The weasel (Mustela nivalis) is the smallest member of the Mustelidae family and Europe's smallest carnivore. It inhabits a large part of the temperate climate belt in the northern hemisphere. It mainly chooses areas with dense vegetation where there is a sufficiency of small mammals. It feeds on rodents, particularly voles, and more rarely on birds, birds' eggs, fish, frogs and insects. It avoids marshy areas. Weasel numbers are declining in many areas as a result of changes in farming practices.