A weasel hunts mainly by scent and investigates every likely hole and crevice it comes across. It is small enough to follow its favourite prey - voles and mice - down into their underground runs. The victim is killed with a sharp bite to the back of the neck. Prey is usually taken on the ground, but weasels can climb well and sometimes raid a bird's nest box. Weasels are good swimmers too and will chase water voles through the water.
Hunting is done mainly at night, although weasels often hunt during the day too. The favourite food is the field vole and when voles are plentiful there will be a high weasel population. Vole populations fluctuate and when they are low, the weasels do not breed and their populations decrease in turn.
A weasel eats about 28g of food a day - about 25% of its own body weight.Read More: Breeding