uring December rough grassland, coastal marshes and verges are magnets for kestrels and barn owls. They can often be seen out hunting in the same places late on midwinter afternoons. But while kestrels hover, scanning the grass below for any movement, barn owls fly low, systematically quartering the habitat on broad, silent wings.
Both species are looking for small mammals, usually shorttailed (field) voles, the abundance of which varies greatly from year to year. In a winter when voles are less plentiful, kestrels and owls compete for food – frequently leading to the falcons attempting to snatch a free meal from the owls. They take advantage of the latter’s slower flight, dashing in to take the prey out of their talons. But the owls don’t give up easily, using their own sharp claws to ward off the attackers – though they often lose the fight.
Kestrels also pick on shorteared owls, and this behaviour is an example of kleptoparasitism – parasitism by theft. However, it is more commonly found in seabirds such as arctic and great skuas, which relentlessly chase gannets, kittiwakes and terns to make them give up their fish.
is a naturalist and broadcaster with a passion for birds of prey: