As autumn transitions into winter, migratory birds have flocked together at Hutuo River in Pingshan county, Shijiazhuang, North China's Hebei province, forming a bird watcher's dream.

Standing on the bank of the river, people can see hundreds of birds on the water surface, either chasing and playing with each other, or flying together.

There are more than 30 species of protected wild birds in the area, such as black storks, red-billed gulls, egrets and cormorants.

"The well-preserved ecological environment here has attracted migratory birds to stay for some time," said Gao Yuxi, director of the Shijiazhuang Wildlife Rescue Station, as quoted in a report from local media outlet Hebnews.cn.

The area is also the habitat of Qingtouqianya, or Baer's pochard, which is an extremely rare species of duck that is listed as a first-class protected animal in China.

They have remarkably high requirements for water quality. According to statistics, there are less than 1,500 Baer's pochard in the world, Gao said.

"As long as the environment is polluted, the Baer's pochard will not be here. Here they chose to breed and inhabit, which illustrates that the ecological environment in Shijiazhuang is improving year by year," Gao said.