Recovery Strategy for the Least Bittern (Ixobrychus exilis) in Canada - 2014
- Preface
- Acknowledgements
- Executive Summary
- Recovery Feasibility Summary
- 1. COSEWIC Species Assessment Information
- 2. Species Status Information
- 3. Species Information
- 4. Threats
- 5. Population and Distribution Objectives
- 6. Broad Strategies and General Approaches to Meet Objectives
- 7. Critical habitat
- 8. Measuring Progress
- 9. Statement on Action Plans
- 10. References
- Appendix A: Standard Breeding Bird Atlas Codes
- Appendix B: Critical Habitat for the Least Bittern in Canada
- Appendix C: Effects on the Environment and Other Species
Recommended citation:
Environment Canada. 2014. Recovery Strategy for the Least Bittern (Ixobrychus exilis) in Canada. Species at Risk Act Recovery Strategy Series. Environment Canada, Ottawa. vi + 41 pp.
For copies of the recovery strategy, or for additional information on species at risk (SAR), including Committee of the Status of Wildlife in Canada (COSEWIC) Status Reports, residence descriptions, action plans and other related recovery documents, please visit the Species at Risk Public Registry.
Cover illustration: © Benoit Jobin, Environment Canada, Canadian Wildlife Service - Quebec Region
Également disponible en français sous le titre :
« Programme de rétablissement du Petit Blongios (Ixobrychus exilis) au Canada »
© Her Majesty the Queen in Right of Canada, represented by the Minister of the Environment, 2014. All rights reserved.
ISBN 978-1-100-19922-1
Catalogue no. En3-4/127-2015E-PDF
Content (excluding the illustrations) may be used without permission, with appropriate credit to the source.
The federal, provincial, and territorial government signatories under the Accord for the Protection of Species at Risk (1996) agreed to establish complementary legislation and programs that provide for effective protection of species at risk throughout Canada. Under the Species at Risk Act (S.C. 2002, c.29) (SARA), the federal competent ministers are responsible for the preparation of recovery strategies for listed Extirpated, Endangered, and Threatened species and are required to report on progress within five years.
The Minister of the Environment and the Minister responsible for the Parks Canada Agency are the competent ministers for the recovery of the Least Bittern, a Threatened species listed in Schedule 1 of SARA, and have prepared this recovery strategy, as per section 37 of SARA. It has been prepared in cooperation with the Provinces of Manitoba, Ontario, Quebec, New Brunswick, and Nova Scotia.
Success in the recovery of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this strategy and will not be achieved by Environment Canada, the Parks Canada Agency, or any other jurisdiction alone. All Canadians are invited to join in supporting and implementing this strategy for the benefit of the Least Bittern and Canadian society as a whole.
This recovery strategy will be followed by one or more action plans that will provide information on recovery measures to be taken by Environment Canada, the Parks Canada Agency, and other jurisdictions and/or organizations involved in the conservation of the species.
Implementation of this strategy is subject to appropriations, priorities, and budgetary constraints of the participating jurisdictions and organizations.
This recovery strategy was prepared by Vincent Carignan and Benoit Jobin ((EC-CWS) - Quebec Region) based on an initial draft by Andrew Horn (Dalhousie University). Earlier drafts were reviewed by members of the National Least Bittern Recovery Team [Vincent Carignan, chair, Ron Bazin (EC-CWS – Prairie & Northern Region), Samara Eaton and Jen Rock (EC-CWS - Atlantic Region), Valerie Blazeski (Parks Canada Agency), Ken DeSmet (Manitoba Conservation), Kari Van Allen and Dave Moore (EC CWS – Ontario Region), Jon McCracken (Bird Studies Canada), and Eva Katic (National Capital Commission)]; and former members of the recovery team [Laurie Maynard and Barbara Slezak (EC-CWS – Ontario Region), Mark McGarrigle (New Brunswick Department of Natural Resources), Todd Norris (Ontario Ministry of Natural Resources), Jennifer Stewart (formerly with EC-CWS – Atlantic Region) and Gershon Rother (formerly with the National Capital Commission)].
Other contributors provided comments on the recovery strategy: Manon Dubé and Ewen Eberhardt (EC-CWS – National Capital Region), Marie-José Ribeyron (formerly with EC-CWS – National Capital Region), Karine Picard, Alain Branchaud and Matthew Wild (EC-CWS – Quebec Region), Diane Amirault-Langlais and Paul Chamberland (formerly with EC-CWS – Atlantic Region), Marie Claude Archambault, Angela Darwin, Angela McConnell, Krista Holmes, Jeff Robinson and Tania Morais (EC-CWS – Ontario Region), David Bland, Michael Patrikeev and Stephen McCanny (Parks Canada Agency), Corina Brydar and Sandy Dobbyn (Ontario Ministry of Natural Resources - Ontario Parks), Jodi Benvenuti, Vivian Brownell, Glenn Desy, Leanne Jennings, Chris Risley, Marie Andrée Carrière, Shaun Thompson, Don Sutherland, Lauren Trute, Doug Tozer and Allen Woodliffe (Ontario Ministry of Natural Resources).
The following individuals provided information on Least Bittern populations and habitat distribution, population trends, life history, survey methods, as well as conservation and management: Nickolas Bartok, Isabelle Beaudoin-Roy, Heidi Bogner, Robert Bowles, Courtney Conway, Glenn Desy, Pierre Fradette, Jonathon French, Christian Friis, Stacey Hay, Gary Huschle, Rudolf Koes, Claudie Latendresse, Soch Lor, Paul Messier, Shawn Meyer, Frank Nelson, Sarah Richer, Dave Roberts, Luc Robillard, Tracy Ruta-Fuchs, François Shaffer, Peter Taylor, Guillaume Tremblay, as well as Breeding Bird Atlas and Marsh Monitoring Program volunteers, and birders in Manitoba, Ontario, Quebec and the Maritimes.
Finally, thanks is given to all other parties including Aboriginal organizations and individuals, landowners, citizens, and stakeholders who provided comments on the present document and/or participated in consultation meetings.
The Least Bittern (Ixobrychus exilis) is North America’s smallest heron. It breeds in freshwater and brackish marshes with tall emergent plants interspersed with open water and occasional clumps of woody vegetation. The species was designated as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 2001 and 2009, and has been listed with the same status under Schedule 1 of the Species at Risk Act (SARA) since 2003.
Around 2-3% of the estimated 43,000 North American pairs are found in Canada, where they are distributed throughout southern Manitoba, Ontario, Quebec, New Brunswick and possibly Nova Scotia. Because of the species' secretive habits and the difficulties of surveying its habitat, population size and trend estimates are imprecise.
Wetland loss and degradation as well as impaired water quality are the primary threats to the Least Bittern throughout its range. Other threats include regulated water levels, invasive species, collisions (with cars and man-made structures), recreational activities, and climate change.
There are unknowns regarding the feasibility of recovery of the Least Bittern. Nevertheless, in keeping with the precautionary principle, a recovery strategy has been prepared as per section 41(1) of SARA as would be done when recovery is determined to be feasible.
The population and distribution objectives for the Least Bittern are to maintain and, where possible, increase the current population size and area of occupancy in Canada. Broad strategies and approaches to achieve these objectives are presented in the Strategic Direction for Recovery section.
Critical habitat is partially identified for the breeding habitat. It corresponds to the suitable habitat within 500 m of records of breeding activity since 2001. A total of 115 critical habitat units are identified, 10 of which are located in Manitoba, 54 in Ontario, 48 in Quebec and 3 in New Brunswick. A schedule of studies outlines key activities to identify additional critical habitat at breeding, foraging, post-breeding dispersal, moulting and migration stopover sites.
One or more action plans will follow this recovery strategy and will be posted on the Species at Risk Public Registry by 2019.
In considering the criteria established by the Government of Canada (2009), unknowns remain as to the recovery feasibility of the Least Bittern. Nevertheless, in keeping with the precautionary principle, this recovery strategy has been prepared as per section 41(1) of SARA as would be done when recovery is determined to be feasible. This recovery strategy addresses the unknowns surrounding the feasibility of recovery.
