The Polecat (Mustela putorius)
FACTS AND FIGURES
Recognition: Blackish guard hairs and yellow under fur on the body, giving ‘black and tan’ appearance; banded “bandit” face: pale muzzle, ear tips and ‘eyebrows’, with a broad dark band around the eyes; darker legs and belly, short fluffy tail; is the size of a ferret. Head/body length: males 33-45cm, females 32-39cm; tail length: 12-19cm Weight: Males weigh around 0.8-1.9kg, females 0.5-1.1kg. Lifespan: Polecats have lived up to 14 years in captivity, but in the wild most probably die before they are five years old. Diet: Rabbits favoured in the summer, common rats in the winter, but other prey items such as frogs or birds can be taken.
Polecats are found throughout Wales, the midlands and parts of central southern England, and are spreading steadily from these areas. There are isolated populations in Cumbria and Caithness, which probably result from unofficial releases. Once, polecats were widespread throughout Great Britain, but were nearly exterminated by 1915. They never occurred in Ireland, or on the outer islands. Although they occur in a wide range of habitats, polecats prefer lowland areas. When they were confined to Wales, valleys and farms were favoured; as they have spread out into England, farmland with hedgerows and small woods is preferred. Polecat dens are commonly in rabbit burrows, especially in summer, but they frequently move into farmyards in winter, when they may den in hay bales, under sheds and in rubbish tips. This change of habitat reflects their changing diet through the year. In summer, rabbits are a major food, and polecats are quite slender enough to hunt them within their burrows. In winter, common rats become a favoured food, and sites, like farmyards and rubbish tips, that have good rat populations become more usual habitats. Polecats do however kill a wide range of prey. Frogs may be important in spring, when they have gathered to spawn. Birds may be taken, and the polecat was once considered a menace to farmyard poultry (a possible explanation of the name is the Anglo-French poule-chat, poultry-cat) Polecats have territories that vary in size according to habitat and food availability. For males they have been measured at 16-500 ha, and for females about 25-375 ha, using radio-tracking. Territoriality seems weaker in polecats than other mustelids, perhaps because they move around more to exploit seasonally abundant food sources. There are often piles of scats near den sites, but little evidence that scats are left around the territory to defend its borders. Polecats have scent glands either side of the anus, and they produce a pungent, repellent scent. Indeed, they can execute a hand-stand and spray the scent backwards, rather like a skunk. The female has just one litter a year, and young polecats are born blind and hairless, in litters of 5-10, in late May-early June. They begin to take meat from 3 weeks, and stay with their mothers for 2-3 months. They reach adult size by the autumn, and breed at one year old. Mating is rough, the bigger male grasping the female’s nape. Pregnancy is direct (no delayed implantation, as in stoats or pine martens), lasting 40-43 days. Male polecats play no direct part in rearing the young.
In addition to its protection under the Wildlife and Countryside Act 1981, the polecat has recently (2007) been added to the list of UK BAP mammals, protected as species of principal importance for the conservation of biological diversity in England under Section 74 of the Countryside and Rights of Way (CRoW) Act 2000. Until the 19th Century, polecats were found throughout much of mainland Britain and the Isle of Wight. Habitat fragmentation, persecution by gamekeepers and being killed for their fur drastically reduced this distribution. The polecat population was reduced to about 5,000, but is now more than 46,000. One worrying problem is the extent to which they might suffer from secondary poisoning from rodenticides. Rats are commonly killed by anticoagulant poisons when they infest homes and farms, but there is an evident risk to polecats from eating sick, dying rats. It is not known how serious this might be at the level of the polecat population. Prime habitats for polecats seem to be farmland with abundant rabbits; trapping suggests densities around 1/km2. As they spread further into England, the increasing density of roads and road traffic is a threat, and seems to be slowing their spread into both northern and SE England.
Birks, J.D.S. (2008). The polecat survey of Britain 2004-2006. The Vincent Wildlife Trust, Ledbury. Birks, J.D.S. & Kitchener, A.C. (1999). The distribution and status of the Polecat Mustela putorius in Britain in the 1990s. The Vincent Wildlife Trust, London. Harris, S. & Yalden, D.W. (2008) Mammals of the British Isles: Handbook, 4th edn. The Mammal Society, Southampton.