NANNING, Feb. 12 (Xinhua) -- Four spoon-billed sandpipers, members of a rare and endangered species, have been spotted in south China's Guangxi Zhuang Autonomous Region.

Spoon-billed sandpipers are listed as "critically endangered" by the International Union for Conservation of Nature.

The four birds were found during a survey of waterbirds wintering in the city of Qinzhou, said Zhang Dong, chief engineer of the municipal oceanic bureau.

A total of 20,000 to 30,000 waterbirds were observed during the two-day survey, including 148 black-headed gulls and other rare birds.

Qinzhou has invested nearly 100 million yuan (about 15.49 million U.S. dollars) in conducting marine ecological restoration in recent years.