Barn owls are mainly nocturnal, but may hunt before dusk and around dawn when feeding young and in daylight in winter. In Britain and Ireland, rodents comprise about 90% of their prey, especially short-tailed voles, followed by woodmice and brown rats, but there are regional and seasonal variations.
Prey is normally swallowed whole, with indigestible parts (fur, bones, teeth, feathers etc) regurgitated in large, smooth, blackish pellets, which accumulate at traditional nesting and roosting sites. Barn owls often hunt from exposed perches (eg fence-posts), but also in low flight. They have exceptional hearing and can find prey by sound alone.