Oct. 28, 2005 — Six Eurasian beavers were released into the English countryside Thursday in an attempt to reintroduce a species that died out in Britain 500 years ago — but this time the biggest threat may be red tape, not hunters.

The adult rodents were caught in Bavaria and released after six months' quarantine into a 15-hectare wooded and lakeland enclosure surrounded by an electric fence in the Lower Mill Estate, part of the Cotswold Water Park.

Split into two groups — a male and two females in each — environmentalists hope the beavers will breed.

Their mostly nocturnal activities will be scrutinized with the use of closed-circuit television cameras in and around two purpose-built straw lodges in the protected area of lakes, wetland and woodland in Gloucestershire, western England.

Soon after their release, however, the project hit a potential snag.

The British government's Department for Environment, Food and Rural Affairs (DEFRA) announced an investigation into whether estate owner Jeremy Paxton held a license to release the animals into the wild.

Paxton could be committing an offense under wildlife laws if the nonnative species escaped from the compound, they said, because of the potential threat to ecosystems, indigenous or protected animals.

Paxton's team insisted the project was legitimate and the animals were not in the wild.

"If DEFRA wants to challenge this then they can," said Derek Gow, who has overseen the project since the quarantine stage.

"The beavers are in a big enclosure, which is protected by a large fence. There is very little chance of them escaping. We are confident that what we have done is perfectly legal and above board. Mr. Paxton's solicitors have looked into this."

The European beaver, which is less destructive than its Canadian cousin and builds fewer dams, was once native to Britain but was hunted almost to extinction in England in the 12th century.

It eventually died out in Scotland in the 16th century, although there have been mounting calls for it to be reintroduced in recent years.

A similar breeding program was attempted in 2001 when 10 beavers were released at a site in Kent, southeast England. But many of the animals died, with those remaining considered too old to breed.