Richard Wilson reports

The death warrant for the North American duck was signed after experts worried that the ruddy male was threatening the endangered Spanish white-headed duck with extinction by breeding with it.

A trial cull costing about �800,000 is to begin around Easter in the West Midlands, Anglesey and Fife.

Environment Minister Micheal Meacher said: "This has been a very difficult decision to take, but has been made on the basis that we have a duty to maintain, as far as we can, the current diversity of species.

"The white-headed duck is in danger of extinction. Action to remove the threat to the species from the ruddy duck is urgently required."

The campaign group, Animal Aid, remains staunchly opposed to a cull. It described earlier plans for such a measure as "immoral, pointless and unworkable".

Earlier plans by the Tory government were shot down amid protests by land-owners.

The ruddy, which was introduced to Britain after 1945, has spread to around 20 countries and has a population of about 4,000.

There are believed to be around 1,000 white-headed ducks in Spain and another 8,500-15,500 in Turkey and further east.