birds of British Columbia, 2008-2012. Bird Studies Canada, Delta, British Columbia. Website: http://www.birdatlas.bc.ca. [accessed January 2022].

Davidson, P.J.A., and N. Mahony. 2015. Long-billed Curlew. In P.J.A. Davidson, R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (eds.). The Atlas of the Breeding Birds of British Columbia, 2008-2012, Bird Studies Canada, Delta, British Columbia. Website: http://www.birdatlas.bc.ca/accounts/speciesaccount.jsp?sp=LBCU&lang=en [accessed January 2022]

Davis, C.A. 1996. Ecology of spring and fall migrant shorebirds in the Playa Lakes region of Texas. Ph.D. dissertation, Texas Tech University, Lubbock, Texas. 204 pp.

Davis, C.A., R.T. Churchwell, S.D. Fuhlendorf, D.M. Engle, and T.J. Hovick. 2016. Effect of pyric herbivory on source–sink dynamics in grassland birds. Journal of Applied Ecology 53:1004-1012.

Davis, S.K., S.M. Ludlow, and D.G. McMaster. 2016. Reproductive success of songbirds and waterfowl in native mixed-grass pasture and planted grasslands used for pasture and hay. The Condor 118(4):815-834. https://doi.org/10.1650/CONDOR-16-16.1

Day, J.H., and M.A. Colwell. 1998. Waterbird communities in rice fields subjected to different post-harvest treatments. Colonial Waterbirds 21:185-197.

Dechant, J.A., M.L. Sondreal, D.H. Johnson, L.D. Igl, C.M. Goldade, P.A. Rabie, and B.R. Euliss. 2001. Effects of management practices on grassland birds: Long-billed Curlew (Version 29FEB2000). Northern Prairie Wildlife Research Center, Jamestown, North Dakota. Website: https://www.usgs.gov/search?keywords=.+Effects+of+management+practices+on+grassland+birds%3B+Long-billed+Curlew [accessed October 2001].

De Smet, K.D. 1992. COSEWIC status report on the Long-billed Curlew Numenius americanus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 33 pp.

DeVries, J.H., S.O. Rimer, and E.M. Walsh. 2010. Cropland nesting by long-billed curlews in southern Alberta. Prairie Naturalist 42:123-129.

Dickson, R.D., and G.W. Beyersbergen. 1998. North America’s largest shorebird – have you seen it? Blue Jay 56:82-84.

Dugger, B.D., and K.M. Dugger. 2020. Long-billed Curlew (Numenius americanus), version 1.0. In A. F. Poole and F. B. Gill (eds.). Birds of the World, Cornell Lab of Ornithology, Ithaca, New York. Website: https://doi.org/10.2173/bow.lobcur.01 [accessed February 2022].

eBird. 2022. eBird: An online database of bird distribution and abundance [web application]. eBird, Cornell Lab of Ornithology, Ithaca, New York. Website: http://www.ebird.org [accessed February 2022].

Elliott, L., and K. McKnight. 2000. US Shorebird Conservation Plan: Lower Mississippi/Western Gulf Coast Shorebird planning region. Gulf Coastal Prairie Working Group and Mississippi Alluvial Valley/West Gulf Coastal Plain Working Groups, Corpus Christi, Texas. 64 pp.

Elphick, C.S. 2000. Functional equivalency between rice fields and seminatural wetland habitats. Conservation Biology 14:181-191.

Elphick, C.S., and L.W. Oring. 1998. Winter management of Californian rice fields for waterbirds. Journal of Applied Ecology 35:95-108.

Environment and Climate Change Canada. 2017. Action Plan for Multiple Species at Risk in Southwestern Saskatchewan: South of the Divide. Species at Risk Act Action Plan Series. Environment and Climate Change Canada, Ottawa. xi + 127 pp.

Environment Canada. 2013. Management Plan for the Long-billed Curlew (Numenius americanus) in Canada. Species at Risk Act Management Plan Series. Environment Canada, Ottawa. iii + 24 pp.

Federation of Alberta Naturalists. 2007. The Atlas of Breeding Birds of Alberta: A Second Look. Federation of Alberta Naturalists, Edmonton, Alberta. vii + 626 pp.

