Mink's exploitation of waterways explains its gradual dispersal. Primarily aquatic, it seldom moves across large areas of land, its routes dictated instead by existing watercourses - rivers, streams or simply drainage ditches.
Intensely solitary, male and female come together briefly during breeding between February and April, forming no pair bond. Females may mate with several males. The young, or "kits", are born in April or May. Kits reach adult size by late August, departing soon after on often-violent struggles to secure a territory.
A gastronomic all-rounder, mink happily devour rabbits, rats, mice, along with eels, waterfowl and coarse fish. In Britain they are blamed for a 90 per cent decline in the last decade in water voles (Ireland has none). Wildlife consultant Dr Chris Smal found fewer mink where their preferred foods, crayfish and rabbits, were scarce - just half a dozen lived on Lough Ennell, or only one per 3km of shore (against one per 0.7km to 1.3km where crayfish abound). Waterfowl were its main food there.
He concluded that mink, foraging for whatever food is available, might tip the balance against survival for prey species already struggling to maintain numbers. They may be scapegoats in media terms, blamed for all manner of wildlife problems, but for already scarce ground-nesting birds, mink moving in next door really is bad news.