Ruddy ducks are to be shot across the country in a trial to see if they can be wiped out completely, and so save their relative, the endangered white-headed duck of Spain, from being hybridised to extinction.
The decision, announced yesterday by the Environment minister, Michael Meacher, was twice put off by the previous government and will set conservationists head-to-head against animal welfare campaigners.
The Royal Society for the Protection of Birds strongly backed the move but the pressure group Animal Aid said it was "kow-towing to the lunatic fringe of birdwatchers" and accused the Government of "species racism".
Mr Meacher has accepted the advice of a special taskforce he set up on the problem, from the main wildlife agencies and bird organisations, which says that the biggest threat to the white-headed duck's survival is interbreeding with ruddy ducks originating in Britain.
The white-headed duck is one of Europe's rarest birds and is globally endangered, with its world population thought to number no more than 16,000. In Europe, Spain is now its last stronghold. In the 1970s its numbers there were down to 22, but determined conservation work has brought the numbers up to about 1,000.
However, conservationists say the ruddy duck, a closely related bird of North American origin, is rendering this effort worthless because male birds from Britain now fly to Spain, aggressively mate with female white- headed ducks and produce fertile hybrids. They fear the small white-headed population will be bred out of existence. They also fear that other populations, in Turkey and parts of Asia, are also at risk because ruddy ducks have now arrived in these areas.
Trial shooting of some of Britain's estimated 4,000 ruddy ducks will start in the spring at breeding sites in the West Midlands, Anglesey and Fife, the Government said yesterday. It will continue for three years so the possibility of wiping out the birds can be assessed. "This has been a very difficult decision, but has been made on the basis that we have a duty to maintain, as far as we can, the current diversity of species," Mr Meacher said.
Dr Mark Avery, the RSPB's director of conservation, said: "As the society is firmly committed to conserving global biodiversity it supports this unwelcome but necessary task." But Animal Aid said it was a "slaughter to appease anorak birdwatchers".