Fellows, S.D., and S.L. Jones. 2009. Status assessment and conservation action plan for the Long-billed Curlew (Numenius americanus). Biological Technical Publication FWS/BTP-R60122009. U.S. Department of Interior, Fish and Wildlife Service, Washington, D.C.

Fink, D., T. Auer, A. Johnston, M. Strimas-Mackey, S. Ligocki, O. Robinson, W. Hochachka, L. Jaromczyk, C. Crowley, K. Dunham, A. Stillman, I. Davies, A. Rodewald, V. Ruiz-Gutierrez, and C. Wood. 2023. eBird status and trends, data version: 2022; released: 2023. Cornell Lab of Ornithology, Ithaca, New York.

Forsythe, D.M. 1972. Observations on the nesting biology of the Long-billed Curlew. Great Basin Naturalist 32:88-90.

Frank, S.D., and J.F. Tooker. 2020. Neonicotinoids pose undocumented threats to food webs. Proceedings of the National Academy of Sciences 117:22609-22613. https://doi.org/10.1073/pnas.2017221117

Frenkel, R.E. 1987. Introduction and spread of cordgrass (Spartina) into the Pacific northwest. Northwest Environmental Journal 3:152-154.

Gayton, D. 2004. Native and non-native plant species in grazed grasslands of British Columbia’s southern interior. British Columbia Journal of Ecosystem Management 5:51-59.

Gerstenberg, R.H. 1979. Habitat utilization by wintering and migrating shorebirds on Humboldt Bay, California. Studies in Avian Biology 2:33-40.

Goater, C.P., and A.O. Bush. 1986. Nestling birds as prey of breeding Long-billed Curlews, Numenius americanus. Canadian Field Naturalist 100:263-264.

Godfrey, W.E. 1986. The Birds of Canada, revised edition. National Museum of Canada, Ottawa, Ontario. 595 pp.

Government of Canada. 2021. Breeding Bird Survey Overview. Website: https://www.Canada.ca/en/environment-climate-change/services/bird-surveys/landbird/north-american-breeding/overview.html [accessed March 2022].

Government of Canada. 2023. Habitat Stewardship Program for Species at Risk. Website: https://www.Canada.ca/en/environment-climate-change/services/environmental-funding/programs/habitat-stewardship-species-at-risk.html#toc4 [accessed December 2023].

Government of Saskatchewan. 2021. Helium Action Plan. Website: https://www.Saskatchewan.ca/helium-action-plan [accessed March 2023].

Grant, M.C. 1991. Relationships between egg size, chick size at hatching, and chick survival in the Whimbrel Numenius phaeopus. Ibis 133:127-133.

Grasslands Conservation Council of British Columbia. 2004. British Columbia grasslands mapping project: a conservation risk assessment, final report. Grasslands Conservation Council of British Columbia, Kamloops, British Columbia. 108 pp.

Graul, W.D. 1971. Observations at a Long-billed Curlew nest. The Auk 88:182-184.

Hartman, C. A., and L.W. Oring. 2009. Reproductive success of Long-billed Curlews (Numenius americanus) in northeastern Nevada hay fields. The Auk 126:420-430.

Hooper, T.D., and M.D. Pitt. 1996. Breeding bird communities and habitat associations in the grasslands of the Chilcotin Region, British Columbia. FRDA Report 243. Canadian Forest Service and British Columbia Ministry of Forests, Victoria, British Columbia.

Hunter, W.C., J.A. Collazo, R. Noffsinger, B. Winn, D. Allen, B. Harrington, M. Epstein, and J. Saliva. 2007. Southeastern Coastal Plains-Caribbean Region Report: U.S. Shorebird Conservation Plan. U.S. Fish and Wildlife Service, Atlanta, Georgia. 46 pp.

Jenni, D.A., R L. Redmond, and T.K. Bicak. 1981. Behavioral ecology and habitat relationships of Long-billed Curlew in western Idaho. Bureau of Land Management, Boise District, Idaho. 22 pp.

Jones, C. 2021. Volunteer Long-billed Curlew survey, Cariboo Region, May 2021. British Columbia Ministry of Forests, Lands, Natural Resource Operations and Rural Development, Victoria, British Columbia. 9 pp.

Jones, S.L., C.S. Nations, S.D. Fellows, and L.L. McDonald. 2008. Breeding abundance and distribution of Long-billed Curlews (Numenius americanus) in North America. Waterbirds 31(1):1-14.

