Space is at a premium in congested Hong Kong - and that goes for the birds, too.
The black-faced spoonbill, which travels southwards to the city during winter, may fly elsewhere if local marshlands such as Mai Po are not protected, bird watchers warn.
The endangered large white birds - found only in Asia - have risen in numbers this year, yet the population in Hong Kong has dropped slightly, an international annual census conducted since 1993 shows.
'The spoonbills live in large flocks and need space. If they are not comfortable in Hong Kong, they will choose to go elsewhere,' said Yu Yat-tung, research manager of the Bird Watching Society. 'Deep Bay in Hong Kong is the second-largest wintering site, after Taiwan, for black-faced spoonbills, so it is crucial that we ease the rapid development around their habitat. Constructing buildings directly next to Deep Bay or right on the edge of the Mai Po marshlands will spoil their habitat.'
The census this year was undertaken by birdwatchers in nine Asian regions from January 13 to 15. They registered 2,693 spoonbills, up from 1,839 last year and 2,347 in 2010.
Bird watchers in Hong Kong and Shenzhen pooled their statistics because of the proximity of the wintering sites, and found spoonbill numbers dropped steadily from 462 in 2010 to 393 this year. 'What we are sure of is the birds did not die in Hong Kong because none of our bird watchers have found their carcasses here,' Yu said. 'But we have found injured spoonbills, mainly from swallowing hooks when trying to eat fish.'
In November, the society launched a system for the public to register sightings of black-faced spoonbills - but only if the bird is wearing a ring on its ankle - a marking left by scientists. 'We hope to disseminate fascinating knowledge about our local marshland celebrity,' Yu said.
The black-faced spoonbill is up to 80 centimetres long and has a long, black, spoon-like beak. Protected under Hong Kong's Wild Animals Protection Ordinance, the birds mate and reproduce in northern countries such as South Korea from March to October, after which they travel south to warmer wintering sites, primarily Taiwan and Hong Kong.
About 10 bird watchers in Hong Kong have registered sightings on the census.