- Individuals of the wildlife species that are capable of reproduction are available now or in the foreseeable future to sustain the population or improve its abundance.
Yes. Breeding individuals are currently distributed throughout the Canadian range as well as in the United States. - Sufficient suitable habitat is available to support the species or could be made available through habitat management or restoration.
Yes. Sufficient wetland habitat is available to support the species at its current level. Unoccupied and apparently suitable habitat is also available and additional sites could become suitable after restoration efforts or wetland creation. - The primary threats to the species or its habitat (including threats outside Canada) can be avoided or mitigated.
Unknown. The main threats to the species and its breeding habitat as well as methods to avoid or mitigate them are known. However, some of these methods need to be refined and tested in Canada. Furthermore, foraging, post-breeding dispersal, moulting and migration stopover sites have yet to be identified and the threats to those sites will need to be specified. - Recovery techniques exist to achieve the population and distribution objectives or can be expected to be developed within a reasonable timeframe.
Unknown. Habitat stewardship, along with wetland management, restoration and creation techniques have proven to be effective for this species although specific management prescriptions need to be developed. Mitigating other threats, such as off-site effects on wetland habitat quality, however, will be a continuing challenge.
Date of Assessment: April 2009
Common Name (population): Least Bittern
Scientific Name: Ixobrychus exilis
COSEWIC Status: Threatened
Reason for Designation: This diminutive member of the heron family has a preference for nesting near pools of open water in relatively large marshes that are dominated by cattail and other robust emergent plants. Its breeding range extends from southeastern Canada through much of the eastern U.S. Information on the population size and exact distribution of this secretive species is somewhat limited. Nevertheless, the best available evidence indicates that the population is small (about 3000 individuals) and declining (< 30% in the last 10 years), largely owing to the loss and degradation of high-quality marsh habitats across its range.
Canadian Occurrence: Manitoba, Ontario, Quebec, New Brunswick and Nova Scotia
COSEWIC Status History: Designated Special Concern in April 1988. Status re-examined and confirmed in April 1999. Status re-examined and designated Threatened in November 2001 and in April 2009.
1COSEWIC = Committee on the Status of Endangered Wildlife in Canada.
Canada has 2-3% of the Least Bittern reproductive pairs in North America. The species has been listed as Threatened under Schedule 1 of the Species at Risk Act (SARA) (S.C. 2002, c. 29) since 2003. In Quebec, it has been listed as Vulnerable under the Act respecting threatened or vulnerable species (R.S.Q., c. E-12.01) since 2009. In Ontario, it has been listed as Threatened on the Species at risk in Ontario list since 2004 and regulated under the Endangered Species Act, 2007 (S.O. 2007, C. 6) since 2008. As of August 2013, the species had not been listed in Manitoba, New Brunswick or Nova Scotia.
The International Union for the Conservation of Nature ranks the global population of the Least Bittern as “Least Concern” (BirdLife International, 2009). NatureServe (2010) conservation ranks for Canada and the United States vary widely as shown in Table 1.
Global Rank (G) | National Rank (N) | Sub-national Rank (S) |
---|---|---|
1 1 - Critically Imperiled; 2 - Imperiled; 3 - Vulnerable; 4 - Apparently Secure; 5 – Secure; H – possibly extirpated; NR – Not Ranked 2 In most states along the Gulf coast (e.g., Texas, Louisiana, Florida), where it is resident year-round, the species is not listed, and has been recently removed from the federal list of "Species of Management Concern" (USFWS, 2002). |
||
G5 (Secure) |
N4B - Canada (Apparently Secure) N5B, N5N - United States (Secure) |
Manitoba (S2S3B) ; Ontario (S4B) ; Quebec (S2S3B); New Brunswick (S1S2B) ; Nova Scotia (SNRB) SH (Utah) ; S1 (California, Delaware, District of Columbia, Kentucky, Massachusetts, New Hampshire, Oregon, Pennsylvania, West Virginia) ; S2 (Arkansas, Colorado, Connecticut, Illinois, Kansas, Maine, Maryland, Michigan, Nevada, Ohio, Rhode Island, South Dakota, Tennessee, Vermont) ; S3 (Arizona, Indiana, Iowa, Mississippi, Missouri, New Jersey, New Mexico, New York, North Carolina, Virginia, Wisconsin) |
Measuring about 30 cm and weighing 80 g, the Least Bittern is North America’s smallest heron (Kushlan and Hancock, 2005). It is brown and buffy overall, with broad buff streaks on its white underside, and a contrasting back and crown that is glossy black in adult males but lighter in females and juveniles. Buff wing patches, which are especially obvious when the bird flushes, distinguish this species from all other marsh birds. When disturbed, the bird uses a rail-like “rick-rick-rick-rick”, otherwise its call consists of a repeated “coo-coo-coo” (Sibley, 2000). Further details are provided in the COSEWIC (2009) status report.
Global population and distribution
During the nesting season, the Least Bittern can be found from southern Canada to South America, including the Caribbean. There are year-round resident populations in river valleys and coastal areas farther south to northern Argentina and southern Brazil (COSEWIC, 2009; Poole et al., 2009). Isolated migrant populations also breed in Oregon, California, and New Mexico (Figure 1). There are an estimated 43,000 pairs of Least Bitterns in North America (Delany and Scott, 2006).
The migratory routes of the Least Bittern are unknown, but it is presumed that they migrate in a broad front that is locally funneled by north-south oriented peninsulas and coasts such as found in the closely related Little Bittern (Ixobrychus minutus) of Eurasia (Nankinov, 1999). The distribution of the adults during the moulting phase needs further study but the timing of this phase (mid-September to mid-December) suggests it mostly takes place during migration (Poole et al., 2009).
Least Bitterns winter from California to Florida south to Mexico and Latin America. The winter habitat is poorly known, although the species is presumed to occupy brackish and saline swamps and marshes (Poole et al., 2009).
Canadian population and distribution
In Canada, the Least Bittern generally breeds south of the Canadian Shield in Manitoba, Ontario, Quebec, New Brunswick and possibly Nova Scotia (COSEWIC, 2009; Figure 2). The species has been reported as a vagrant in other provinces. The Canadian breeding population is estimated at 1,500 pairs (between 1000 and 2800; COSEWIC, 2009; Table 2).
Province | No. of breeding pairs (estimated) (COSEWIC, 2009) |
No. of atlas blocks (100 km2) in which the species was detected |
---|---|---|
Manitoba | ~ 200 | Unavailable |
Ontario | >500 | 210 (during the 2001-2005 period, 2nd atlas); Cadman et al. (2007) |
Quebec | 200-300 | 38 (during the 2010-2012 period, 2nd atlas); Atlas des oiseaux nicheurs du Quebec (2012) |
New Brunswick | unknown | 7 (during the 2005-2010 period, 2nd atlas); Bird Studies Canada (2009, 2010) |
Nova Scotia | unknown | 0 (during the 2005-2010 period, 2nd atlas); Bird Studies Canada (2009, 2010) |
Despite recent advances in methods to detect the species (Conway, 2009; Johnson et al. 2009, Jobin et al. 2013) which have led to increases in reported numbers of breeding individuals, there is a general consensus that the species has declined (Sandilands and Campbell, 1988; Austen et al., 1994; James, 1999; Environment Canada, 2007; Poole et al., 2009). In Canada, this tendency has been observed in the core of the species’ range with an average annual decline of 10.6% (95% CI = -6.9% to -14.3%) in the Great Lakes Basin from 1995 to 2007 (Archer and Jones, 2009). An analysis of the data from the Ontario breeding bird atlases yielded a similar trend (-10%/year, 95% CI = 5% to -16%, 1995-2006; Cadman et al., 2007). Conversely, in the Lake Simcoe-Rideau region (Ontario), there were no significant changes in the probability of observation (Cadman et al., 2007).
Current understanding of the ecological needs of the Least Bittern may be biased because selection of study sites and associated findings may be influenced by how easily the sites can be accessed and surveyed. Furthermore, the species' apparent habitat needs might be distorted by limitations in what habitat is available now compared to historically.
