By Alex Kirby BBC News Online environment correspondent

A small bird thought to have become extinct years ago has been rediscovered in Brazil.

The bird, the golden-crowned manakin, was first found in 1957 - also the year it was last seen.

Ornithologists say its reappearance means there is more hope of finding other species lost for decades.

But they are worried that threats to the bird's rainforest habitat may mean its hold on life will be short.

The manakin was discovered 45 years ago by the German-born ornithologist Helmut Sick, in Para state in southern Amazonia. Two years later it was officially recognised as a distinct species.

Several unsuccessful attempts to find the bird have been made since 1957. Then, within the last week, two Brazilian scientists rediscovered it by chance.

The two, Fabio Olmos and Jose Fernando Pacheco, were carrying out an environmental survey along the line of a new road being built for the logging industry.

They found the bird - a single male - several hundred kilometres from Sick's original discovery of five birds.

Not safe yet

Fabio Olmos said: "We were thrilled to find the lost manakin - quite distinctive from other manakins.

"The local economy is based on logging and cattle-ranching on cleared land. The Brazilian Government is encouraging colonisation but has no way of controlling loggers, squatters, colonists and gold miners once access is created.

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"Forest destruction will remain a major threat to the long-term survival of this beautiful bird and other wildlife of the area."

BirdLife International, an alliance of conservation groups working in more than 100 countries, is setting up a network of conservationists in Brazil, including the manakin's finders.

Alison Stattersfield of BirdLife said: "This is tremendous news, but there are genuine concerns that the manakin's habitat is under threat from the continued destruction of the fantastic Amazonian rainforest."

Gone for a century

Ade Long of Birdlife told BBC News Online: "More new bird species have been reported from Brazil in the last 10 years than from anywhere else on Earth.

"So the manakin's reappearance encourages us not only to keep looking out for vanished species, but to hope that there are entirely new ones for us still to find.

"And Jose Fernando Pacheco has a very good record. He's rediscovered two other lost species in the last decade.

"One 'lost' bird he was involved with, the kinglet cotinga, which looks like a goldcrest, hadn't been seen since the 19th Century."