"There has not been a sighting of a beaver lodge or a beaver in New York City for over 200 years. It sounds fantastic, but one of the messages that comes out of this is if you give wildlife a chance it will come back," said John Calvelli, a spokesman for the Wildlife Conservation Society, which operates the Bronx Zoo.

The Bronx was once synonymous with urban decay and by the 1970s the Bronx River was used as a dumping ground that was virtually choked off with refuse.

But residents and the city government began to clean it up, an effort aided by US$14.6 million in federal funding secured since 2000 by US Rep. Jose Serrano of the Bronx.

Biologists named the beaver Jose in Serrano's honor, Calvelli said on Friday.

Beaver pelts drove the economy of the former New Amsterdam, when New York City was a Dutch trading post full of trappers. The animal appears on the city seal, which in turn appears on the city flag.

Records show the Dutch purchased 7,246 beaver pelts in 1626 and that by 1671 the renamed New York of British rule traded more than 80,000 pelts a year, Calvelli said.