Breeding period
In Canada, breeding habitats are occupied from early May to early September (Fragnier, 1995). They consist of freshwater and brackish marshes with dense, tall, robust emergent plants (mainly cattail Typha spp), interspersed with relatively shallow (10-50 cm) open water and occasional clumps of shrubby vegetation (Parsons, 2002; Hay, 2006; Budd, 2007; Jobin et al., 2007; Yocum, 2007; Griffin et al., 2009). Rehm and Baldassarre (2007) refer to these conditions as hemi-marsh.
Water levels approximating those of a natural regime are an important breeding habitat feature as high water levels can flood nests that are constructed just above the water, whereas low levels reduce food availability and facilitate predators' access to nests (Arnold, 2005).
Densities of Least Bitterns appear to be mostly affected by local conditions such as water depth, food abundance, vegetation type and cover availability rather than marsh area or marsh area within the surrounding landscape (Arnold, 2005; Tozer et al. 2010). Indeed, although Least Bitterns usually nest in larger marshes (> 5 ha), territorial individuals have been found in marshes as small as 0.4 ha (Gibbs and Melvin, 1990). The species can also be semi-colonial, particularly in highly productive habitats (Kushlan, 1973; Bogner, 2001; Meyer and Friis, 2008), where they can reach a density of up to five calling birds or nests per hectare (Arnold, 2005; Poole et al., 2009). Although typically territorial, no definitive information exists on territory size and home range for the Least Bittern. Bogner and Baldassarre (2002a) found that breeding individuals moved an average maximum distance of 393 m ± 36 SE between two points while Griffin et al. (2009) found an average maximum distance of more than 2,000 m for breeding individuals in Missouri.
The Least Bittern is a visual predator that forages for prey (e.g., small fish, tadpoles, molluscs, insects) in clear, shallow water near openings in the marsh vegetation, often from platforms it constructs by bending emergent vegetation (Poole et al., 2009). This foraging method probably explains why they prefer marshes interlaced with channels, such as those created by muskrats (Poole et al., 2009).
Non-Breeding period
There is little information on ecological needs of Least Bitterns and habitat characteristics in moulting, post-breeding dispersal, migration and wintering sites, although it is presumed that they are similar to those of breeding habitats.
Threat | Level of Concern 1 | Extent | Occurrence | Frequency | Severity 2 | Causal Certainty 3 | |
---|---|---|---|---|---|---|---|
1 Level of Concern: signifies that managing the threat is of (high, medium or low) concern for the recovery of the species, consistent with the population and distribution objectives. This criterion considers the assessment of all the information in the table. 2 Severity: reflects the population-level effect (High: very large population-level effect, Moderate, Low, Unknown). 3 Causal certainty: reflects the degree of evidence that is known for the threat (High: available evidence strongly links the threat to stresses on population viability; Medium: there is a correlation between the threat and population viability e.g. expert opinion; Low: the threat is assumed or plausible). 4 Each threat is evaluated at the local level (each site) and at the rangewide level. When two items are present in a box, this means that the threat level is not the same for both scales (Local scale / Rangewide scale). |
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Habitat Loss or Degradation | Wetland destruction and degradation | High | Widespread | Current | Recurrent | High | High |
Habitat Loss or Degradation | Impaired water quality | Medium-High | Widespread | Current | Continuous/Recurrent 4 | Moderate | Medium |
Habitat Loss or Degradation | Regulated water levels | Medium | Local | Current/Unknown | Recurrent/Unknown | High/Low | Medium |
Exotic, Invasive or Introduced Species or Genome | Invasive species | Medium | Local | Current | Continuous | High/Moderate | Medium |
Accidental Mortality | Collisions with cars and man-made structures | Low | Local | Current | Unknown | Unknown | Unknown |
Disturbance or Harm | Recreational activities | Low | Local | Current | Recurrent | Moderate | Medium |
Climate and Natural Disasters | Climate change | Low | Widespread | Anticipated | Unknown | Moderate/Unknown | Medium/Low |
Natural Processes or Activities | Diseases | Low | Widespread | Current | Unknown | High/Low | Low |
Threats are listed in order of decreasing level of concern. However, apart from wetland destruction and degradation and impaired water quality, the level of concern is speculative because the prevalence and impact of threats are poorly documented in Canada. Some threats that occur on wintering grounds and along migration routes may have consequences on Least Bitterns that migrate to Canada for breeding. The absence of muskrats (who open corridors in the marsh vegetation) and the reduction of natural disturbances (e.g., fires that prevent shrubs from invading the habitat) are also limiting factors for the species.
Loss of wetland habitat as a result of human activities is thought to have severely reduced Least Bittern numbers across North America. The rate of large-scale wetland loss in southern Canada appears to have slowed in recent years, but wetlands continue to be drained for housing development and/or conversion to agricultural uses (Ducks Unlimited Canada, 2010). In Quebec, 80% of wetlands along the St. Lawrence River have been lost since European settlement (James, 1999; Painchaud and Villeneuve, 2003). Development up to the edge of marshes as well as fragmentation facilitates access to deeper portions of marshes by some mammalian predators [1], particularly raccoons (Jobin and Picman, 1997). Loss and degradation of wetlands is also an important factor in the United States (Dahl, 2006), affecting the migration and wintering habitats of the Canadian breeding population.
Run-off, siltation, acid rain and eutrophication can reduce prey abundance (Weller, 1999) and increase the likelihood of disease and toxicity. Any reduction in water clarity will also likely reduce the foraging success of a visual feeder such as the Least Bittern.
Single source pollution events such as toxic spills are particularly likely in marshes that border the busy shipping lanes of the St. Lawrence River and Great Lakes (Chapdelaine and Rail, 2004). The effects of such events on Least Bitterns have not been investigated but could be important since the species is known to bio-accumulate toxins in its eggs and feathers (Causey and Graves, 1969).
Since water-level management along the St. Lawrence River and Lake Ontario was established in the 1950s, the average maximum flow has decreased in summer and the average minimum flow has increased in winter (Morin and Leclerc, 1998). However, deviations from the regulation plan occur regularly and can impact the Least Bittern during crucial periods of reproduction (DesGranges et al., 2006). This situation may also be taking place in other important waterways such as the Ottawa River and even inland. Although Least Bitterns mostly occupy sites where water levels are stable during the breeding season, any dramatic change in water levels during this period is liable to affect the species negatively.
Prolonged periods of high water levels can reduce the extent of cattail marshes, both directly through flooding and indirectly by making conditions more favorable for other species such as Wild Rice (Zizania palustris) that are less suitable for nesting Least Bitterns (Sandilands and Campbell, 1988; Timmermans et al., 2008). Conversely, prolonged periods of relatively stable water levels may increase the density of cattail stands and eliminate open pools required by the species. Jobin et al. (2009) showed that the abundance of a Least Bittern population was reduced rapidly following a pronounced decrease of water depth due to a breach in an impounded wetland during the reproductive season followed by a rapid increase in abundance the following year when water depth returned to previous levels.
Several species of invasive plants and animals are increasing in range and abundance in North American marshes, largely due to human interventions. Purple Loosestrife (Lythrum salicaria), Reed Canary Grass (Phalaris arundinacea), European Common Reed (Phragmites autralis spp. australis), Flowering Rush (Butomus umbellatus) as well as a hybrid cattail (Typha x glauca) in the Great Lakes region are crowding out native emergent plants (Lavoie et al., 2003; Hudon, 2004; Jobin, 2006; Jobin et al., 2007; Latendresse and Jobin, 2007; Wilcox et al., 2007). While the Least Bittern can breed in a variety of emergent plants, including stands of invasive species, they preferentially breed in cattails (Poole et al., 2009). Floating invasive plants (e.g., European Frog bit [Hydrocharis morsus-ranae] and Water Chestnut [Trapa natans]), can also alter habitat structure namely by accelerating marsh succession to drier conditions that are suboptimal for feeding and breeding (Blossey et al., 2001).
Populations of invasive animals such as Common Carp (Cyprinus carpio) are increasing in wetlands occupied by the Least Bittern, especially in southern Ontario and Quebec. In addition to their deleterious effects on ecosystem function, they may impact the Least Bittern more directly when stirring up sediments as they forage thereby reducing water clarity (Wires et al., 2010).
