The eagle owl, with its six-foot wingspan, is one of more than a score of bird species establishing themselves in the wild after escaping from collections of exotic avifauna. An expert warned yesterday that some of them could become pests, or pose serious problems for other wildlife.
Top of the list is the eagle owl. There is nothing in British bird life quite like Bubo bubo, whose regular habitat is rugged hill or mountain country in Europe, north Africa and Asia. They are huge barrel-shaped brown birds, standing over 2ft high with prominent feather tufts giving them a horned appearance. They hunt by ambushing passing prey or pouncing on birds - as big as eider ducks. Fish can be taken by plunge-diving or hovering.
Successful breeding of the birds has occurred for the past two years on a secluded army training range near Catterick Garrison, North Yorkshire.
"Eagle owls occur widely in captivity in Britain," said Dr Malcolm Ogilvie, secretary of the Rare Breeding Birds Panel. "They seem to be quite easy to keep in this state, they breed quite well, apparently, and, unfortunately, they also seem to be good at escaping."
Dr Ogilvie added: "There is no evidence they have ever lived naturally in Britain and if they became established here through escaping from captivity, they could become a nuisance and would not be welcome."
The panel has produced a report warning that a range of alien birds nesting in the UK is posing potentially serious problems. The report focuses on 22 species that are gaining footholds, including Australian black swans, Asiatic bar- headed geese, Arctic-nesting snow geese, barnacle geese, and tropical rose-ringed and monk parakeets.
Rose-ringed parakeets (Psittacula krameri) nesting in south-east England are known to damage fruit crops. They could also compete with native species for food and nest sites. Monk parakeets (Myiopsitta monachus) could present similar problems. Birds from an aviary at Tiverton, Devon, have nested in the area in recent years.
n Eight British seabird colonies are to be closely monitored under a scheme launched today amid fears that their numbers are shrinking because of sandeel fishing. Every year Danish trawlers in the North Sea net about one million tons of the fish, which form the staple diet of the kittiwake, the Arctic tern, the puffin and other birds.
Exotic Birds Gone Native
Rose-ringed parakeet (Psittacula krameri ): Native to Africa and India, was added to British List in 1983 after feral breeding in London's outer suburbs. These 16in-long green birds are now widespread in the South- east.
Snow goose (Anser caerulscens): Nests in Arctic, winters in US, with a few straying across the Atlantic to Europe. Two pairs bred on the Scottish island of Coll and up to 50 have been recorded there and on neighbouring Mull.
Wood duck (Aix sponsa): Wild population mainly in east US, Canada. Attempts to naturalise in Britain made in 1870s; free-flying birds released in Surrey in late 1960s. The report says 24 pairs were found in Kent in 1996.