Johnsgard, P.A. 1981. The Plovers, Sandpipers, and Snipes of the World. University of Nebraska Press, Lincoln, Nebraska. 519 pp.

Johnson, D., pers. comm. 2001. In-person communication to xx. November 2001. Research Scientist, Land Resource Sciences Section, Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta. Cited in COSEWIC 2002.

Katzner, T.E., J.D. Carlisle, S.A. Poessel, E.C. Thomason, B.P. Pauli, D.S. Pilliod, J.R. Belthoff, J.A. Heath, K.J. Parker, K.S. Warner, and H.M. Hayes. 2020. Illegal killing of nongame wildlife and recreational shooting in conservation areas. Conservation Science and Practice 2(11):e279.

Kennish, M.J. 2001. Coastal salt marsh systems in the U.S.: a review of anthropogenic impacts. Journal of Coastal Research 17:731-749.

King, R. 1978. Habitat use and related behaviors of breeding Long-billed Curlews. Master's thesis, Colorado State University, Fort Collins, Colorado. 69 pp.

Koes, R. 2001. eBird Checklist. https://ebird.org/checklist/S90066942. eBird: An online database of bird distribution and abundance [web application]. eBird, Ithaca, New York. Website: http://www.ebird.org [accessed 29 March 2024].

Kuehl, A.K., and W.R. Clark. 2002. Predator activity related to landscape features in northern Iowa. The Journal of Wildlife Management 66:1224-1234.

Lea, T. 2008. Historical (pre-settlement) ecosystems of the Okanagan Valley and Lower Similkameen Valley of British Columbia – pre-European contact to the present. Davidsonia 19:3-36.

Leeman, L.W., M.A. Colwell, T.S. Leeman, and R.L. Mathis. 2001. Diets, energy intake, and kleptoparasitism of nonbreeding Long-billed Curlews in a northern California estuary. Wilson Bulletin 113:196-203.

Leeman, T.S. 2000. Importance of coastal pastures to Long-billed Curlews (Numenius americanus). Master's thesis, Humboldt State University, Arcata, California.

Li, Y., R. Miao, and M. Khanna. 2020. Neonicotinoids and decline in bird biodiversity in the United States. Nature Sustainability 3:1027-1035.

Mader, H.J. 1984. Animal habitat isolation by roads and agricultural fields. Biological Conservation 29:81-96.

Maher, W.J. 1973. Matador Project: Birds I. Population dynamics. Canadian Committee for the International Biological Programme, Matador Project, Technical Report 34. University of Saskatchewan, Saskatoon, Saskatchewan. 56 pp.

Mann, M.L., P. Berck, M.A. Moritz, E. Batllori, J.G. Baldwin, C.K. Gately, and D.R. Cameron. 2014. Modeling residential development in California from 2000 to 2050: Integrating wildfire risk, wildland and agricultural encroachment. Land Use Policy 41:438-452.

Manzano-Fischer, P., R. List, and G. Ceballos. 1999. Grassland birds in prairie-dog towns in northwestern Chihuahua, Mexico. Studies in Avian Biology 19:263-271.

Marks, J.S. 1992. Longevity record for the Bristle-thighed Curlew: an extension. Journal of Field Ornithology 63:309-310.

Martin, T.E. 1987. Food as a limit on breeding birds: a life-history perspective. Annual review of ecology and systematics 18(1):453-487.

Master, L.L., D. Faber-Langendoen, R. Bittman, G.A. Hammerson, B. Heidel, L. Ramsay, K. Snow, A. Teucher, and A. Tomaino. 2012. NatureServe conservation status assessments: factors for evaluating species and ecosystems risk. NatureServe, Arlington, Virginia. 64 pp.

Mathis, R.L. 2000. Analysis of Long-billed Curlews (Numenius americanus) distributions at three special scales. Master's thesis, Humboldt State University, Arcata, California. 52 pp.

McLay, A.S., and D.E. Cole. 1995. Biological control of leafy spurge in Alberta: progress and prospects. AECV95-R2. Alberta Environmental Centre, Vegreville, Alberta. 63 pp.

Mitsch, W.J., and M.E. Hernandez. 2013. Landscape and climate change threats to wetlands of North and Central America. Aquatic Science 75:133-149.

National Audubon Society. 2019. The Audubon Birds and Climate Change Report. Website: https://climate2014.audubon.org/birds/lobcur/long-billed-curlew [accessed January 2022].

