Field signs
Weasel droppings are long, thin and twisted, containing fur and feathers, and between 30-60 mm long. Occasionally nests can be found under corrugated iron sheets and are characterised by their droppings and half-eaten prey remains. They have five toes on each foot.
Habits
Weasels have several bouts of activity within a 24 hour period, each lasting up to 130 minutes interspersed with rest periods lasting a similar amount of time. They become more nocturnal in winter. It is a specialist hunter of small mammals with males occasionally taking young rabbits. Birds and birds’ eggs are also commonly taken; very occasionally they may also take reptiles, amphibians and invertebrates. Territory size varies greatly according to food availability, becoming larger as prey density falls.
The habitats they occupy are determined by the presence of small mammal populations. They will use a wide range of habitats offering food and cover, but are less common where small mammals are scarce, such as in woodland with sparse ground cover.
Observations of wild weasels at the Wildwood Trust in Kent indicate that the population appears to have a two or three year cycle. Some years none are sighted, then during other years there will be numerous sightings, particularly around the captive water vole cages where they hunt for house mice. In November 2012, one was caught in a Longworth trap during a small mammal trapping course. It was a large male, caught in the trap with a dead yellownecked mouse which had been killed by a bite to the neck. Presumably the weasel had followed the mouse in there!
Reproduction and life cycle
Adult females come into oestrus in February and may be mated immediately. After a gestation of 36 days up to eight blind, naked kits are born. The kits are generally weaned by May, at which point the female will come into oestrus again. Males and females become sexually mature at three to four months which means they could breed in their first year. As a result, weasels have a prodigious reproductive capacity and are able to increase their population rapidly when food is in plentiful supply.
Distribution, status and conservation
Weasels occur throughout mainland Britain, but are absent in Ireland. They are established on some islands, including the Isle of Sheppey, but not on smaller islands or those without native stoat populations. Population sizes fluctuate widely on an annual basis, linked to prey density and breeding success, especially of voles. Weasels are not protected under UK conservation legislation, but are included in Appendix III of the Bern Convention. Many gamekeepers regard weasels as much less of a threat than stoats and most weasels are killed legally as a by-product of efforts to control stoat numbers.
