Wildlife officials have begun a massive search for about 100,000 migratory birds that disappeared from the Poyang Lake Nature Reserve after the worst winter weather to hit southern China in five decades.

Luo Shengjin, deputy director of the state-level reserve in the eastern Jiangxi Province, said about 200,000 wild birds had been there before the snow and freezing temperatures began last month, but officials had found only 40,000 since the weather began to ease last week.

Luo said the data could be inaccurate as the monitoring equipment was not advanced and officials could not reach the center of the frozen lake. As the reserve covers only 10 percent of the lake, some of the birds could have migrated to other areas.

Though no mass deaths of fowls have been reported, they were worried about possible losses because the weather had destroyed many of the plants that the birds fed on, said Luo.

Since late January, the reserve had spent 100,000 yuan (13,800 U.S. dollars) to buy grain, corn and vegetables and hundreds of officials had been dispatched to feed the birds.

Ji Weitao, director of the reserve, said they were planning to employ helicopters to search the whole lake as part of a survey.

As China's largest fresh water lake, Poyang is an important habitat for migrant birds to winter over and an internationally significant wetland.

About 95 percent of the world's white cranes, half of the white-naped cranes and 60 percent of swan geese are believed to migrate there each year.

(Xinhua News Agency February 18, 2008)