Owl food

One of the pleasures of writing this column is being continually surprised, sometimes amazed, by the observations and discoveries people tell me about; and today’s story certainly scored high on my astonishment scale.

Our WNS expert on mammals is not just interested in the more glamorous creatures - otters, badgers, deer etc. He also carefully monitors local populations of mice, voles and shrews. He supplements members’ records by doing his own surveys: setting humane Longworth traps, laying down metal sheets which prove irresistible to small creatures looking for shelter or a family home, and - and here’s the really interesting bit - by dissecting owl pellets. Owls swallow their prey whole and later regurgitate the indigestible bits - bones, skulls, beetles’ wings - neatly packages in a furry wad. Tease these apart, and then all you need is a magnifying lens, a reference book and patience in order to find out what the owl had for dinner and, therefore, what prey items were available.

Recently he was given three pellets found at the Otley Wetlands Nature Reserve: they possibly represent one owl’s single night’s hunting. One pellet was rather large, the others slightly smaller, and he recognised them as coming from a long-eared owl. This bird had caught and consumed three field voles, two common shrews, one wood mouse, a frog and - something else. Among the familiar fragments and tiny skulls were a pair of long bony feet each with a fair stretch of leg bone attached! Each foot had three long toes, the middle toes fully two inches long. Our mammal expert showed them to a couple of bird experts and, without a moment’s hesitation both said, 'Water rail.'

Water rails are shy secretive birds that live in thick waterside vegetation. They belong to the same family as coots and moorhens, though they’re smaller and, needing to insinuate themselves into dense cover, much more slender. Nevertheless, the idea of a medium sized owl - one slightly less bulky than the more familiar tawny owl - managing to gulp down a whole rail - well, it takes some swallowing! Picture the scene: a dark night and the rail snoozing in the reed-bed when - wham - the feathered assassin strikes. It then consumes its victim - first the head with its sharp red bill, then the feathery body, then the long legs and, finally, those big scaly feet. And all in addition to assorted small mammals and one amphibian. A banquet of mediaeval proportions!

PS. During the next week or two I shall be listening for cuckoos. The males generally arrive on Ilkley Moor around St George’s Day and start calling though it’s usually early May before I manage to hear one. Numbers are declining here as elsewhere in the UK so it’s an anxious time.

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