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BC Conservation Data Centre: Conservation Status Report

Mustela haidarum
Haida Ermine

 
Scientific Name: Mustela haidarum
Scientific Name Synonyms: Mustela erminea haidarum
English Name: Haida Ermine
English Name Synonyms: Ermine, <i>haidarum</i> subspecies
   
Provincial Status Summary
Status: S3
Date Status Assigned: March 28, 2024
Date Last Reviewed: March 28, 2024
Reasons: In BC this species is only found on Haida Gwaii in low numbers with threats that are wide in scope.
 
Range
Range Extent: E = 5,000-20,000 square km
Range Extent Estimate (km2): 15,545
Range Extent Comments: This species is only found on Haida Gwaii in B.C. with records from Graham, Moresby, Louise and Burnaby Islands (Reid et al. 2000) and possibly Kumdis Island (D. Burles pers. comm. 2005). The estimated range extent, based on CDC element occurrences as 2021, is 15,545 km2. The only other known place in the world where this species occurs is Prince of Wales Island in Alaska.
Area of Occupancy (km2): F = 126-500
Area of Occupancy Estimate (km2): 1404
Area of Occupancy Comments: Area of occupancy is approximately 1,404 km2 calculated from 351 4-km2 grid cells (based on CDC mapped occurrences as of 2021). Many areas of Haida Gwaii without ermine records may indicate lack of human presence to observe ermine rather than an absence of ermine. Ermine appear to select for lower elevations (Reid et al. 2000), with most records from the CWHwh1 biogeoclimatic subzone.
 
Occurrences & Population
Number of Occurrences: C = 21 - 80
Comments: There are 31 occurrences mapped by the BC CDC, several observations in iNaturalist (accessed February 2024) and areas of difficult too access, unsurveyed, suitable habitat. so likely approximately 50-60 total occurrences. This is using NatureServe's separation distances of 5km suitable habitat and 1km unsuitable habitat.
Number of Occurrences with Good Viability / Ecological Integrity: U = Unknown
Number of Occurrences Appropriately Protected & Managed: U = Unknown
Comments: One sighting is extant from Gwaii Haanas National Park Reserve and Haida Heritage Site (Ikeda Cove) in 2001 (D. Burles pers. comm. 2005). Ermine have also been sighted in Naikoon Provincial Park (Reid et al. 2000).
Population Size: C = 250 - 1,000 individuals
Comments: Likely fewer than 1000 individuals (COSEWIC 2015), based on surveys, trapping and observations. This species appears to occur in very low densities (Foster 1965; Cowan 1989; Reid et al. 2000). Between 1992 and 1998, Reid et al. (2000) used a variety of techniques in attempts to inventory this species, largely without success: 2 captures in 6765 trap nights between 1992 and 1995; zero records while snow tracking (22km by foot, 900 by road in 1998/995) and zero records with track plate stations (2692 nights in 1997/98).
 
Threats (to population, occurrences, or area affected)
Degree of Threat: CD = Medium - low
Comments: The primary threats to this species are by vegetation change due to understory modification by introduced Black-tailed deer (Odocoileus hemionus columbianus), interspecific competition and predation by Marten, and mortality due to accidental trapping (COSEWIC 2015).

Introduced Black-tailed deer (Odocoileus hemionus columbianus) have had a large impact on ermine habitat on Haida Gwaii. Deer have removed or significantly decreased understory and ground cover vegetation across much of Haida Gwaii (Banner et al. 1989; Daufresne and Martin 1997). Elsewhere in coastal cedar-hemlock forests, ermine are are most common in sites with substantial understory and ground cover (Wilson and Carey 1996; Mowat et al. 2000). Loss of ground cover and understory also has implications for primary ermine prey; dusky shrews (Sorex monticolus), Keen's mouse (Peromyscus keeni) and ground-nesting birds. Deer, as well as introduced red squirrels and rats (Rattus spp.), have also likely led to a significant increase in native marten (Martes americana) on Haida Gwaii. A higher marten population increases both inter-specific competition with ermine for food sources and possible incidental ermine predation. House cats (Felis domesticus) may also be significant predators of ermine. Two of ten sightings between 2003 and 2005 were house cat kills (A. Cober pers. comm. 2005). Red squirrels, rats and introduced raccoons (Procyon lotor) also compete with ermine for food resources (COSEWIC 2015).

