Egrets play in large groups in the wetlands of the Yellow River in Yinchuan, Ningxia Hui autonomous region. [Photo by Li Jing/Provided to chinadaily.com.cn]

Every year around late November, migratory birds came from Siberia to the wetlands of the Yellow River in Yinchuan, Ningxia Hui autonomous region, to spend the winter.

Egrets play in large groups in the wetlands of the Yellow River in Yinchuan, Ningxia Hui autonomous region. [Photo by Li Jing/Provided to chinadaily.com.cn]

In early December, tens of thousands of egrets were photographed playing on the beaches in large groups.

Egrets play in large groups in the wetlands of the Yellow River in Yinchuan, Ningxia Hui autonomous region. [Photo by Li Jing/Provided to chinadaily.com.cn]

According to environmental authorities, there are around 200 lakes, swamps and other wetland areas in Yinchuan, totaling about 500 square kilometers. The improving natural environment has made it an important habitat and transition point for the birds.

Egrets play in large groups in the wetlands of the Yellow River in Yinchuan, Ningxia Hui autonomous region. [Photo by Li Jing/Provided to chinadaily.com.cn]

Some 239 types of birds have been observed in the city's wetlands. Top-level national protected species include black storks, white-tailed sea eagles, golden eagles and Chinese mergansers.