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BC Conservation Data Centre: Conservation Status Report

Neogale frenata altifrontalis
Long-tailed weasel, altifrontalis subspecies

 
Scientific Name: Neogale frenata altifrontalis
Scientific Name Synonyms: Mustela frenata altifrontalis
English Name: Long-tailed weasel, altifrontalis subspecies
   
Provincial Status Summary
Status: SH
Date Status Assigned: March 18, 2011
Date Last Reviewed: March 25, 2024
Reasons: This subspecies inhabited a small and restricted range in British Columbia, but there are no recent records. Urbanization of their provincial range continues, and agriculture and forestry practices also have the potential to remove and fragment weasel habitat.
 
Range
Range Extent: ZB = 0 to 250 square km
Range Extent Comments: Formerly found in the Fraser Delta region in British Columbia (Forbes 1994), which included areas west of Hope to the coast and north to Harrison Lake. This subspecies reportedly preferred open grassland and river bottom habitats in the region. There is a record from 2018 about 120 km to the south of the BC border (iNaturalist; accessed March 7, 2024)
Area of Occupancy (km2): U = Unknown
 
Occurrences & Population
Number of Occurrences: ZA = 0 - 5
Comments: The last collection was made at Vedder Crossing in 1937. There are other historical specimen records from Vedder Crossing, Cultus Lake, Lihumitson Park and Chilliwack (Cowan and Guiget 1965).
Number of Occurrences with Good Viability / Ecological Integrity: Rank Factor not assessed
Number of Occurrences Appropriately Protected & Managed: A = None
Comments: No extant occurrences, so none protected. There are, however, several protected areas within this subspecies' former range; e.g. Cultus Lake Provincial Park, Sumas Mountain Provincial Park, Aldergrove Lake Regional Park.
Population Size: U = Unknown
Comments: Abundance is not known. Long-Tailed Weasels are difficult to census, due to their low densities and large movements (Fagerstone 1987).
 
Threats (to population, occurrences, or area affected)
Degree of Threat: BD = High - low
Comments: The rapid, ongoing urbanization of the lower Fraser Valley is the single greatest threat to this subspecies. In rural and backcountry areas, grazing and forest practices are also of concern. Grazing of domestic animals can reduce the abundance of prey in an area. Uncontrolled forest fires and trapping may have a negative impact on this animal. Agricultural practices where pesticides are used or wetlands are drained may also affect habitat and prey supply. Trapping in the Puget Trough area of Washington state found Mustela frenata (presumably M. f. altifrontalis) more common in closed-canopy forests with little understory, abundant coarse, woody debris and high numbers of flying squirrels (Wilson and Carey 1997). This type of forest is rare and becoming rarer within this subspecies' range.
 
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: U = Unknown
Comments: Given the large amount of urban development in the lower mainland, it is assumed that suitable habitat is becoming more limited.
Long-Term Trend: U = Unknown
Comments: Unknown, but presumed to have declined.
 
Other Factors
Intrinsic Vulnerability: U=Unknown
Environmental Specificity: Rank Factor not assessed
Other Rank Considerations:
 
Information Gaps
Research Needs:
Inventory Needs: If there are going to be any long-term management strategies to protect this subspecies, inventories are needed to determine the number of extant occurrences (Forbes 1994), since current information on numbers and habitat requirements are inadequate.
 
Stewardship
Protection:
Management: Trapping should be limited, and any remaining large areas of mature forests and areas of rough pasture in an uncultivated state should be protected. In addition to providing large areas of undisturbed pasture and forest habitat, Forbes (1994) believes that small clearcuts, riparian protection, and connecting blocks of uncut timber would benefit this weasel. Slash piles, snags, and downed logs should be left for foraging areas after clearcuts occur. Forbes (1994) also believes that controlling forest fires would benefit this species.
 
Version
Author: Ramsay, L. (2024), S. Cannings and L. Ramsay (1998)
Date: March 07, 2024
 
References
Banfield, A. W. F. 1974. The mammals of Canada. University of Toronto Press, Toronto, Canada. 438 pp.
British Columbia Conservation Data Centre. 1998. Unpubl. files. B.C. Minist. Environ., Lands and Parks, Resour. Inventory Branch, Victoria, BC.
Carey, A. B., S. P. Horton, and B. L. Biswell. 1992. Northern spotted owls: influence of prey base and landscape character. Ecological Monographs 62:223-250.
Cowan, I.M. and C.J. Guiguet. 1965. The mammals of British Columbia. Handb. No. 11, B.C. Prov. Mus., Victoria. 414pp.
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.
Forbes, R.D. 1994. Draft wildlife habitat areas species prescription, Washington Long-tailed Weasel. B.C. Minist. Environ., Lands and Parks, Cranbrook. 3pp.
Nagorsen, D. 1990. The mammals of British Columbia: a taxonomic catalogue. Mem. No. 4. Royal B.C. Mus., Victoria. 140pp.
Nagorsen, D. W. 2005b. The rodents and lagomorphs of British Columbia. Royal B.C. Mus. Handb., Victoria, BC. 410pp.
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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Suggested Citation:

B.C. Conservation Data Centre. 2024. Conservation Status Report: Neogale frenata altifrontalis. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Nov 5, 2026).