A pair of white cranes has been spotted in a national nature reserve in north China's Hebei Province, according to the local resource protection bureau on Tuesday.

Two white cranes, a species under first-class national protection in China, were seen flying over Hengshui Lake National Nature Reserve. One of them landed on the surface of the water, while the other flew away without stopping, according to Huo Heng Mao, a photographer who took pictures of the two rare birds in the reserve.

As migratory birds attracted by the good ecological environment and abundant food, white cranes stop at the reserve on their way to the north, said Zhang Yuguang of the reserve's resource protection office.

Zhang added that there are only about 5,000 white cranes left in China.

Since the start of the spring migration season, other endangered bird species including Bayer Bouchard, eastern white stork, squawking pelican and white spoonbill have also been spotted in the reserve.

Hengshui Lake, located in Hengshui City, is the only national reserve in the northern plains of China that maintains a complete wetland ecosystem consisting of swamps, waters, mudflats, meadows and forests.