NatureCounts. 2024. NatureCounts platform. Website: https://naturecounts.ca [accessed 26 February 2024].

NatureServe. 2024. NatureServe Explorer. Website:https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.100438/Numenius_americanus [accessed April 2024].

Navedo, J.G., L. Sauma-Castillo, and G. Fernández, 2012. Foraging activity and capture rate of large Nearctic shorebirds wintering at a tropical coastal lagoon. Waterbirds 35:301-311.

Nernberg, D., and D. Ingstrup. 2005. Prairie conservation in Canada: The Prairie Conservation Action Plan experience. Pp. 478-484 in C. J. Ralph and T. D. Rich (eds.). Bird Conservation Implementation and Integration in the Americas: Proceedings of the Third International Partners in Flight Conference, Asilomar, California. U.S. Dept. of Agriculture, Forest Service, Pacific Southwest Research Station, Davis, California.

Ng, J., M.D. Giovanni, M.J. Bechard, J.K. Schmutz, and P. Pyle. 2020. Ferruginous Hawk (Buteo regalis), version 1.0. In P.G. Rodewald (ed.). Birds of the World, Cornell Lab of Ornithology, Ithaca, New York. Website: https://doi.org/10.2173/bow.ferhaw.01 [accessed February 2022].

Ohanjanian, I.A. 1985. The Long-billed Curlew, Numenius americanus, on Skookumchuck Prairie: status report and enhancement plan. B.C. Fish and Wildlife Branch, Cranbrook, BC. 52 pp.

Ohanjanian, I.A. 1986. The Long-billed Curlew in the East Kootenay: status report and enhancement schedule for Skookumchuck Prairie. B.C. Fish and Wildlife Branch, Cranbrook, British Columbia. 24 pp.

Ohanjanian, I.A. 1992. Numbers, distribution and habitat dynamics of Long-billed Curlews in the East Kootenay. Wildlife Branch, B.C. Environment, Cranbrook, British Columbia. 41 pp.

Ohanjanian, I.A. 2004. Long-billed Curlew: Accounts and Measures for Managing Identified Wildlife-Accounts. V. 2004. British Columbia Ministry of the Environment. 8 pp.

Olalla-Kerstupp, A., G. Ruiz-Aymá, A. Guzmán-Velasco, and J.I. González-Rojas. 2020. Winter diet and prey availability of the Long-billed Curlew (Numenius americanus) in the Chihuahuan Desert, Mexico. Natural Areas Journal 40:228-236.

Ott, J.P., B.B. Hanberry, M. Khalil, M.W. Paschke, M.P. Van Der Burg, and A.J. Prenni. 2021. Energy development and production in the Great Plains: implications and mitigation opportunities. Rangeland Ecology and Management 78:257-272.

Page, G., L.E. Stenzel, and C.M. Wolfe. 1979. Aspects of the occurrence of shorebirds on a central California estuary. Studies in Avian Biology 2:13-32.

Pampush, G.J. 1981. Breeding chronology, habitat utilization, and nest site selection of the Long-billed Curlew in northcentral Oregon. Master's thesis, Oregon State University, Corvallis, Oregon. 49 pp.

Pampush, G.J., and R.G. Anthony. 1993. Nest success, habitat utilization and nest-site selection of Long-billed Curlews in the Columbia Basin, Oregon. Condor 95:957-967.

Paton, P.W., and J. Dalton. 1994. Breeding ecology of long-billed curlews at Great Salt Lake, Utah. The Great Basin Naturalist 54(1):79-85.

Pietrzak, D., J. Kania, E. Kmiecik, G. Malina, and K. Wątor. 2020. Fate of selected neonicotinoid insecticides in soil–water systems: current state of the art and knowledge gaps. Chemosphere 255:126981. https://doi.org/10.1016/j.chemosphere.2020.126981

Pinel, H.W., W.W. Smith, and C.R. Wershler. 1991. Alberta Birds, 1971 to 1980. Provincial Museum of Alberta Natural History Occasional Paper No. 13. 243 pp.

Poole., T., pers. comm. 2024. Email correspondence to L.K. Blight. March 2024. Zoology Conservation Manager (Acting), Habitat and Endangered Species Section, Wildlife Branch, Ministry of Natural Resources and Northern Development, xxx, Manitoba.