Least Bitterns fly at low levels and migrate at night, two characteristics which make them susceptible to collisions with vehicles, buildings, guy wires, power lines, barbed wire fences, and towers. These collisions may be frequent enough at some sites to threaten local populations (Poole et al., 2009). In one case, 12 Least Bitterns were killed in collisions with vehicles and four died after being impaled on a fence during one weekend on a road that passes through a refuge in Louisiana (Guillory, 1973). Least Bitterns have also been found dead along the Long Point (Ontario) causeway on a few occasions (Ashley and Robinson, 1996; J. McCracken personal communication). These incidents suggest that roads or structures built adjacent to suitable wetlands can cause mortality for birds moving between habitat patches or during migration.
Although the Least Bittern can tolerate a certain level of human activity near wetlands used for breeding, including the occasional passage of small boats near their foraging areas (Poole et al., 2009), they seem to prefer nesting outside high density urban areas (Smith-Cartwright and Chow-Fraser, unpublished results). However, infrequent and unpredictable disturbance may be as disruptive to the Least Bittern as it is for other species that are intolerant of human activity (Nisbet, 2000). Frequent use of call broadcasts by recreational birders in wetlands where birding pressure is intense may also be disruptive to breeding Least Bitterns although the importance of this threat has not been evaluated. Finally, direct impacts such as waves from motorized watercrafts can erode wetland edges and possibly flood or upset nests.
Climate change has the potential of having unpredictable, widespread and severe effects on the Least Bittern and its habitat. Climate change could increase the frequency of events such as floods and storms that can destroy nests and habitat, and may also change the overall hydrological and temperature regimes that account for the Least Bitterns’ distribution in Canada. For example, the reduction of water levels caused by elevated temperatures will likely reduce the area of wetlands, and lead to reduced prey abundance (Mortsch et al., 2007; Wires et al., 2010). Alternatively, a potential northward expansion by the species could favor the use of numerous wetlands in the boreal forest although the quality of these habitats for breeding purposes would have to be assessed.
The impact of various diseases and parasitism have been poorly studied in Least Bittern populations. Presumably, individuals are susceptible to diseases known to affect other wading birds ((Friend and Franson, 1999; Wires et al., 2010). The Least Bittern is also one of 326 bird species in which West Nile Virus has been found (Center for Disease Control, 2009).
The population and distribution objectives for the Least Bittern are to maintain and, where possible, increase the current population size and area of occupancy in Canada. These objectives are considered possible in many parts of the range where adequate, yet currently unoccupied, breeding, foraging, post-breeding dispersal, moulting and migration stopover habitat is available or could be restored. Part of these objectives can only be achieved over the long term (>10 years).
The species' historical abundance and distribution are not well known, and specific habitat needs for different life stages and locations across its Canadian range are not understood well enough at present to set quantitative objectives. This may become possible in subsequent iterations of this recovery strategy as knowledge gaps are filled.
The following activities have been undertaken or completed in Canada since 2000:
- Literature reviews of all available information on the Least Bittern (McConnell, 2004; Gray Owl Environmental Inc., 2009);
- National Least Bittern survey protocol for the breeding season (Jobin et al., 2011 a,b);
- National protocol for capturing, banding, radio-tagging and tissue sampling Least Bitterns in Canada (MacKenzie and McCracken, 2011);
- Surveys of potential and historical sites have been conducted in southern Manitoba (2003-2008; R. Bazin pers. comm.; Hay, 2006), in Ontario (2001-2012; Bowles, 2002; Desy, 2007; Meyer and Friis, 2008) and in Quebec (2004-2013; Jobin, 2006; Jobin et al., 2007; Latendresse and Jobin, 2007; Jobin and Giguère, 2009);
- Directed surveys in National Wildlife Areas in Ontario and Quebec;
- Masters and PhD theses completed on Least Bittern breeding habitat in Ontario (N. Bartok University of Western Ontario; P. Quesnelle - Carleton University; D. Tozer – Trent University) and Manitoba (S. Hay - University of Manitoba);
- On-going monitoring programs: Great Lakes Coastal Wetland Monitoring Program (Canadian Wildlife Service-Ontario Region; Meyer et al., 2006); Marsh Monitoring Program in Ontario since 1994 and in Quebec since 2004; Monitoring of Least Bittern presence in several wetlands in southern Quebec as part of the avian species at risk annual breeding sites monitoring (SOS-POP); Prairies and Parkland pilot Marsh Monitoring Program since 2008;
- Creation of the Samuel-de-Champlain biodiversity reserve (Natural heritage conservation Act of Quebec; R.S.Q. c. C-61.01) which will preserve 487 ha of wetlands on the shores of the Richelieu River near the Quebec/USA border. This will include two of the Least Bittern critical habitat units (Baie McGillivray and Rivière Richelieu-Frontière);
- Broad efforts to protect, manage, and restore wetlands in Ontario are ongoing, for example, through the Eastern Habitat Joint Venture of the North American Waterfowl Management Plan and the Great Lakes Sustainability Fund;
- The Walpole Island First Nation is developing an ecosystem protection plan based on the community’s traditional ecological knowledge.
Threats or Limiting Factor | Broad Strategy to Recovery | Priority | General Description of Research and Management Approaches |
---|---|---|---|
All | Stewardship and management of the species and its suitable habitat | High |
|
Knowledge gaps | Surveys and monitoring | High |
|
Wetland destruction; Impaired water quality; Regulated water levels; Knowledge gaps |
Research | High |
|
All | Communication and Partnerships | Medium |
|
Critical habitat is partially identified for the Least Bittern in this recovery strategy. As there is limited information concerning most foraging, moulting, post-breeding dispersal and migration stopover habitats, critical habitat is only identified for the breeding habitat. A schedule of studies (section 7.2) is proposed to complete the identification of critical habitat.
The identification of critical habitat is based on two aspects: habitat suitability and habitat occupancy.
Habitat suitability refers to the attributes of habitats in which individuals may carry out breeding activities (e.g., courtship, territory defense, nesting). The biophysical attributes of suitable Least Bittern breeding habitat include:
- permanent wetlands [2] (marshes and shrubby swamps within the boundaries of the high-water mark), AND
- tall and robust emergent herbaceous and/or woody vegetation interspersed with areas of open water (hemi-marsh conditions), AND
- Water level fluctuations close to those of a natural regime
Based on knowledge related to the average maximum movements during the breeding season (~400 m according to Bogner and Baldassarre, 2002b; 2,000 m according to Griffin et al., 2009), the suitable habitat within a 500 m radius was selected as representative of the area used by a Least Bittern individual or pair.
Habitat occupancy relates to areas of suitable habitat that have documented use for breeding purposes in one or multiple years. Confirmed breeding records (see Appendix A for definitions) constitute the highest indication of habitat occupancy and therefore of the presence of suitable habitat. However, since confirming breeding is difficult for this secretive species (Tozer et al., 2007), records of multiple probable breeders in a single year or probable breeders in multiple years can also be used as indicators of habitat suitability, in particular as a demonstration of fidelity to specific wetlands. The remaining records of breeding activities (e.g., possible breeders) were not considered as sufficient indicators of the suitability of the habitat for reproduction since the Least Bittern may use some wetlands sporadically (e.g., for movements) or for non-reproductive purposes.
Given that wetland habitats are dynamic throughout the Canadian range, recent information may be more reliable for evaluating suitable habitat and Least Bittern occupancy. In light of this, the selection of records dating back a maximum of 10 years from when the recovery strategy was being prepared (i.e. starting in 2001) has been identified as appropriate. Furthermore, 2001 was the first year of data collection for the second Ontario Breeding Bird Atlas, which enabled confirmation of the continued use of individual wetlands (fidelity) at the heart of the species’ range in Canada. Records older than 2001 will need to be validated to determine the continued presence of suitable habitat and current occupancy by the Least Bittern (see section 7.2).
Critical habitat is identified in this recovery strategy as the suitable habitat within 500 m of coordinates corresponding to the following minimum breeding activity:
- one record of confirmed breeding since 2001; OR
- two records of probable breeding in any single year since 2001; OR
- one record of probable breeding in each of two separate years within a 5-year floating window [3] since 2001
Depending on its area, structure and the nature of observed reproductive activities, a wetland can be identified as a single critical habitat unit or can include multiple units. Overlapping units are merged together to form a single larger unit.
