Mountain Plover (Charadrius montanus): COSEWIC rapid review of classification 2021

Official title: COSEWIC Rapid Review of Classification on the Mountain Plover (Charadrius montanus) in Canada

Committee on the Status of Endangered Wildlife in Canada (COSEWIC)
Endangered 2021

COSEWIC assessment summary

Assessment summary – November 2021

Common name: Mountain Plover

Scientific name: Charadrius montanus

Status: Endangered

Reason for designation: This shorebird of shortgrass prairies reaches the northern limits of its breeding distribution in extreme southern Alberta and Saskatchewan. It has become exceedingly rare in Canada, with no observations since 2012, although small numbers may persist in areas with little survey effort. Historically, the population is believed to have declined primarily as a result of habitat loss from agricultural intensification and fire suppression. Temperature extremes and changes to habitat related to climate change are also of concern. Immigration from outside Canada is unlikely, because the nearest potential source population in Montana is also small and declining.

Occurrence: Alberta, Saskatchewan

Status history: Designated Endangered in April 1987. Status re-examined and confirmed in November 2000, November 2009, and December 2021.

COSEWIC rapid review of classification

Preface

Since the previous status report (COSEWIC 2009), there has been little evidence of Mountain Plover occurrence in Canada. No formal surveys have been conducted for the species, but it is highly sought after by birders, so there has likely been some search effort in accessible portions of the historical Canadian range. eBird (2021), an online database of sightings that has gained widespread use by birders, shows only one sighting in Canada since the previous status report, barely north of the United States border near Onefour, Alberta in 2012. No other recent observations have been reported in Alberta (Court pers. comm. 2020; Gutsell pers. comm. 2020; Knapton pers. comm. 2020), and in Saskatchewan, the first four years of the provincial breeding bird atlas have not yet yielded any reports of Mountain Plover.

A Recovery Strategy exists for the species, but neither it nor the previous status report includes a formal threat assessment (Environment Canada 2006; COSEWIC 2009). The South of the Divide Action Plan (Environment and Climate Change Canada 2016) details ongoing and recommended conservation actions targeting this and other prairie species in southwestern Saskatchewan, mainly following from their respective recovery plans. Mountain Plover is not listed under the United States Endangered Species Act, but is nevertheless a focus of habitat conservation and management efforts in that country (Shaffer et al. 2019), because of its long-term declines, restricted distribution, and status as an indicator species (Dinsmore et al. 2010).

Status history

Designated Endangered in April 1987. Status re-examined and confirmed in November 2000, November 2009, and December 2021.

Updated map

Not required, as no change in distribution is known; see previous assessment (COSEWIC 2009).

Technical summary

Charadrius montanus
Mountain Plover
Pluvier montagnard
Range of occurrence in Canada (province/territory/ocean): Alberta, Saskatchewan

Demographic information

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

Approximately 4 years, based on IUCN estimate (Bird et al. 2020).

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

Unknown; insufficient search effort to determine whether population size has changed, although likely too few individuals to estimate.

Estimated 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]

Unknown; insufficient search effort to determine whether population size has changed.

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

Unknown; insufficient search effort to determine whether population size has changed.

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

Unknown; population size too small for meaningful or reliable predictions to be made.

[Observed, estimated, inferred, 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.

Unknown; population size too small for meaningful or reliable predictions to be made.

Are the causes of the decline clearly understood?

Yes, long-term loss of shortgrass prairie in Canada (COSEWIC 2009) and United States.

Have the causes of the decline ceased?

No, shortgrass prairie remains under threat (Wilsey et al. 2019)

Are the causes of the decline clearly reversible?

Yes, possible via management practices, such as conservation grazing (Shaffer et al. 2019), if also applied to source population in United States.

Are there extreme fluctuations in number of mature individuals?

No

Extent and occupancy information

Estimated extent of occurrence (EOO)

0-3030 km²; upper limit based on minimum convex polygon around known occurrences as of COSEWIC (2009), but species has been reported only once in Canada since then, so current EOO is almost certainly much smaller.

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

0-24 km²; upper limit based on 2x2 km grid over sites with breeding records reported in COSEWIC (2009)

Is the population “severely fragmented” i.e., is >50% of its total area of occupancy in habitat patches that are (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?

a. No
b. No

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

Unknown, but almost certainly <5 given the small population size.

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

Unknown; insufficient recent observations to revise estimate.

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

Unknown; insufficient recent observations to revise estimate.

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

n/a (only one population).

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

Unknown

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

Yes, observed continuing declines in extent and quality of shortgrass prairie, especially via conversion of pastureland to cropland (Wilsey et al. 2019)

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

^* See Definitions and Abbreviations on COSEWIC website and IUCN for more information on this term.