Prairie Habitat Joint Venture. 2021. Prairie Habitat Joint Venture implementation plan 2021-2025: the Prairie Parklands. Report of the Prairie Habitat Joint Venture. Environment Canada, Edmonton, AB. ii + 98 pp. Website: https://phjv.ca/wp-content/uploads/2023/07/PHJV-Implementation-Plan-PRAIRIE-PARKLAND-2021-2025-FINAL-May-25-2022.pdf

Prescott, D.R.C., and L. Bilyk. 1996. Avian communities and NAWMP habitat priorities in the southern Prairie biome of Alberta. NAWMP-026. Alberta NAWMP Centre and Land Stewardship Centre of Canada, Edmonton, Alberta. 43 pp.

Price, J.T. 1995. Potential impacts of global climate change on the summer distribution of some North American grassland birds. Ph.D. dissertation, Wayne State University, Detroit, Michigan. 180 pp.

Put, J., pers. comm. 2023. Review comment to D. Bradley and R. Torrenta. August 2023. Resource Management Officer, Parks Canada, Grasslands National Park, Val Marie, Saskatchewan.

Ramirez Jr., P. 2010. Bird mortality in oil field wastewater disposal facilities. Environmental Management 46:820-826.

Redmond, R.L., and D.A. Jenni. 1982. Natal philopatry and breeding area fidelity of Long-billed Curlews (Numenius americanus): patterns and evolutionary consequences. Behavioral Ecology and Sociobiology 10:277-279.

Redmond, R.L., and D.A. Jenni. 1986. Population ecology of the Long-billed Curlew (Numenius americanus) in western Idaho. Auk 103:755-767.

Renaud, W.E. 1980. Long-billed Curlew in Saskatchewan: status and distribution. Blue Jay 38:221-237.

Roy, J.F. 1996. Birds of the Elbow. Manley Callin Series No. 3. Saskatchewan Natural History Society, Nature Saskatchewan, Regina, Saskatoon. 325 pp.

Sadler, D.A.R., and W.J. Maher. 1976. Notes on the Long-billed Curlew in Saskatchewan. The Auk 93:382-384.

Salafsky, N., D. Salzer, A.J Stattersfield, C. Hilton‐Taylor, R. Neugarten, S.H. Butchart, B. Collen, N. Cox, L.L. Master, S. O'Connor, and D. Wilkie. 2008. A standard lexicon for biodiversity conservation: unified classifications of threats and actions. Conservation Biology 22:897-911.

Samson, F.B., F.L. Knopf, and W.R. Ostlie. 2004. Great Plains ecosystems: past, present and future. Wildlife Society Bulletin 32:6-15.

Saunders, E.J. 2001. Population estimate and habitat associations of the Long-billed Curlew (Numenius americanus) in Alberta. Alberta Species at Risk Report No. 25. Alberta Sustainable Resource Development, Fish and Wildlife Division, Lethbridge, Alberta. 58 pp.

Schwemmer, P., R. Pederson, K. Haecker, P. Bocher, J. Fort, M. Mercker, F. Jiguet, J. Elts, R. Marja, M. Piha, P. Rousseau, and S. Garthe. 2022. Assessing potential conflicts between offshore wind farms and migration patterns of a threatened shorebird species. Animal Conservation 26(3):303-316. https://doi.org/10.1111/acv.12817

Selleck, G.W., R.T. Coupland, and C. Frankton. 1962. Leafy spurge in Saskatchewan. Ecological Monographs 32:1-29. https://library.ndsu.edu/ir/bitstream/handle/10365/3208/620sel62.pdf;jsessionid=FE2442107EE70931E68BE3A109F54D96?sequence=1

Sesser, K.A. 2013. Habitat and space use by Long-billed Curlews (Numenius americanus) in California’s Central Valley. Master's thesis, Humboldt State University, California. 57 pp.

Shackford, J.S. 1994. Nesting of Long-billed Curlews on cultivated fields. Bulletin of the Oklahoma Ornithological Society 27:17-20.

Shuford, W.D., G.W. Page, and J.E. Kjelmyr. 1998. Patterns and dynamics of shorebird use of California's Central Valley. The Condor 100:227-244.

