White is a strange colour choice for a nocturnal predator. It’s almost as if barn owls want to be seen, says Stuart Blackman.
Not all barn owls are as white as the UK subspecies, though; in much of Europe, they are a much darker rufous colour. Darker birds are generally harder to spot at night, but they can be better seen in moonlight, when their hunts are correspondingly less successful.
White birds, though, are unaffected by the phase of the moon. It seems that a white shape looming suddenly out of the darkness is enough to startle a vole to the point that it freezes with fright (think rabbits caught in headlights), giving the owls more time to make the kill.
So why are some subspecies not white? Perhaps the advantages of startling prey are balanced against the risk of being spotted by mobbing species such as crows.