Number of mature individuals (in each subpopulation)

Subpopulations total (one subpopulation): N Mature Individuals (give plausible ranges) Range of 0-11 recorded in any one year; upper limit based on COSEWIC (2009), but likely closer to the lower limit given only one record of a mature individual in Canada since then, in 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? No, threats were previously only listed in Environment Canada (2006) and COSEWIC (2009)

Key threats identified in the previous status report (COSEWIC 2009; with impact inferred here from the wording of that text) can be classified as:

• IUCN 2 (Agriculture and aquaculture): habitat loss and degradation to annual and perennial non-timber crops (2.1) and livestock farming and ranching (2.3) (High)
• IUCN 7 (Natural system modifications): habitat loss to fire and fire suppression (7.1) and other ecosystem modifications [loss of native herbivores] (7.3) (High)
• IUCN 11 (Climate change and severe weather): mortality and habitat loss from temperature extremes (11.3) (Medium-Low)
• IUCN 9 (Pollution): mortality from agricultural effluents (9.3) (Unknown)

What additional limiting factors are relevant? Strong dependence on short vegetation and bare ground, maintained by native herbivorous mammals or farming and ranching activities that replicate their effects (COSEWIC 2009)

Rescue effect (natural immigration from outside Canada)

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

Rare and declining; nearest outside population (in Montana) is disjunct from main range (Wyoming and farther south), has had no detections on Breeding Bird Survey routes since 1996 (Sauer et al. 2017), and no breeding individuals reported to Montana Natural Heritage Program since 2015 (down from >100 per year prior to 2009; Montana Natural Heritage Program 2020), although an adult was observed with two recently fledged young at Snake Butte Prairie Dog Complex in 2021, approximately 75 km south of the Canada border (eBird 2021).

Is immigration known or possible?

Yes, Montana is likely the main source of Canada’s birds (Environment Canada 2006).

Would immigrants be adapted to survive in Canada?

Yes, species is known to have bred in Canada.

Is there sufficient habitat for immigrants in Canada?

Yes.

Are conditions deteriorating in Canada?⁺

Yes, habitat subject to multiple threats (COSEWIC 2009).

Are conditions for the source (i.e., outside) population deteriorating?⁺

No, habitat conditions thought to be stable (U.S. Fish and Wildlife Service 2011).

Is the Canadian population considered to be a sink?⁺

Unknown.

Is rescue from outside populations likely?

No, habitat is available in Canada, but its quality is deteriorating, and the source population is small and declining (Sauer et al. 2017).

⁺ See Table 3 (Guidelines for modifying status assessment based on rescue effect).

Occurrence data sensitivity

Are occurrence data of this species sensitive? No

Status history

COSEWIC: Designated Endangered in April 1987. Status re-examined and confirmed in November 2000, November 2009, and December 2021.

Status and reasons for designation

Status: Endangered

Alpha-numeric codes: D1

Reasons for designation: This shorebird of shortgrass prairies reaches the northern limits of its breeding distribution in extreme southern Alberta and Saskatchewan. It has become exceedingly rare in Canada, with no observations since 2012, although small numbers may persist in areas with little survey effort. Historically, the population is believed to have declined primarily as a result of habitat loss from agricultural intensification and fire suppression. Temperature extremes and changes to habitat related to climate change are also of concern. Immigration from outside Canada is unlikely, because the nearest potential source population in Montana is also small and declining.

Applicability of criteria

Criterion A (Decline in Total Number of Mature Individuals): Not applicable. Insufficient data to reliably infer, project, or suspect population trends.

Criterion B (Small Distribution Range and Decline or Fluctuation): May meet Endangered, B1ab(iii) and B2ab(iii). Maximum EOO of 3030 km² and IAO of 24 km² are below thresholds, but while number of locations is unknown but likely fewer than five, it is unclear whether ongoing decline in habitat availability is influencing current status, given that the population is already at or near zero.

Criterion C (Small and Declining Number of Mature Individuals): Not applicable. Number of mature individuals (0-11) is below the threshold for Endangered. However, data are insufficient to observe, project, or infer a continuing decline in number of mature individuals.

Criterion D (Very Small or Restricted Population): Meets Endangered, D1. Number of mature individuals estimated to be 0-11.

Criterion E (Quantitative Analysis): Analysis not conducted.

Acknowledgements

Funding for the preparation of this report was provided by Environment and Climate Change Canada. The authorities listed below provided valuable data and/or advice. Data and advice from Richard Knapton, a co-writer of the previous status report, were particularly helpful.

Authorities contacted

Court, G. Provincial Wildlife Status Biologist, Fish and Wildlife Management, Alberta Environment and Parks, Edmonton, Alberta.

Fisher, R. Curator of Vertebrate Zoology, Royal Saskatchewan Museum, Regina, Saskatchewan.

Gutsell, R. Wildlife Status Biologist, Fish and Wildlife Management, Alberta Environment and Parks, Edmonton, Alberta.

Keith, J. Coordinator, Saskatchewan Conservation Data Centre, Fish, Wildlife and Lands Branch, Saskatchewan Ministry of Environment, Regina, Saskatchewan.

Knapton, R. Biologist, Ottawa, Ontario.

Pietro Diaz, B. Terrestrial Ecologist, Habitat Unit, Fish, Wildlife and Lands Branch, Saskatchewan Ministry of Environment, Regina, Saskatchewan.

Information sources

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

Birds Canada. 2021. Saskatchewan Breeding Bird Atlas. Website: Saskatchewan Breeding Bird Atlas [accessed July 2021].

Carlisle, J.D, A.D. Chalfoun, K.T. Smith, and J.L. Beck. 2018. Nontarget effects on songbirds from habitat manipulation for Greater Sage-Grouse: implications for the umbrella species concept. Condor: Ornithological Applications 120:439-455.

COSEWIC. 2009. Update COSEWIC Status Report on Mountain Plover (Charadrius montanus). Committee on the Status of Endangered Wildlife in Canada. Ottawa, Ontario.

Court, G., pers. comm. 2020. Email correspondence to A.G. Horn. July 2020. Provincial Wildlife Status Biologist. Fish and Wildlife Management, Alberta Environment and Parks, Edmonton, Alberta.

Dinsmore, S.J., M.B. Wunder, V.J. Dreitz, and F.L. Knopf. 2010. An assessment of factors affecting population growth of the Mountain Plover. Avian Conservation and Ecology 5:5. Website: [accessed October 2020].

eBird. 2021. eBird: An online data base of bird distribution and abundance [web application]. eBird, Ithaca, New York. Website: [accessed October 2021].

Environment Canada. 2006. Recovery Strategy for the Mountain Plover (Charadrius montanus) in Canada. Species at Risk Act Recovery Strategy Series. Environment Canada, Ottawa. iv + 16pp.

Environment and Climate Change Canada. 2016. Action Plan for Multiple Species at Risk in Southwestern Saskatchewan: South of the Divide [Proposed]. Species at Risk Act Action Plan Series. Environment and Climate Change Canada, Ottawa, Ontario. xi + 127 pp.

Gutsell, R., pers. comm. 2020. Email correspondence to A.G. Horn. July 2020. Wildlife Status Biologist, Fish and Wildlife Management, Alberta Environment and Parks, Edmonton, Alberta.

Knapton, R., pers. comm. 2020. Email correspondence to A.G. Horn. July 2020. Independent biologist.

Montana Natural Heritage Program. 2020. Mountain Plover — Charadrius montanus. Montana Field Guide. Montana Fish, Wildlife and Parks. Website: [accessed December 2020].

Pardieck, K.L., D.J. Ziolkowski Jr., M. Lutmerding, V.I. Aponte, and M-A.R. Hudson. 2020. North American Breeding Bird Survey Dataset 1966 - 2019: U.S. Geological Survey data release. Website: [accessed December 2020].

Sauer, J.R., D.K. Niven, J.E. Hines, D.J. Ziolkowski, Jr., K.L Pardieck, J.E. Fallon, and W.A. Link. 2017. The North American Breeding Bird Survey, Results and Analysis 1966-2015. Version 02.07.2017. USGS Patuxent Wildlife Research Center, Laurel, Maryland.

Shaffer, J.A., L.D. Igl, D.H. Johnson, M.L. Sondreal, C.M. Goldade, M.P. Nenneman, T.L. Wooten, and B.R. Euliss. 2019. The effects of management practices on grassland birds—Mountain Plover (Charadrius montanus). U.S. Geological Survey Professional Paper 1842. Website: [accessed October 2020].

U.S. Fish and Wildlife Service. 2011. Fish and Wildlife Service determines the Mountain Plover does not warrant protection under the Endangered Species Act [press release]. U.S. Fish and Wildlife Service, Mountain-Prairie Region, Lakewood, Colorado. PDF: https://www.fws.gov/mountain-prairie/es/species/birds/mountainplover/PressRelease05112011.pdf [accessed October 2020]. (presently not an active link)

Wilsey, C.B., J. Grand, J. Wu, N. Michel, J. Grogan-Brown, and B. Trusty. 2019. North American grasslands and birds report. National Audubon Society, New York, New York. 57 pp.

Writer of rapid review of classification

Andrew G. Horn

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 (2021)

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.