Smith, A.C., M-A.R. Hudson, V.I. Aponte, and C.M. Francis. 2023. North American Breeding Bird Survey - Canadian Trends Website, Data-version 2021. Environment and Climate Change Canada, Gatineau, Quebec

Smith, A.R. 1996. Atlas of Saskatchewan Birds. Saskatchewan Natural History Society Special Publications 22, Regina, Saskatchewan. 456 pp.

Sólymos, P., S. M. Matsuoka, E. M. Bayne, S. R. Lele, P. Fontaine, S. G. Cumming, D. Stralberg, F. K. A. Schmiegelow, S. J. Song, and R. B. O’Hara. 2013. Calibrating indices of avian density from non-standardized survey data: making the most of a messy situation. Methods in Ecology and Evolution 4:1047-1058.

Stanley, T.R., and S.K. Skagen. 2007. Estimating the breeding population of long‐billed curlew in the United States. The Journal of Wildlife Management 71:2556-2564.

Stenzel, L.E., H.R. Huber, and G.W. Page. 1976. Feeding behavior and diet of the Long-billed Curlew and Willet. Wilson Bulletin 88:314-332.

Stocking, J., E. Elliott-Smith, N. Holcomb, and S.M. Haig. 2010. Long-billed curlew breeding success on Mid-Columbia River National Wildlife Refuges, south-central Washington and north-central Oregon, 2007 to 2008. U.S. Geological Survey Open-File Report 2010-1089. U.S. Geological Service, Reston, Virginia. 40 pp.

Strang, R.M., and J.V. Parminter. 1980. Conifer encroachment on the Chilcotin grasslands in British Columbia. Forest Chronicles 56:13-18.

Sugden, J.W. 1933. Range restriction of the Long-billed Curlew. The Condor 35:3-9.

Taft, O.W., and S.M. Haig. 2003. Historical wetlands in Oregon’s Willamette Valley: Implications for restoration of winter waterbird habitat. Wetlands 23:51-64.

Thompson, E.E. 1891. The Birds of Manitoba. Proceedings of the United States National Museum 13:457-643.

Timken, R.L. 1969. Notes on the Long-billed Curlew. The Auk 86:750-751.

Tostain, O., J.L. Dujardin, C. Érard, and J.M. Thiollay. 1992. Oiseaux de Guyanne. Société d’études ornithologiques, Brunoy, France. 224 pp.

Turner, J.S., and P.G. Krannitz. 2001. Conifer density increases in semi-desert habitats of British Columbia in the absence of fire. Northwest Science 75:176-182.

van de Ven, T.M.F.N., A.E. McKechnie, S. Er, and S.J. Cunningham. 2020. High temperatures are associated with substantial reductions in breeding success and offspring quality in an arid-zone bird. Oecologia 193:225-235.

Van Spall, K., and J. Steciw. 2004. Volunteer Long-billed Curlew survey, May 2004, Cariboo-Chilcotin Region. British Columbia Ministry of Water, Land and Air Protection. 10 pp.

Vegetation Resources Inventory (VRI). 2021. B.C. Forest Inventory. Website: https://www2.gov.bc.ca/gov/content/industry/forestry/managing-our-forest-resources/forest-inventory [accessed September 2022].

Warnock, N., pers. comm. 2023. In-person communication to xx during threats call. March 2023. Director of Conservation Science, Audubon Canyon Ranch, Stinson Beach, California.

Warnock, N., S.M. Haig, and L.W. Oring. 1998. Monitoring species richness and abundance of shorebirds in the western Great Basin. The Condor 100:589-600.

Watmough, M.D., and M.J. Schmoll. 2007. Environment Canada’s Prairie and Northern Region Habitat Monitoring Program Phase II. Recent habitat trends in the Prairie Habitat Joint Venture. Technical Report Number 493. Environment Canada, Canadian Wildlife Service, Edmonton, Alberta. 135 pp.

Watmough, M.D., Z. Li, and E.M. Beck. 2017. Prairie Habitat Monitoring Program Canadian Prairie Wetland and Upland Status and Trends 2001 to 2011 in the Prairie Habitat Joint Venture Delivery Area. Prairie Habitat Joint Venture, Edmonton, Alberta. 100 pp.

Webb, D.R. 1987. Thermal tolerance of avian embryos: a review. Condor 89:874-898.

Wolfe, L.R. 1931. The breeding Limicolae of Utah. The Condor 33(2):49-59.

