While the poisoning of a golden eagle with carbofuran last month made depressing reading, there were some other raptor stories that were somewhat more exciting. Not least was the reported predation of hen harriers by eagle owls – apparently escapees or deliberate introductions.
Eagle owls have a reputation for killing smaller raptors and especially for taking their chicks. Whilst bird conservation groups have always been enthusiastic about bringing back red kites, goshawks and now sea eagles, they have generally been rather negative about eagle owls because of their propensity to kill off any competing predators.
For others, and for those for whom some of the smaller raptors may be a problem, eagle owls have seemed rather appealing. However, most discussion of the subject has been cut short by the assertion that eagle owls were never part Britain’s fauna in the first place and could never be considered as a bon fide re-introduction. Things now look rather different. In a paper last month in British Birds, John Stewart from the British Museum, no less, reviews the archeological evidence for the bird in Britain and concludes that it seems to have been regularly present here when the climate was right. Probably during the Mesolithic (c10,000 years ago) and maybe even until the Iron Age (around 2,000 years ago). So why not eagles owls then?
While re-introductions are certainly desirable on ecological grounds, they may not always be appropriate to a changed landscape. About 10 years ago the international conservation body IUCN came up with a well thought out set of guidelines on re-introductions. These contain rigorous and quite challenging criteria. In our view no re-introcutions should be attempted without meeting these criteria, and we particularly deplore attempts at re-introductions by allowing birds and mammals to escape from theme parks, so that a re-introduction becomes a fait accompli.