LANZHOU -- A total of 627 black storks have recently been spotted in a nature reserve in Northwest China's Gansu province, according to the reserve administration.

During a bird survey, staff at the Heihe Wetland National Nature Reserve in Zhangye city discovered the birds, a species under first-class state protection in China.

A total of 211 bird species have been monitored in the reserve, an increase of 56 from the 1990s, including many rare species, according to statistics.

In recent years, the city of Zhangye has created a more suitable habitat for bird migration due to strengthened ecological restoration efforts.