Minks are about half the size of Otters and are mainly nocturnal. I concluded that if I was to see one in the middle of the day, there were bound to be lots of them around and that they may be just as much part of the English countryside as the Grey Squirrel.
This letter was prompted by the mass liberation of Minks in the New Forest (August 1998). As collator of the Shorewatch Records for the British Marine Life Study Society, I receive reports of wildlife from the shores around the British Isles. A few years ago I received a disturbing report of the complete decimation of a seabird colony on an island in Dunmanus Bay (near Bantry) on the south coast of Ireland. This occurred at the same time as a Mink Farm had gone bust and all the captive Minks had run wild in the Irish countryside. Doubtless, many of them will have perished, but not before they had caused a lot of environmental damage. The birds deserted their colony the following year.
My estimate is that a Mink would need a territory of at least a square
mile, possibly more, in Sussex where they are probably common. (This is
a guess. It may need drastic revision as numbers of up to 8 per square
kilometre have been recorded in favourable habitats in Canada). It
is difficult to calculate their prevalence. They do not compete with Otters
for food as they take smaller prey (smaller fish and even this is perhaps
doubtful). Birds are important prey as well as Water Voles, Rats, and probably
frogs. They are silent nocturnal killers. It is not known, to me, if they
include Rabbits in their diet. Mink are found all over England always near
water, although they are less aquatic than Otters. They have been present
from at least the 1960s and are probably extending their range.
Heard your broadcast on Radio 5 this morning (Wednesday 12 August 1998),
I thought they gave you rather short shift - How anyone can say that the
mass release of an equivalent to approx. 5 - 10% of the current estimated
mink population will not cause problems to the local wildlife has got to
have little or no real understanding of ecology.
The sudden influx of any extraneous animals especially a primary predator is bond to have a pretty drastic effect on prey species. Mink are notorious, very efficient killers and are one of the few species that are known to kill without the 'hunger' motivation - there are only two others to my knowledge the wolverine and US!
I have seen the effect that mink has had on breeding populations of
birds especially ground breeding and wetland species - at WWT Arundel.
They have had quite a battle raging for several years to protect the endangered
species AND the visiting wild species that breed there.
Locally to here the water vole population - partly due to habitat loss and some pollution - has been devastated by the mink population along the Lea and Stort Valleys.
One has only to look at the numerous other instances where extraneous predators have been established around the world - rats, cats, dogs etc. introduced to many islands in the Caribbean, Pacific, New Zealand have caused significant losses in wildlife.
Rye Harbour Nature Reserve