Using these criteria, 115 critical habitat units containing up to 17 102 ha of Least Bittern critical habitat have been identified (see Appendix B), including 10 in Manitoba (1,856 ha), 54 in Ontario (10,740 ha), 48 in Quebec (4,615 ha) and 3 in New Brunswick (137 ha). Within a critical habitat unit, any man-made structure (e.g., roads, wharves, powerline poles) or areas (e.g., ploughed agricultural land, deep open water) that do not possess the biophysical attributes of suitable habitat are not identified as critical habitat.
The Least Bittern may occasionally nest in non-traditional habitats (e.g., roadside ditches, sewage lagoons) that are anthropogenic in nature and not managed for conservation purposes. These habitats do not provide sustained, high quality breeding conditions given that they may be the object of frequent interventions that could negatively affect breeding individuals. Consequently, they are not identified as critical habitat under SARA, even if breeding is confirmed. However, the general prohibitions under SARA and the Migratory Birds Convention Act, 1994 (S.C., 1994, c. 22) protecting the birds and their residences (nests) from damage or destruction remain in effect.
Description of Activity | Rationale | Timeline |
---|---|---|
a The 1991 year has been selected based on the fact that Conservation Data Centres consider records older than 20 years to be historical. | ||
Conduct surveys in wetlands where:
|
Additional critical habitat units identified, particularly in more remote areas | 2014-2019 |
Characterize foraging, post-breeding dispersal, moulting and migration stopover habitats in Canada and survey Least Bitterns within them in the appropriate periods of the year | Additional critical habitat units identified; Needed to conserve the species in throughout its life cycle in Canada | 2014-2019 |
Destruction is determined on a case by case basis. Destruction would result if part of the critical habitat was degraded, either permanently or temporarily, such that it would not serve its function when needed by the species (Government of Canada, 2009). Destruction may result from a single activity or multiple activities at one point in time or from the cumulative effects of one or more activities over time. Examples of activities likely to result in the destruction of critical habitat for the Least Bittern are shown in Table 6.
Description of the Activity* | Description of the Effect (biophysical attributes or other) |
Scale of Activity Likely to Destroy Critical Habitat** Site |
Scale of Activity Likely to Destroy Critical Habitat** Area |
Scale of Activity Likely to Destroy Critical Habitat** Landscape |
Timing Considerations |
---|---|---|---|---|---|
a Activities required to manage, inspect and maintain existing infrastructures that are not critical habitat but whose footprints may be within or adjacent to critical habitat units are not examples of activities likely to result in the destruction of critical habitat provided that they are carried out in a manner consistent with Least Bittern critical habitat conservation. Furthermore, management of wetlands for wildlife conservation purposes does not typically result in destruction of critical habitat if activities take place when the individuals are not present in the habitat (after migration). For additional information, communicate with Environment Canada – Canadian Wildlife Service at : enviroinfo@ec.gc.ca. b Site : anticipated effect close to 1 x 1 km; Area : 10 x 10 km; Landscape : 100 x 100 km |
|||||
Infilling, excavation or draining of wetlands (e.g., infrastructure development and construction, superficial mineral extraction; underground mineral/hydrocarbon extraction, dredging and channelization) |
|
X | X | Applicable at all times | |
Activities that generate soil run-off and increased water turbidity or nutrient influx (e.g., cultivating the land next to a wetland without proper vegetation buffers) |
|
X | X | Applicable at all times | |
Introduction of invasive vegetation, fish and invertebrate species |
|
X | X | Applicable at all times | |
Repeated use of vehicles and motor boats within or close to wetlands |
|
X | Applicable at all times in relation to erosion; Applicable during the breeding period in relation to the flooding of nest component | ||
Prescribed burns or other means of natural vegetation removal within wetland habitats |
|
X | Can be conducted when individuals have left the habitat (after the fall migration) | ||
Deposition of deleterious substances (including snow), either directly (in water) or indirectly (upstream, soil) |
|
X | X | Applicable at all times | |
Construction of infrastructures (e.g., roads, houses, boat ramps) which increase the access to critical habitat |
|
X | X | Applicable at all times | |
Presence of livestock that removes or tramples the vegetation |
|
X | Applicable at all times |
The performance indicators presented below provide a way to define and measure progress toward achieving the population and distribution objectives.
- the population size of Least Bittern is maintained and, where possible, increased;
- the area of occupancy is maintained and, where possible, increased.
One or more action plans associated with the recovery strategy will be elaborated in the coming years. They will be posted on the Species at Risk Public Registry by 2019.
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Atlas code* | Description | |
---|---|---|
* Atlas codes and descriptions can vary slightly from one province to another but convey similar meanings. Atlas codes for possible breeding are not presented here. | ||
Probable breeding |
P
|
Pair observed in their breeding season in suitable nesting habitat. |
Probable breeding |
T
|
Permanent territory presumed through registration of territorial behaviour (song, etc.), or the occurrence of an adult bird, on at least two days, a week or more apart, at the same place, in suitable nesting habitat during the breeding season. |
Probable breeding |
D
|
Courtship or display between a male and a female or two males including courtship, feeding or copulation. |
Probable breeding |
V
|
Visiting probable nest site. |
Probable breeding |
A
|
Agitated behaviour or anxiety calls of an adult indicating nest-site or young in the vicinity. |
Probable breeding |
B
|
Brood patch on adult female or cloacal protuberance on adult male. |
Confirmed breeding |
NB
|
Nest building or carrying nest materials. |
Confirmed breeding |
DD
|
Distraction display or injury feigning. |
Confirmed breeding |
NU
|
Used nest or egg shells found (occupied or laid within the period of the survey). Use only for unique and unmistakable nests or shells. |
Confirmed breeding |
FY
|
Recently fledged young or downy young. |
Confirmed breeding |
AE
|
Adults leaving or entering nest sites in circumstances indicating occupied nest (including nests which content cannot be seen). |
Confirmed breeding |
FS
|
Adult carrying fecal sac. |
Confirmed breeding |
CF
|
Adult carrying food for young during its breeding season. |
Confirmed breeding |
NE
|
Nest containing eggs. |
Confirmed breeding |
NY
|
Nest containing young seen or heard. |
Name of the Critical Habitat Unit |
