LANZHOU, Dec. 6 (Xinhua) -- Two rare white-tailed sea eagles have been spotted in northwest China's Gansu Province.

The two eagles were spotted by a local herdsman at Gansu Qilianshan National Nature Reserve. Photos of the two birds were also taken, marking the first time that photos of the birds have been captured from within the reserve.

The white-tailed sea eagle, listed as endangered on the International Union for Conservation of Nature's (IUCN) red list, usually lives at an altitude of 2,500 to 5,300 meters and is mainly found in northern China's Inner Mongolia Autonomous Region, northeast China's Heilongjiang Province and northwest China's Gansu Province.

"White-tailed sea eagles were once spotted in the 1980s in this area, in small quantity. However, they gradually disappeared in the 1990s as a result of a deteriorating natural environment and a decreasing of water area," said Zhao Jun with the nature reserve.

"In recent years, with ecological protection measures such as closing mine companies and hydropower stations, many rare animals are being seen again," he said.