American Mink

Ecology of the American Mink (Mustela vison)

Desciption:

Mink males are up to 60 cm long (42cm Body and 18cm tail) females are slightly smaller at 51 cm long (36 cm body and 15 cm tail).
They are glossy dark brown, looking black in certain light. However due to farming history there are some of lighter colour and/or patchy.
They are accomplished swimmers and are often seen in the water, and mistaken for otters.

History:

Habitat:

Mink are generally found on/in or around water of any kind from rivers and streams to canal, ponds and lakers. However they can live away from water should there be sufficient prey, and may even inhabitat urban areas.
Mink will have 2-10 dens in and around their preferred hunting ground, usually in the roots of trees in eroding banks.

Reproduction:

Mating occurs in late February to March, and delayed implantation means the 30 days gestation can extend to 42 days.
4-6 youngs are born in April and May into a vegetation lined den.
At ten weeks they are no longer dependant on the mother for food and accompany her hunting
In August they will have learned to hunt and disperse to there own terratories.

Dispersal:

Although escapees from mink farms became established in the wild between 1932 and 1950, there have been continued illegal releases where large numbers have been released.
Kits dispersing from there mother with settle within 5km (females) or 10km (males) of the den in which they were born.
Mink are now found in varying densities throughout the UK with the exception of some out lying islands, and the far north west of Scotland.

Problems:

Mink are a voracious predator with a wide range of prey. They will predate on: Fish, Birds, Eggs, Rabbits, Water Voles, Crayfish, Eels, and other small mammals.
Being an introduced species many of the prey are not adapted to mink, for example mink are smaller enough to actually fit within water vole burrows, and there fore water voles have no refuge.
Water vole population has been decimated by mink.
The numbers of fish taken by mink are not yet quantified but spawning salmonids would be a ready target for the able swimmers
Ground nesting birds are also a large target for mink who will both kill the sitting bird and eat the eggs

Control:

It is important to undertake surveys to assess the density and size of the Mink population within a catchment
The survey can then be used to set up a trapping strategy, which can be targeted and adapted where necessary.
Encourage the Return of the European otter, as it is believed there presence will reduce the presence of mink in an area (however it will not necessarily guarantee it as there habitat requirements are slightly different)