Migratory birds fly to north China

Migratory birds fly above the Donting Lake in central China's Hunan Province, March 19, 2008. Migratory birds mass to fly to the north after spending winter in the eastern Dongting Lake National Conservation area. (Photo: Xinhua)

Migratory birds fly above the Donting Lake in central China's Hunan Province, March 19, 2008. Migratory birds mass to fly to the north after spending winter in the eastern Dongting Lake National Conservation area. (Photo: Xinhua)

Migratory birds fly in the Dongting Lake National natural reserve in central China's Hunan Province, March 19, 2008. Migratory birds mass to fly to the north after spending winter in the eastern Dongting Lake National Conservation area. (Photo: Xinhua)