I’ve seen a few barn owls on Wilden Marsh over the years, including a couple of dead ones. The barn owl is a medium-sized, pale-coloured owl with long wings and a short, squarish tail. The shape of the tail is a means of distinguishing the barn owl from other owl species when seen in the air. The full-grown weight of a barn owl can range from 224 to 710 g (7.9 to 25.0 oz). In general, owls living on small islands are smaller and lighter, perhaps because they have a higher dependence on insect prey and need to be more manoeuvrable. Other distinguishing features are the undulating flight pattern and the dangling, feathered legs. The pale face with its heart shape and black eyes can give the bird a distinctive ghost-like appearance when flying at dusk.
Contrary to popular belief, the barn owl does not hoot (such calls being by owls like the tawny or other members of the genus Strix). It instead produces the characteristic shree scream, ear-shattering at close range, an eerie, long-drawn-out shriek. On more than one occasion the shriek of a close-by barn owl has put the wind up me on a dark marsh night. Males in courtship give a shrill twitter. Both young and old can hiss like a snake to scare away intruders. Other sounds produced include a purring chirrup denoting pleasure, and a “kee-yak”, which resembles one of the vocalisations of the tawny owl. When captured or cornered, the barn owl throws itself on its back and flails with sharp-taloned feet, making for an effective defence. In such situations, it may emit rasping sounds or clicking snaps, produced probably by the beak but possibly by the tongue.
Barn owls are not particularly territorial. They do have a home range in which to forage; for males, this is a radius of about 1 km (0.6 mi) from the nest site and an average size of about 300 hectares. Female home ranges mostly coincide with that of their mates. Outside the breeding season, males and females usually roost separately. Each owl might have around three favoured sites in which to conceal themselves by day. These sites may be visited for short periods during the night. Roosting sites include holes in trees, fissures in cliffs, disused buildings, chimneys, haylofts, and are often small in comparison to the owls nesting sites. As the breeding season approaches, the birds move back to the vicinity of the chosen nest to roost.
The diet of the barn owl can be ascertained by investigating fragments of indigestible matter regurgitated in pellets. Studies have shown that 90% of the owl’s prey in temperate areas is small mammals. In hot, dry, unproductive regions, a great variety of other creatures are eaten. Most prey is terrestrial, but bats and birds are taken, as well as lizards, amphibians and insects.
The average lifespan of a barn owl in the wild is around four years.