BIRD experts are trying to find out whether huge owls have become established in the wild in Britain after escaping from zoos.

Eagle owls, which have a 6ft wing span and are capable of carrying off prey the size of young deer, have never bred naturally in the UK, but now they have gained a foothold in the countryside.

Experts who compile reports on non-native birds breeding in the UK are appealing for details of all sightings of the owls.

So far, the only definite information is that a pair that set up home on secluded Army training ranges on moorland near Catterick Garrison, North Yorkshire, has reared at least 13 young since 1996 - but they may no longer be alone.

Dr Malcolm Ogilvie said: "We are wondering what has happened to the offspring. They are no longer in the territory occupied by their parents, which raises the possibility that some may have found mates and be nesting elsewhere.

"Eagle owls occur widely in captivity in Britain and apparently they breed quite well in zoos and collections.

"However, they also seem to be good at escaping, so finding mates that are not their brothers or sisters should not be too difficult for the birds reared in the wild.

"If some of the 13 young that are known to have been reared are now themselves raising offspring it is likely to be in similarly remote areas so, in view of their elusive nature, we are not particularly surprised that it has not already been reported to us."

Dr Ogilvie hopes bird-watching clubs that often do not bother to log sightings of escaped zoo birds will tell him about any eagle owl reports in their area.

Anyone interested in helping Dr Ogilvie can write to him at Glencairn, Bruichladdich, Isle of Islay, Scotland.