Collections examined

No collections were examined for the preparation of this report.

Authorities contacted

• Benville, A. Data Manager, Saskatchewan Conservation Data Centre. Regina, Saskatchewan
• Bilyk, L. Resource Data Biologist, Alberta Environment and Parks. Edmonton, Alberta
• Buell, D. Land Administrator – Habitat, Wildlife and Access. Brooks, Alberta
• Carlisle, J. Research Director, Intermountain Bird Observatory. Associate Research Professor, Department of Biological Sciences, Boise State University. Boise, Idaho
• Court, G. Provincial Wildlife Status Biologist, Alberta Ministry of Environment and Parks. Edmonton, Alberta
• Davis, S. Wildlife Biologist, Canadian Wildlife Service, Environment and Climate Change Canada. Regina, Saskatchewan
• Downey, B. Program Manager, Alberta Ministry of Environment and Parks. Edmonton, Alberta
• Fisher, R. Curator of Vertebrate Zoology, Royal Saskatchewan Museum. Regina, Saskatchewan
• Hentze, N. Zoologist, BC Conservation Data Centre. Victoria, British Columbia
• Johnson, D. Professor, University of Lethbridge. Lethbridge, Alberta
• Jones, C. Wildlife Biologist, Ministry of Forests, Lands and Natural Resource Operations. Duncan, British Columbia
• Keith, J. Biodiversity Biologist, Saskatchewan Ministry of Environment. Regina, Saskatchewan
• Luszcz, T. Species at Risk Monitoring Biologist, Canadian Wildlife Service, Environment and Climate Change Canada. Penticton, British Columbia
• Robinson, B. Wildlife Biologist, Environment and Climate Change Canada. Edmonton, Alberta
• Warnock, N. Director of Conservation Science. Audubon Canyon Ranch, Stinson Beach, California

Acknowledgements

Funding for the preparation of this report was provided by Environment and Climate Change Canada. The authorities listed above provided valuable data and/or advice.

The report writers would also like to thank previous report writers Ken De Smet, Liz Saunders, Deborah Perkins and Cheri Gratto-Trevor, as well as Richard Cannings, Penny Ohanjanian, Barry Robinson and the many citizen scientists who provided records through eBird and the provincial bird atlases. The report writers would also like to acknowledge the various contacts we have made in British Columbia, Alberta and Saskatchewan, who have provided the data and analyses used in this report. Finally, the report writers would like to thank the COSEWIC Birds Specialist Sub-committee (SSC) Co-chairs Marcel Gahbauer and Louise Blight, and the SSC report reviewers (Paul Allen Smith, Ann McKellar and Tara Imlay).

Biographical summary of report writers

David Bradley has a Ph.D. in Behavioural Ecology involving research on an endangered endemic bird species in New Zealand. He has also conducted research on Long-billed Curlew, specifically tracking the species’ migration from its breeding grounds in British Columbia, and works on improving land stewardship to enhance conservation of this species. David is currently the Director of the British Columbia office at Birds Canada, and has a strong interest in protecting at-risk birds through increased understanding of threat mitigation.

Rémi Torrenta is a Wildlife Ecologist with a Ph.D. in bird ecology and conservation. He is the British Columbia Projects Coordinator at Birds Canada. Rémi has been involved in avian research for the past 10 years, with species and projects across North America, and has been particularly focused on the influence of changes in landscape structure on forest birds. He is interested in understanding the effects of anthropogenic disturbances on populations and communities in order to improve the establishment of conservation planning targets, and is convinced that conservation goals are better achieved through public education and citizen science programs.

Appendix 1. Threats calculator table for Long-billed Curlew.

Species scientific name: Long-billed Curlew

Date: 15 March 2023

Assessor(s): David Bradley, Rémi Torrenta, Christian Artuso, Louise Blight, Jay Carlisle, Gordon Court, Richard Elliot, Danielle Ethier, Robin Gutsell, Nathan Hentze, Jennifer Heron, Elsie Krebs, Ann McKellar, Stefano Liccioli, Janet Ng, Jeanette Pepper, Amit Saini, Julie Steciw, Nils Warnock.

Assigned overall threat impact:

BC = High - Medium. Given the recent increase in the rate of decline, it seems plausible that some threats were underscored here.

Classification of Threats adopted from IUCN–CMP, Salafsky et al. (2008).