XINING -- Patrollers have rescued eight Tibetan antelope calves in China's high plateau Hoh Xil national nature reserve in Qinghai Province, local authorities said Wednesday.

The calves were discovered in late July after their mothers delivered them in Zonag Lake and tried to bring them back to their original habitat, according to Hoh Xil's Sonam Dargye protection station.

Every summer, large groups of antelopes travel more than 600 km to the lake to give birth to calves, before bringing them back to the original habitat.

"During the migration, Tibetan antelope calves may be separated from groups as they avoid attacks from predators," said Lhundrup Tsegyel, deputy head with the station.

He said patrollers rescued the eight calves and placed them in the wildlife rescue center of the station. But one of the cubs was too weak to survive.

The staff fed the baby Tibetan antelopes with milk to start with, and after their condition improves they will be taken to the grasslands and released for the next migration in July.

The center has rescued more than 400 Tibetan antelopes since it opened in 2000.

Hoh Xil reserve covers 45,000 square kilometers in China's largest area of uninhabited land, and is on the World Heritage List as a natural site.

China's antelope population declined sharply from 200,000 to 20,000 due to illegal hunting in 1980s. Currently, the population has recovered to more than 60,000.