The least weasel mostly eats rodents, for example mice, hamsters, and gerbils. It usually does not attack adult hamsters and rats. Frogs, fish, small birds and bird eggs are almost never eaten. It can attack adult pikas and gerbils. Least weasels sometimes kill prey larger than themselves, such as capercaillie, hazel grouse and hares. In England, the least weasel likes to eat the field vole.