A nature reserve in central China's Hunan Province had attracted 31,200 migratory birds this winter as of Wednesday.

Staff at the Hengling Lake Nature Reserve in Xiangyin County observed 32 kinds of birds, including seven black storks, four white cranes, 170 grey cranes, and 420 little swans all under national protection.

The nature reserve is part of the wetland of Dongting Lake, China's second largest freshwater lake.

Li Sijun, a staffer at the reserve, said that more and more migratory birds have flown to the reserve for wintering, which shows that the environment around the lake has kept improving.

In recent years, the local government has carried out wetland restoration projects, launched a crackdown on poaching, and made every effort to create a safe habitat for migratory birds.