The barn owl is not only the world’s most widely distributed species of owl, but is also one of the most widespread of all birds, as it is found on every continent except Antarctica.
Though they occur throughout the tropics, they avoid areas with cold winters. Scotland has the most northerly breeding barn owls in the Northern Hemisphere.
Prolonged periods of snow cover can be devastating for barn owls, leading to many birds starving, as they are unable to find their food.
Mice, voles and shrews form the bulk of the diet, but they will also take young rats, and have even been observed catching fish from ponds.
One of the most unusual feeding records is of a barn owl catching flying hawk moths.
The supply of food dictates the number of eggs laid and the number of chicks that fledge. In good vole years, eggs are laid early and big broods often reared successfully.
Barn owls usually form monogamous pairs, but cases of bigamy, with one male paired with two females, occur occasionally.
Nests are usually in barns or holes in trees, but sometimes quarries or rocky outcrops are used.
In eastern England barn owls are far more likely to nest in trees than in barns.
They readily adopt nest boxes, and this is a proven way of increasing populations in areas where a shortage of suitable nesting sites limits the number of breeding pairs.
No actual nest is made, though the female may form a slight hollow.
The clutch size is highly variable: four to seven eggs are normal, but as many as 14 have been recorded.
If there is a plentiful supply of voles, a pair may have two broods, though the second is invariably smaller than the first.
Like all owls, incubations starts when the first egg is laid. The hatching is asynchronous, which means that each egg hatches 30 days after it was laid, so the smallest chick in a brood may be two weeks younger than its eldest sibling.
Such a hatching system favours the oldest chicks, and these are most likely to survive if supplies of food are scarce.
The chicks will make their first flights when around 50-55 days old, but won’t be independent of their parents for another month.
British barn owls have distinctive white breasts, but in central and eastern Europe they are a shade of dark yellow-orange.
British barn owls are largely resident and seldom move far, but dark-breasted Continental birds are recorded regularly in eastern Britain.
Though they typically hunt in the dark, it’s not unusual to see barn owls hunting during the day, particularly in mid-winter, or when they have chicks to feed.
After many years of decline, the British population is now thought to be increasing slowly.
These owls don’t hoot, but the male has a distinctive shrieking call, often repeated several times.