Forest management practices likely have some impacts on ermine, though probably limited. Logging affects approximately 25% of the CWHwh1 forests on Haida Gwaii (Park Canada Agency 2011) and Haida Ermine do not appear to avoid harvested areas as over 50% of ermine sightings have been in second growth or unforested areas (Reid et al. 2001).. However, extensive browsing by Deer on logged areas could reduce vegetative cover in cutblocks and render Haida Ermine more vulnerable to predation (Parks Canada Agency 2011).
 
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: U = Unknown
Comments: Lack of data precludes reliable short-term trend information.
Long-Term Trend: U = Unknown
Comments: There is speculation that ermine were probably never numerous on Haida Gwaii (Hall 1951; Foster 1965; Cowan 1989), however there are also some evidence that at one time they were found throughout the islands (Hatler et al. 2008). Evidence suggests that the species has declined since the introduction of red squirrels (Tamiasciurus hudsonicus) around 1950 (Edie, 2001; Burles et al. 2005). Ermine pelts used in traditional Haida headdresses were from continental ermine, obtained through trade.
 
Other Factors
Intrinsic Vulnerability: C=Not intrinsically vulnerable
Comments: Ermine populations are highly variable elsewhere. Reproductive output is closely tied to food abundance; when prey are at very low densities, ermine are unable to produce a litter (Korpimaki et al. 1991; King 1985; Erlinge 1983). They are able to respond quickly to prey abundance: newborn females can be impregnated shortly after birth while their eyes are still closed (King et al. 2003) and litter size can be as high as 13 (Fagerstone 1987). However ermine exhibit delayed implantation of nine to ten months and produce only one litter a year. Ermine are highly tolerant of human presence. Many sightings of this species are in immediate or close proximity to human habitation (A. Cober pers. comm. 2005).
Environmental Specificity: C=Moderate. Generalist or community with some key requirements scarce.
Comments: M. erminea is a holarctic species that utilizes a wide variety of habitats. On Haida Gwaii, Reid et al. (2000) used sightings data to conclude that ermine are similarly habitat generalists. Possible preferences inferred from sightings data are for low elevations in close proximity to ocean, rivers, creeks and estuaries. Ground cover and understory vegetation are likely important stand-level habitat features (Wilson and Carey 1996; Mowat et al. 2000).
Other Rank Considerations: This species is endemic to Haida Gwaii and Prince of Wales Island, Alaska, one of three recognized ermine species in the world.
 
Information Gaps
Research Needs: 1. Basic biology diet, causes of mortality, habitat preferences, critical habitat 2. Interactions among ermine, marten and red squirrels: Do increased marten populations limit ermine? 3. Genetic flow between islands with resident ermine. 4. Impact of deer on ermine; are ermine populations higher in areas / islands without deer?
Inventory Needs: 1. Develop an effective method for determining presence / absence of ermine and estimating population size. 2. Determine distribution throughout islands from which they are known. Are ermine continuously distributed or are they patchy subpopulations?
 
Stewardship
Protection: Uncertain at this point. Gwaii Haanas National Park Reserve and Haida Heritage Site is 1495 sq. km (15% of Haida Gwaii), but has only one record of ermine. Naikoon Provincial Park is 726 sq km (7.3% of Haida Gwaii and 11.4% of Graham Island).
Management:
 
Version
Author: Ramsay, L. (2024), K.Meyers (2014), I. Adams (2005)
Date: February 29, 2024
 