10 x 10 km UTM Grid ID 1 | UTM Grid Coordinates 2 Easting |
UTM Grid Coordinates 2 Northing |
Quarter Sections 3 Containing Critical Habitat |
Quarter Sections 3 Containing Critical Habitat |
Critical Habitat Unit Area (ha) 4 | Description | Land Tenure 5 |
---|---|---|---|---|---|---|---|---|
|
||||||||
Brokenhead Swamp | 14PA82 | 680000 | 5520000 | NE-12-10-08-E1 NW-07-10-09-E1 NW-18-10-09-E1 |
SW-18-10-09-E1 SE-13-10-08-E1 NE-13-10-08-E1 |
111 | Located in a freshwater wetland east of PR302, north of Hwy 1 and south of Hwy 15 near the town of Ross | Non federal |
Buffalo Lake | 14NB92 | 590000 | 5620000 | NW-10-21-02-W1 NE-10-21-02-W1 SE-15-21-02-W1 NE-15-21-02-W1 |
SW-15-21-02-W1 NW-14-21-02-W1 SW-14-21-02-W1 NW-11-21-02-W1 |
241 | Located in a freshwater wetland north of PR419, east of PR512 and north of Hwy 17 near the town of Chatfield | Non federal |
Fish Lake | 14PB12 | 610000 | 5620000 | SW-30-20-02-E1 NW-30-20-02-E1 |
SE-25-20-01-E1 NE-25-20-01-E1 |
131 | Located in a freshwater wetland east of Hwy 17 and west of Hwy 7 near the town of Meleb Non federal | Non federal |
Little Birch Lake West | 14NB66 | 560000 | 5660000 | SW-11-25-05-W1 SE-11-25-05-W1 NW-11-25-05-W1 |
NE-11-25-05-W1 SE-14-25-05-W1 SW-14-25-05-W1 |
104 | Located in a freshwater wetland south of PR325 and north of Sleeve Lake near the town of Ashern | Non federal |
Little Birch Lake East | 14NB66 | 560000 | 5660000 | SE-12-25-05-W1 SW-12-25-05-W1 |
NE-01-25-05-W1 NW-01-25-05-W1 |
79 | Located in a freshwater wetland south of PR325 and north of Sleeve Lake near the town of Ashern | Non federal |
Rat River Swamp West | 14PV65 | 660000 | 5450000 | NW-20-03-06-E1 SE-29-03-06-E1 NE-29-03-06-E1 NE-20-03-06-E1 SE-21-03-06-E1 SW-20-03-06-E1 NW-16-03-06-E1 SE-20-03-06-E1 NE-21-03-06-E1 NW-21-03-06-E1 |
NE-17-03-06-E1 NW-17-03-06-E1 SW-27-03-06-E1 SE-19-03-06-E1 NW-27-03-06-E1 SW-28-03-06-E1 NW-28-03-06-E1 SE-28-03-06-E1 NE-28-03-06-E1 NE-18-03-06-E1 |
693 | Located in a freshwater wetland east of Hwy 59, west of PR302 and north of the Vita Drain along the Rat River near the towns of Rosa and Zhoda | Non federal |
Rat River Swamp Centre | 14PV65 | 660000 | 5450000 | NW-26-03-06-E1 NE-27-03-06-E1 NE-34-03-06-E1 |
SE-34-03-06-E1 NW-35-03-06-E1 SW-35-03-06-E1 |
125 | Located in a freshwater wetland east of Hwy 59, west of PR302 and north of the Vita Drain along the Rat River near the towns of Rosa and Zhoda | Non federal |
Rat River Swamp East | 14PV75 14PV76 |
670000 670000 |
5450000 5460000 |
NW-34-03-07-E1 NE-33-03-07-E1 NW-33-03-07-E1 |
SW-04-04-07-E1 SE-04-04-07-E1 SW-03-04-07-E1 |
190 | Located in a freshwater wetland east of Hwy 59, west of PR302 and north of the Vita Drain along the Rat River near the towns of Rosa and Zhoda | Non federal |
Sleeve Lake | 14NB66 | 560000 | 5660000 | NW-19-24-04-W1 NE-19-24-04-W1 |
SE-30-24-04-W1 SW-30-24-04-W1 |
79 | Located in a freshwater wetland south of PR325 and south of Little Birch Lake near the town of Ashern | Non federal |
Unnamed Lake (locally called Little Sleeve Lake) | 14NB66 | 560000 | 5660000 | NE-36-24-05-W1 SE-01-25-05-W1 SE-06-25-04-W1 |
NW-31-24-04-W1 SW-06-25-04-W1 |
103 | Located in a freshwater wetland south of PR325 between Little Birch Lake and Sleeve Lake near the town of Ashern | Non federal |
Total 1,856 in 10 critical habitat units |
Name of the Critical Habitat Unit |
10 x 10 km UTM Grid ID 1 | UTM Grid Coordinates 2 Easting |
UTM Grid Coordinates 2 Northing |
Critical Habitat Unit Area (ha) 3 | Description | Land Tenure 3 |
---|---|---|---|---|---|---|
|
||||||
Rainy Lake | 15VP99 | 490000 | 5390000 | 104 | Rainy Lake, District of Rainy River | Non federal |
Lighthouse Point Provincial Nature Reserve | 17LG63 | 360000 | 4630000 | 84 | Lighthouse Point Provincial Park, Essex County | Non federal |
Hillman Marsh Conservation Area | 17LG75 | 370000 | 4650000 | 154 | Hillman Marsh Conservation Area, Essex County | Non federal |
Wheatley East Two Creeks | 17LG85 17LG86 |
380000 380000 |
4650000 4660000 |
84 | Wheatley Provincial Park, Municipality of Chatham-Kent | Non federal |
St. Clair NWA Marsh Complex - St. Clair Unit | 17LG89 | 380000 | 4690000 | 712 | St. Clair NWA - St. Clair Unit, Municipality of Chatham-Kent | Federal and Non federal |
St. Clair Marsh Complex | 17LH80 | 380000 | 4700000 | 155 | Middle section St. Clair Marsh, Municipality of Chatham-Kent | Non federal |
Mitchell's Bay, Lake St. Clair | 17LH80 | 380000 | 4700000 | 141 | Mitchell's Bay, Lake St. Clair, Municipality of Chatham-Kent | Non federal |
St. Clair NWA Marsh Complex - Bear Creek Unit | 17LH80 17LH81 |
380000 380000 |
4700000 4710000 |
300 | St. Clair NWA - Bear Creek Unit, Municipality of Chatham-Kent | Federal and Non federal |
Rondeau Provincial Park 1 | 17MG28 | 420000 | 4680000 | 165 | West side of Rondeau Provincial Park, Municipality of Chatham-Kent | Non federal |
Rondeau Provincial Park 2 | 17MG28 17MG38 |
420000 430000 |
4680000 4680000 |
83 | Rondeau Provincial Park, Municipality of Chatham-Kent | Non federal |
Hullett Marsh Complex | 17MJ63 | 460000 | 4830000 | 82 | East of Clinton, Huron County | Non federal |
Rankin River Wetland | 17MK76 17MK86 |
470000 480000 |
4960000 4960000 |
92 | South of Sky Lake Management Area, Bruce County | Non federal |
Big Creek NWA, Crown Marsh, Long Point Provincial Park | 17NH41 17NH51 |
540000 550000 |
4710000 4710000 |
1281 | West end of Long Point Sandspit, Norfolk County | Federal and Non federal |
Unnamed Wetland - Haldimand-Norfolk County | 17NH41 | 540000 | 4710000 | 83 | Wetland east of Long Point Road, Norfolk County and portion of wetland in Big Creek NWA -Big Creek Unit | Federal and Non federal |
Little Rice Bay Marsh - Thoroughfare Unit, Long Point NWA | 17NH51 | 550000 | 4710000 | 141 | Little Rice Bay Marsh area of Thoroughfare Unit, Norfolk County | Federal and Non federal |
Big Rice Bay Marsh - Thoroughfare Unit, Long Point NWA | 17NH51 | 550000 | 4710000 | 418 | Big Rice Bay Marsh area of Thoroughfare Unit, Norfolk County | Federal and Non federal |
Long Point Provincial Park | 17NH51 | 550000 | 4710000 | 119 | Wetland in Long Point Provincial Park, Norfolk County with portion extending into Long Point NWA-Thoroughfare Unit | Federal and Non federal |
Indian Creek Wetland | 17NH52 | 550000 | 4720000 | 1234 | West of Turkey Point, Norfolk County | Non federal |
Long Point Unit - Long Point NWA | 17NH61 17NH71 |
560000 570000 |
4710000 4710000 |
1068 | Along north shoreline of Long Point Unit, Norfolk County | Federal |
Luther Marsh | 17NJ46 | 540000 | 4860000 | 82 | East part of Luther Marsh Conservation Area, Wellington County | Non federal |
Arkell - Corwhin Wetland Complex | 17NJ62 17NJ72 |
560000 570000 |
4820000 4820000 |
82 | South of Eden Mills, Regional Municipality of Halton | Non federal |
Tiny Marsh (Ti7) | 17NK83 | 580000 | 4930000 | 310 | Northeast of Allenwood, Simcoe County | Non federal |
Wye Marsh (TA2) | 17NK84 17NK85 17NK95 |
580000 580000 590000 |
4940000 4950000 4950000 |
323 | Southwest section of Wye Marsh, Simcoe County | Non federal |
Sturgeon Bay Marsh | 17NK95 17PK05 |
590000 600000 |
4950000 4950000 |
104 | Southwest end of the Trent Severn Waterway, Simcoe County | Federal and Non federal |
