What do Barn Owls eat? The Barn Owl’s diet consists mainly of small mammals particularly: Field Voles (45% of total British Barn Owl diet). Common Shrews (20%). Wood Mice (15%). House Mice, Brown Rats, Bank Voles and Pygmy Shrews are also taken. The Mammal Society data has also shown that it’s rare for Barn Owls (in the UK) to take amphibians, invertebrates, birds and bats, although occasional cases have been recorded. Find out more here: https://www.barnowltrust.org.uk/barn-owl-facts/barn-owl-h