Three new bird species have been discovered at Mai Po nature reserve recently. The new birds sighted included a juvenile steppe eagle, which was photographed at the reserve by a local birdwatcher on December 22. The bird has a wide global distribution but is less common in East Asia. It was at first believed to be a greater spotted eagle, which regularly winters in Hong Kong, but further sightings by birdwatchers helped establish its true species. Another first-time visitor to the reserve was a tundra bean goose, which was spotted at the inter-tidal mudflats in Inner Deep Bay on New Year's Day. The goose, widespread globally, is seldom seen wintering as far south as Mai Po. Normally, it travels from breeding grounds in the Arctic to wintering grounds in temperate and subtropical zones such as central China. The latest discovery was an American wigeon, which was found by birdwatchers in Deep Bay on February 25. It was an 'extremely rare vagrant' in Asia, the global conservation body WWF said. 'It is thought this bird mixed with a flock of Eurasian wigeons near the northern breeding grounds, and then migrated with them,' reserve manager Bena Smith said. Mr Smith said the sightings were single birds and it seemed unlikely that climate change - which could disrupt migration pattern - was at play. 'It is possible the steppe eagle was overlooked by birdwatchers and had in fact been in Hong Kong all winter, whereas the tundra bean goose had always been a possible bird for Hong Kong,' he said. 'It is clear that birdwatching and bird photography are becoming a popular hobby in Hong Kong, so it is not surprising that new bird species are being picked up by these visitors to the reserve.' The reserve was closed for 21 days until late February, after a dead heron was found infected with the H5N1 bird flu virus.