Cache Bay Wetland | 17NM73 | 570000 | 5130000 | 123 | Cache Bay Wetland, District Municipality of Nipissing | Non federal |
Beaverton River Wetland Complex | 17PJ59 | 650000 | 4890000 | 82 | Beaverton River Wetland Complex, Regional Municipality of Durham | Non federal |
Matchedash Bay Wetland (SE11) | 17PK05 | 600000 | 4950000 | 115 | North end of Matchedash Bay Wetland, Simcoe County | Non federal |
Wenona Marsh | 17PK26 | 620000 | 4960000 | 81 | South of Gravenhurst, District Municipality of Muskoka | Non federal |
Sturgeon Lake No. 26 | 17PK71 17PK72 |
670000 670000 |
4910000 4920000 |
190 | North of Lindsay, City of Kawartha Lakes | Federal and Non federal |
Miller Creek Wildlife Area | 17QK11 | 710000 | 4910000 | 82 | Miller Creek Wildlife Area, County of Peterborough | Non federal |
Snelgrove Brook | 17QK11 17QK12 |
710000 710000 |
4910000 4920000 |
82 | East of Bridgenorth, County of Peterborough | Non federal |
Woodview Swamp | 17QK21 | 720000 | 4910000 | 82 | West of Jermyn, County of Peterborough | Non federal |
Birdsalls Creek | 17QK30 | 730000 | 4900000 | 82 | South of Westwood, County of Peterborough | Non federal |
Presqu'ile Bay Marsh 1 | 18TP87 | 270000 | 4870000 | 329 | Middle section of Presqu'ile Provincial Park, Northumberland County | Non federal |
Presqu'ile Bay Marsh 2 | 18TP77 18TP87 |
270000 280000 |
4870000 4870000 |
138 | North end of Presqu'ile Provincial Park, Northumberland County | Non federal |
Presqu'ile Bay Marsh 3 | 18TP87 | 280000 | 4870000 | 189 | Presqu'ile Bay Marshes, Northumberland County | Non federal |
Unnamed Wetland - City of Quinte West | 18TP99 | 290000 | 4890000 | 92 | Northeast of Johnstown, City of Quinte West | Non federal |
Hoards Creek | 18TQ80 | 280000 | 4900000 | 82 | South of Hoards, Northumberland County | Federal and Non federal |
Sawguin Creek Marsh | 18UP18 | 310000 | 4880000 | 125 | North of Ameliasburg, City of Prince Edward County | Non federal |
Sandbanks Provincial Park | 18UP26 | 320000 | 4860000 | 82 | Southeast section of Sandbank Provincial Park, City of Prince Edward County | Non federal |
Marysville Creek Wetland | 18UP29 | 320000 | 4890000 | 131 | East of Big Bay, Tyendinaga Mohawk Territory | Federal |
Unnamed Wetland 1 - City of Prince Edward County | 18UP35 18UP36 |
330000 330000 |
4850000 4860000 |
101 | East of Point Petre Militaries Reserves Site, City of Prince Edward County | Non federal |
Unnamed Wetland 2 - City of Prince Edward County | 18UP39 | 330000 | 4890000 | 82 | North of Solmesville, City of Prince Edward County | Non federal |
Big Sand Bay | 18UP46 | 340000 | 4860000 | 146 | West of Prince Edward Point National Wildlife Area, City of Prince Edward County | Non federal |
Ross Lake Wetland | 18UQ01 | 300000 | 4910000 | 103 | North of Madoc Junction, Hastings County | Non federal |
Parks Creek | 18UQ10 | 310000 | 4900000 | 82 | South of Halston, Hastings County | Non federal |
Thrashers Corners Wetland | 18UQ10 | 310000 | 4900000 | 119 | Northeast of Thurlow, City of Belleville | Non federal |
Hutton Creek Wetland | 18VQ15 18VQ16 |
410000 410000 |
4950000 4960000 |
81 | West of Motts Mills, United Counties of Leeds and Grenville | Non federal |
The Swale Wetland | 18VQ17 | 410000 | 4970000 | 81 | West of Smiths Falls, Lanark County | Federal and Non federal |
Mud Creek | 18VQ35 | 430000 | 4950000 | 138 | West of North Augusta, United Counties of Stormont, Dundas and Glengarry | Non federal |
Upper Canada Migratory Bird Sanctuary | 18VQ97 | 490000 | 4970000 | 81 | Upper Canada Migratory Bird Sanctuary, United Counties of Stormont, Dundas and Glengarry | Non federal |
Mississippi River Snye | 18VR03 | 400000 | 5030000 | 81 | South of Fitzroy Harbour, City of Ottawa | Non federal |
Cooper Marsh | 18WQ39 | 530000 | 4990000 | 81 | West of South Lancaster, United Counties of Stormont, Dundas and Glengarry | Non federal |
Total 10,745 in 54 critical habitat units |
Name of the Critical Habitat Unit |
10 x 10 km UTM Grid ID 1 | UTM Grid Coordinates 2 Easting |
UTM Grid Coordinates 2 Northing |
Critical Habitat Unit Area (ha) 3 | Description | Land Tenure 4 | ||
---|---|---|---|---|---|---|---|---|
|
||||||||
Marais du Chemin du Lac Curley | 18VR05 | 400000 | 5050000 | 79 | North of the city of Gatineau; within Gatineau Park | Federal | ||
Lac La Pêche | 18VR05 | 400000 | 5050000 | 12 | North of the city of Gatineau; within Gatineau Park Federal | Federal | ||
North Onslow (sud-ouest) | 18VR05 | 400000 | 5050000 | 79 | North of the city of Gatineau; within Gatineau Park | Federal | ||
Marais du Lac Brown | 18VR25 | 420000 | 5050000 | 79 | West of Highway 5, near Wakefield; within Gatineau Park | Federal | ||
Marais McLaurin Ouest | 18VR53 | 450000 | 5030000 | 152 | East of the city of Gatineau | Non federal | ||
Marais McLaurin Est | 18VR53 | 450000 | 5030000 | 220 | East of the city of Gatineau | Non federal | ||
Marais des Laîches | 18VR53 | 450000 | 5030000 | 79 | East of the city of Gatineau | Non federal | ||
Marais aux Grenouillettes | 18VR53 18VR63 18VR64 |
450000 460000 460000 |
5030000 5030000 5040000 |
40 | Managed wetland East of the city of Gatineau | Non federal | ||
Marais aux Massettes | 18VR74 | 470000 | 5040000 | 99 | Managed wetland East of the city of Gatineau | Non federal | ||
Marais aux rubaniers | 18VR94 | 490000 | 5040000 | 79 | South of the city of Plaisance | Non federal | ||
La Grande Baie (parc provincial d’Oka) | 18WR73 | 570000 | 5030000 | 79 | In Oka provincial Park | Non federal | ||
Parc-nature du Bois-de-l'île-Bizard | 18WR84 | 580000 | 5040000 | 12 | Regional park in Montreal | Non federal | ||
Grand marais de Beauharnois | 18WR81 | 580000 | 5010000 | 102 | Managed wetland in Beauharnois | Non federal | ||
Marais de Beauharnois N. O. et S. O. – Étang 1 | 18WR81 | 580000 | 5010000 | 79 | Managed wetland in Beauharnois | Non federal | ||
Marais de Beauharnois N. O. et S. O. – Étang 2 | 18WR81 | 580000 | 5010000 | 159 | Managed wetland in Beauharnois | Non federal | ||
Île Saint-Bernard | 18WR92 | 590000 | 5020000 | 213 | Managed wetland in Chateauguay | Non federal | ||
Ruisseau Saint-Jean | 18WR92 | 590000 | 5020000 | 23 | West of Chateauguay | Non federal | ||
Île des Sœurs | 18XR13 | 610000 | 5030000 | 8 | On Nun’s island in the city of Montréal | Non federal | ||
Marais du Bois 440 | 18XR05 | 600000 | 5050000 | 9 | Wetland in the city of Laval | Non federal | ||
Île aux Fermiers | 18XR25 | 620000 | 5050000 | 133 | On an island East of Montréal | Federal | ||
Rivière aux Pins (La Frayère) | 18XR25 | 620000 | 5050000 | 12 | North of Boucherville | Non federal | ||
Rue Alfred (Saint-Amable) | 18XR25 18XR35 |
620000 630000 |
5050000 5050000 |
158 | At the end of Alfred street in Saint-Amable | Non federal | ||
Île Tourte Blanche | 18XR15 | 610000 | 5050000 | 3 | West of Parc national des Îles de Boucherville | Non federal | ||
Pointe à la Meule | 18XR30 18XR31 |
630000 630000 |
5000000 5010000 |
118 | Along the Richelieu river; south of Saint-Jean-sur-Richelieu | Non federal | ||
Baie McGillivray | 18XR30 | 630000 | 5000000 | 102 | Along the Richelieu river; East of l’Île aux noix | Non federal | ||
