What is an American Mink?
The American Mink is a member of the Mustela genus meaning that it is a mustelid. The American Mink differs from other members of the Mustela genus such as Weasels and Stoats due to its larger size. This mammal is more similar to a type of Marten that the other types of Mustelids as it has a large bushy tail and long body shape. Males usually have a body length of 13 to 19 inches while females are 12 to 15 inches in length. Males also have longer tails (between 6 to 10 inches) compared to females (6 to 8 inches). Their weight often varies with the seasons, but males are known to be heavier at approximately 500-1500 g while females are 400-800 g.
It’s name in Irish is ‘Minc Mheiriceánach’.
Where did it come from?
The American Mink are native to woodland regions of North America and Canada. The species was introduced to Ireland in the early 1950s. Sadly, the mammal was brought to our island for the inhumane purpose of fur farming. It is thought that the first escape of the mammal from a fur farm occurred in the 1960s in Tyrone, Northern Ireland.
Since the first escape, there has been a huge number of deliberate releases and escapes of American Mink in Ireland. Legal fur farming has ceased to operate in Ireland for decades. However, the spread of this non-native species has resulted in most of the island becoming a suitable habitat due to their highly adaptive nature and lack of natural predators in this new environment!
The above images show the origin distribution of American Mink and the national distribution of the species in Ireland.
Do they pose a threat to our native species?
In Ireland, we do not have any native species of Mink. Upon the introduction of the American Mink to our environment, there was no competition from the European Mink (because they are not present in Ireland) and thus a niche was filled within our environment. However, their presence has disrupted the trophic web in Ireland, as the introduction of this predator that does not have a predator itself, allowed for rapid spread of this population in Ireland. This had negative impacts on wild populations of ground-nesting birds and waterfowl as well as smaller mammals such as Wood Mice, Pygmy Shrews and Bank Voles.
Additionally, the presence of this non-native species in Ireland has negative impacts on prey species that are captive for industry, particularly salmon, game birds and poultry. This causes economic damage as individuals who farm these animals are facing economic losses to their livelihood due to American Mink preying on captive stock.
Our native Otter is one of the most direct species in competition with the American Mink for food sources and habitat preferences. That being said, the extent of the impact on Irish Otters is not yet fully understood.
The American Mink is not native to Europe (but there is a European Mink that is!) so this means that there is no legislation protecting the mammal species. This means that American Mink can be trapped and killed in order to reduce their distribution and spread in Ireland, to try restore the natural biodiversity that the presence of this species has affected. However, this seems to be impossible as the species have spread so much that at this stage, eradication is not the answer for Ireland. That being said, control and management of the species can be effective, as the species although alien and invasive, is not creating a huge level of harm to our environment and therefore can be viewed as not an immediate threat to our biodiversity.