Taxonomy: Class: Mammalia; Order: Carnivora; Family: Mustelidae
Description
American mink © Laurie Campbell
The American mink is a carnivorous mammal originally from North America. it was imported into Britain in the 1920s and farmed for its fur. Escapees from fur farms established themselves in the wild by the late 1950s and spread rapidly. The American mink is adapted to a semi-aquatic riparian lifestyle, having partially webbed feet and a water-repellent coat. It is linked to declines in numbers of water voles (Macdonald & Strachan 1999) and can have a damaging effect on nesting birds on offshore islands, game birds and fish stocks (Macdonald & Tattersall 2001).
Further information:
Mammal Society website American mink page.
Conservation status and legislation
Status:
UK: Non-native
World: Least concern (IUCN Red List)
Legislation:
Distribution and abundance
The American mink is found throughout much of the UK, including some of the Western Isles of Scotland. It was not farmed in Ireland until the 1950s, so although feral mink established themselves there later than on the mainland, they are now much more widespread than the limited Irish records visible on the map suggest.
Estimates of American mink abundance (numbers of individuals in the spring) across the UK, from Harris et al. (1995):
Recent trends from the National Gamebag Census
United Kingdom
Index of bag density from 1962 to 2009 (see statistical methods and interpretational considerations).
Error bars represent 95% confidence intervals.
Adequate data for trend analysis were available only from 1962. There has been a significant increase in the bag index between 1962 and 2009 (the increase was rapid between 1962 and 1976), but a significant decrease since 1978. It is possible that the decline is associated with the recovery of otter numbers over the same period, through interspecific competition. Efforts to step up mink control to conserve water voles may also have reduced numbers available for trapping on shooting estates.
Change in American mink bags over time, with 95% confidence limits (see statistical methods):
| Country |
Sites |
Start
year |
End
year |
Change (%)
1961-2009 |
Change (%)
1984-2009 |
Change (%)
1995-2009 |
| United Kingdom |
530 |
1962 |
2009 |
163*
16 to 333 |
-49*
-57 to -40 |
-41*
-49 to -33 |
* significant at P < 0.05
England
Index of bag density from 1962 to 2009 (see statistical methods and interpretational considerations).
Error bars represent 95% confidence intervals.
Adequate data for trend analysis were available only from 1962. There has been a significant increase in the bag index between 1962 and 2009 (the increase was rapid between 1962 and 1976), but a significant decrease since 1978. It is possible that the decline is associated with the recovery of otter numbers over the same period, through interspecific competition. Efforts to step up mink control to conserve water voles may also have reduced numbers available for trapping on shooting estates.
Change in American mink bags over time, with 95% confidence limits (see statistical methods):
| Country |
Sites |
Start
year |
End
year |
Change (%)
1961-2009 |
Change (%)
1984-2009 |
Change (%)
1995-2009 |
| England |
309 |
1962 |
2009 |
226*
17 to 450 |
-33*
-48 to -9 |
-30*
-46 to -6 |
* significant at P < 0.05
Scotland
Index of bag density from 1976 to 2009 (see statistical methods and interpretational considerations).
Error bars represent 95% confidence intervals.
Adequate data for trend analysis were available only from 1976. There has been a significant decline in the index of bag density between 1976 and 2009. It is possible that the decline is associated with the recovery of otter numbers over the same period, through interspecific competition. Efforts to step up mink control to conserve water voles may also have reduced numbers available for trapping on shooting estates.
Change in American mink bags over time, with 95% confidence limits (see statistical methods):
| Country |
Sites |
Start
year |
End
year |
Change (%)
1961-2009 |
Change (%)
1984-2009 |
Change (%)
1995-2009 |
| Scotland |
200 |
1976 |
2009 |
-61*
-75 to -37 |
-63*
-73 to -48 |
-51*
-62 to -40 |
* significant at P < 0.05
Wales
Index of bag density from 1995 to 2009 (see statistical methods and interpretational considerations).
Error bars represent 95% confidence intervals.
Adequate data for trend analysis were available only from 1995. There has been no detectable change in the index of bag density between 1995 and 2009.
Change in American mink bags over time, with 95% confidence limits (see statistical methods):
| Country |
Sites |
Start
year |
End
year |
Change (%)
1961-2009 |
Change (%)
1984-2009 |
Change (%)
1995-2009 |
| Wales |
11 |
1995 |
2009 |
no data |
no data |
-14
-91 to 54 |
* significant at P < 0.05
N Ireland
There are too few bag records of American mink to produce an index graph. 
There are too few bag records of American mink to evaluate rates of change over time
| Country |
Sites |
Start
year |
End
year |
Change (%)
1961-2009 |
Change (%)
1984-2009 |
Change (%)
1995-2009 |
| N Ireland |
Too few sites |
Environmental zones
Change in American mink bags over time, with 95% confidence limits (see statistical methods):
| Environmental zone |
Sites |
Start
year |
End
year |
Change (%)
1961-2009 |
Change (%)
1984-2009 |
Change (%)
1995-2009 |
| Easterly lowlands (England/Wales) |
154 |
1976 |
2009 |
7
-29 to 73 |
-14
-42 to 40 |
-26
-49 to 20 |
| Westerly lowlands (England/Wales) |
79 |
1976 |
2009 |
-36
-66 to 21 |
-2
-39 to 43 |
-8
-41 to 35 |
| Uplands (England/Wales) |
77 |
1980 |
2009 |
-67*
-82 to -31 |
-64*
-75 to -44 |
-51*
-66 to -29 |
| Lowlands (Scotland) |
59 |
1976 |
2009 |
-69*
-85 to -26 |
-68*
-82 to -41 |
-48*
-65 to -16 |
| Intermediate uplands/islands (Scotland) |
28 |
1980 |
2009 |
-70*
-93 to -4 |
-60*
-86 to -34 |
-53*
-78 to -20 |
| True uplands (Scotland) |
114 |
1976 |
2009 |
-53
-75 to 39 |
-55*
-71 to -29 |
-51*
-65 to -30 |
* significant at P < 0.05
Comparison with BBS mammal data
No comparison with the NGC trend is possible because too few American mink records are received through the Breeding Bird Survey (BBS) organised by the British Trust for Ornithology.
Long-term trend from the National Gamebag Census
There are too few bag records of American mink to produce a trend starting before 1962.
References and further reading
- Battersby,J. (2005). UK Mammals: Species Status and Population Trends. Joint Nature Conservation Committee/Tracking Mammals Partnership, Peterborough (JNCC download page).
- Dunstone,N. (1993). The Mink. Poyser, London.
- Harris,S., Morris,P., Wray,S. & Yalden,D.W. (1995). A Review of British Mammals: Population Estimates and Conservation Status of British Mammals Other than Cetaceans. Joint Nature Conservation Committee, Peterborough (JNCC download page).
- Harris,S. & Yalden,D.W. (2008). Mammals of the British Isles: Handbook, 4th edition. Mammal Society, Southampton.
- Macdonald,D.W. & Strachan.R. (1999). The Mink and the Water Vole: Analyses for Conservation. Wildlife Conservation Research Unit & Environment Agency, Oxford.
- Macdonald,D.W. & Tattersall,F. (2001). Britain's Mammals: the Challenge for conservation. People's Trust for Endangered Species, London.
This report should be cited as: Aebischer,N.J., Davey,P.D. & Kingdon,N.G. (2011). National Gamebag Census: Mammal Trends to 2009. Game & Wildlife Conservation Trust, Fordingbridge (http://www.gwct.org.uk/ngcmammals).
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