Rivière du Sud - A | 18XQ39 | 630000 | 4990000 | 328 | East of the Richelieu River near the Quebec/USA border; Downstream portion of the river | Non federal | ||
Rivière du Sud - B | 18XQ49 | 640000 | 4990000 | 130 | East of the Richelieu River near the Quebec/USA border; Upstream portion of the river | Non federal | ||
Anse à l'Esturgeon | 18XQ39 | 630000 | 4990000 | 118 | Along the Richelieu river; south of l’Île aux noix | Non federal | ||
Rivière Richelieu (frontière) | 18XQ28 18XQ38 |
620000 630000 |
4980000 4980000 |
94 | Along the Richelieu river at the Quebec/USA border | Non federal | ||
Baie Missisquoi (rivière aux Brochets) | 18XQ49 18XQ59 |
640000 650000 |
4990000 4990000 |
170 | North of Lake Champlain | Non federal | ||
Ruisseau Black (La Swamp) | 18XQ49 | 640000 | 4990000 | 122 | North of Lake Champlain | Non federal | ||
Étang Streit (Refuge d’oiseaux migrateurs de Phillipsburg) | 18XQ58 | 650000 | 4980000 | 79 | Philipsburg Migratory Bird Sanctuary, east of Lake Champlain | Non federal | ||
Farnham (base militaire 7B) | 18XR51 18XR52 |
650000 650000 |
5010000 5020000 |
10 | North of Farnham | Federal | ||
Farnham (base militaire 6B) | 18XR51 | 650000 | 5010000 | 17 | North of Farnham | Federal | ||
Marais de l’Estriade | 18XR82 18XR83 |
680000 680000 |
5020000 5030000 |
79 | East of Granby | Non federal | ||
Marais de la rivière aux cerises | 18YR21 | 720000 | 5010000 | 140 | In Magog | Non federal | ||
Marais Réal D. Carbonneau | 19BL73 | 270000 | 5030000 | 11 | Managed wetland in Sherbrooke | Non federal | ||
Île du Moine | 18XS50 | 650000 | 5100000 | 122 | Managed wetland on an island East Sorel-Tracy | Federal /Non federal | ||
Baie Lavallière | 18XS50 | 650000 | 5100000 | 91 | Northern portion of the wetland East of Sorel-Tracy | Non federal | ||
Île des Barques | 18XS50 | 650000 | 5100000 | 51 | Managed wetland on an island East of Sorel-Tracy | Federal | ||
Baie Saint-François | 18XS50 18XS60 |
650000 660000 |
5100000 5100000 |
367 | East of Sorel-Tracy | Non federal | ||
Rivière Saint-Joseph | 18XR39 | 630000 | 5090000 | 143 | Southwest of Berthierville | Non federal | ||
Saint-Barthélémy (bassin Ouest) | 18XS51 | 650000 | 5110000 | 18 | Managed wetland south of Saint-Barthélémy | Non federal | ||
Saint-Barthélémy (bassin Est) | 18XS51 | 650000 | 5110000 | 27 | Managed wetland south of Saint-Barthélémy | Non federal | ||
Marais de la Commune | 18XS71 | 670000 | 5110000 | 31 | Managed wetland East of Sorel-Tracy | Non federal | ||
Marais aménagés du Refuge d’oiseaux migrateurs de Nicolet | 18XS71 | 670000 | 5110000 | 317 | Managed wetland West of Nicolet within Nicolet Migratory Bird Sanctuary | Federal /Non federal | ||
Marais Provencher | 19CM07 | 300000 | 5170000 | 19 | Managed wetland in Neuville | Non federal | ||
Étang de la Grande Ferme (Réserve nationale de faune du cap Tourmente) | 19CN61 | 360000 | 5210000 | 3 | Managed wetland in Cap Tourmente National Wildlife Area | Federal | ||
Total 4,615 in 48 critical habitat units |
Name of the Critical Habitat Unit |
10 x 10 km UTM Grid ID 1 | New Brunswick Atlas Block Reference 2 | UTM Grid Coordinates 3 Easting |
UTM Grid Coordinates 3 Northing |
Critical Habitat Unit Area (ha) 4 | Description | Land Tenure 5 | |
---|---|---|---|---|---|---|---|---|
|
||||||||
St. George’s Marsh | 19FL70 19FK79 |
NB Atlas p. 90 square B3 | 670000 670000 |
5000000 4990000 |
38 | The St. George marsh is located in St. George and borders the Trans Canada highway | Non federal | |
Germantown Marsh (Shepody National Wildlife Area) | 20LR66 | NB Atlas p. 82 square C1 |
360000 | 5060000 | 20 | The two northern most controlled water level impoundments (A and A-1) east of the Shepody River within the north east corner of the Germantown Marsh unit (NB Atlas p. 82, Square C1) within the Shepody National Wildlife Area | Federal | |
Bell Marsh | 20LS50 | NB Atlas p. 65 squares B4, B5 |
350000 | 5100000 | 79 | The Bell Marsh borders the north shore of the Petitcodiac river and is situated south of Marsh Junction near Moncton | Non federal | |
Total 137 in 3 critical habitat units |
A strategic environmental assessment (SEA) is conducted on all SARA recovery planning documents, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals. The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally sound decision-making.
Recovery planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that recovery strategies may also inadvertently lead to environmental effects beyond the intended benefits. The planning process based on national guidelines directly incorporates consideration of all environmental effects, with a particular focus on possible impacts upon non-target species or habitats. The results of the SEA are incorporated directly into the recovery strategy itself, but are also summarized below in this statement.
The Least Bittern's preference for a combination of dense emergent vegetation interspersed with areas of relatively shallow open water, often in remote portions of extensive marshes means that protection of its habitat is largely synonymous with general wetland protection, which would benefit several wetland species (e.g., waterfowl, marsh birds, shorebirds) that use these wetlands for foraging, breeding, staging, resting and/or moulting at certain periods of their annual cycle. Maintenance of the hemi-marsh conditions that Least Bitterns prefer is generally consistent with approaches to enhancing waterfowl and marshbirds habitat (Post and Seals, 2000: Tori et al., 2002; Rehm and Baldassarre, 2007).
It should be recognized, however, that several other species at risk including birds [King Rail (Rallus elegans), Yellow Rail (Coturnicops noveboracensis) and Prothonotary Warbler (Protonotaria citrea)], fishes [Lake Chubsucker (Erimyzon sucetta), Spotted Gar (Lepisosteus oculatus), Pugnose Shiner (Notropis anogenus)], turtles [Blanding's Turtle (Emydoidea blandingii), Spotted Turtle (Clemmys guttata)] and snakes (Eastern Foxsnake (Pantherophis gloydi)] may prefer other types of wetland conditions than Least Bitterns. Management actions should take these competing needs into account, while also recognizing the potential for synergistic recovery actions. Wherever possible, natural ecosystem processes should be maintained and allowed to evolve without human interference as these are the processes that marsh inhabitants are naturally adapted to.
The possibility that the present recovery strategy inadvertently generates negative effects on the environment and on other species was considered. The majority of recommended actions are non-intrusive in nature, including surveys and outreach. We conclude that the present recovery strategy is unlikely to produce significant negative effects.
[1] Such predators are probably more abundant than they were previously because of subsidized feeding opportunities around human settlements.
[2] Permanent wetlands include naturally occurring wetlands as well as artificial wetlands managed for conservation purposes.
[3] This criterion is used by the Quebec Conservation Data Center (NatureServe network) and was recommended by the National Least Bittern Recovery Team in 2009 as the minimum requirement to indicate site fidelity.
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