References
Banfield, A.W.F. 1974. The mammals of Canada. Univ. of Toronto Press, Toronto, Can. 438pp.
Banner, A., J. Pojar, J.W. Schwab, and R. Trowbridge. 1989. Vegetation and soils of Haida Gwaii: recent impacts of development. pp. 261-279 in G.G.E. Scudder, and N. Gessler, eds. The Outer Shores. Queen Charlotte Islands Museum Press. 327pp.
Burles, D.W., A.G. Edie, and P.M. Bartier. 2005. Native land mammals and amphibians of Haida Gwaii with management implications for Gwaii Haanas National Park Reserve and Haida Heritage Site. Parks Can. Tech. Rep. in Ecosystem Sci. Rep. No. 40. Queen Charlotte, BC.
Byun, S.A. 1998. Quaternary biogeography of western North America: insights from mtDNA phylogeography of endemic vertebrates from Haida Gwaii. PhD Dissertation. Univ. Victoria. Victoria, BC.
Colella, J.P., L.M. Frederick, S.L. Talbot and J. A. Cook. 2021. Extrinsically reinforced hybrid speciation within Holarctic ermine (Mustela spp.) produces an insular endemic. Diversity and Distributions 27:747-762
Cowan, I.McT. 1989. Birds and mammals on the Queen Charlotte Islands. Pages 175-186 in G.G.E. Scudder, and N. Gessler, eds. The Outer Shores. Based on the Proc. Queen Charlotte Islands First Int. Symp., Univ. B.C., Vancouver. 1984. Queen Charlotte Islands Mus., Skidegate, BC. 327pp.
Daufresne, T., and J-L. Martin. 1997. Changes in vegetation structure and diversity as a result of browsing by a large herbivore: the impact of introduced black tail deer in the primary forest of Haida Gwaii. Laskeek Bay Rep. on Scientific Activities. 7:2-26.
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Fagerstone, K.A. 1987. Black-footed ferret, long-tailed weasel, short-tailed weasel, and least weasel. Pages 549-573 in M. Novak, J.A. Baker, M.E. Obbard, and B. Malloch, eds. Wild Furbearer Management and Conservation in North America. Ont. Minist. Nat. Resour., Toronto.
Fleming, M.A., and J.A. Cook. 2002. Phylogeography of endemic ermine (Mustela erminea) in southeast Alaska. Mol. Ecol. 11:795-807.
Foster, J.B. 1965. The evolution of the mammals of the Queen Charlotte Islands, British Columbia. No.14. Occas. Pap., B.C. Prov. Mus., Victoria, BC.
Haida Ermine Recovery Group. 2003. Draft National recovery strategy for Short-tailed weasel, haidarum subspecies, (Mustela erminea haidarum). Recovery of Nationally Endangered Wildlife (RENEW) Secretariat. Hull, PQ.
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Hatler, D.F., Nagorsen, D.W. and Beal, A.M., 2008. Carnivores of British Columbia (Vol. 5). Victoria, British Columbia, Canada: Royal BC Museum.
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King, C.M. 1985. Interactions between woodland rodents and their predators. Symp. Zool. Soc..London. 55:219-247.
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Nagorsen, D. 1990. The mammals of British Columbia: a taxonomic catalogue. Mem. No. 4. Royal B.C. Mus., Victoria. 140pp.
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Parks Canada Agency. 2011. Recovery Strategy for the Ermine, haidarum subspecies (Mustela erminea haidarum), in Canada. Species at Risk Act Recovery Strategy Series. Parks Canada Agency. Ottawa iv + 3 pp + Appendices.
Preble, E.A. 1898. Description of a new weasel from the Queen Charlotte Islands B.C. Proc. Biol. Soc. Wash. 12:169-170.
Reid, D.G., et al. 2000. Inventory of the Queen Charlotte Islands Ermine. Pp. 393-406 in L.M. Darling, ed. 2000. Proc. Conf. on the Biology and Manage. Species and Habitats at Risk, Kamloops, B.C., 15-19 Feb., 1999. Vol. 1; B.C. Minist. Environ., Lands and Parks, Victoria, BC, and Univ. College of the Cariboo, Kamloops, BC. 490pp.
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Wilson, T.M., and A.B.Carey. 1996. Observations of weasels in second-growth Douglas-fir forests in the Puget trough, Washington. Northwest Nat. 77:35-39.
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.

Suggested Citation:

B.C. Conservation Data Centre. 2024. Conservation Status Report: Mustela haidarum. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Apr 3, 2026).