The forest weasel is an active predator employing a strategy of active hunting and prey searching. The species catches small mammals, birds and their chicks, raids nests, eats insects and sometimes berries or fruits, with its diet including rodents, birds, eggs and insects. Hunting occurs in trees, and potential prey includes capercaillie, pigeons, squirrels, white partridges, grey voles, wall lizards, brown frogs, squirrels and chipmunks. The daily food requirement is from 120 g to 250 g, and the young feed on milk. The eagle is an enemy of the forest weasel.