Stoat – Mustela erminea
Habitat: Urban & gardens, rivers and wetland, coastal & marshland, deciduous woodland, grassland, mixed woodland, heathland, arable land.
Description: Long slender body with short legs. Medium to short tail, always with a black tip. Fur ginger to reddish brown above, white to cream below, straight line separating the two colours. Some animals turn white or partially white in winter (known as ‘ermine’).
Size: Males 275-312 mm; females 242-292 mm. Tails 95-140mm
Weight: Males 200-445g; females 140-280g.
Lifespan: Can live up to around 5 years, or 6-8 years exceptionally, but usually don’t survive beyond 1-2 years old.
Origin & Distribution: The stoat occurs throughout Britain and Ireland, living in any habitats at any altitude with sufficient ground cover and food. The stoat’s presence on offshore islands depends upon prey availability.
Diet: Stoats feed mainly on small mammals, especially rabbits and water voles where these are abundant. Small rodents are also taken, supplemented by birds, eggs, fruit and even earthworms when food is scarce.
General Ecology: Stoats don’t like to be out in the open and so tend to hunt along ditches, hedgerows and walls or through meadows and marshes. They search each likely area systematically, often running in a zig-zag pattern. All but the largest prey is killed by a single bite to the back of the neck. The nests of former prey are taken over as dens which may be lined with rodent fur in colder climates. Within its territory the resident stoat will have several dens which it uses periodically. Male and female stoats live separately, marking their territories with scent. These animals will defend their territory against intruders of the same sex, but in spring the males’ system breaks down as they range widely in search of females.
Breeding: Although females (including the year’s kits, which may be only 2 – 3 weeks old) are mated in early summer, they do not give birth until the following spring because implantation is delayed for 9 – 10 months and active gestation is only 4 weeks. A large litter of between 6 and 12 young is born – blind, deaf and barely furred. The female feeds them for up to 12 weeks while the kits are developing into efficient hunters.
Conservation Status: Stoats are legally protected in Ireland but not in the United Kingdom. For many years gamekeepers and poultry farmers have attempted to control stoats. An animal getting into a shed or pen can and will kill every bird it catches. Such attacks are typical behaviour for many small carnivores faced with vulnerable prey. Trapping is less intensive than it used to be (stoats were also taken for their skins, especially when in ermine) but it appears that this had little long-term effect on numbers as natural mortality is usually quite high in stoat populations.