Oriental white storks are pictured at Xingkai Lake in the city of Jixi, northeastern China's Heilongjiang Province, Nov. 13, 2019. (Xinhua/Li Wenzhong)

More than 400 oriental white storks have been seen among migratory birds making a stopover at a border lake between China and Russia this year, local authorities said Tuesday.

Xingkai Lake, located in the city of Jixi, northeastern China's Heilongjiang Province, is the biggest border lake on the China-Russia border. Thousands of birds make stop-overs there for temporary stays before heading further south for winter migration.

This year, the Xingkai Lake National Nature Reserve saw the arrival of the largest population of oriental white storks.

The oriental white stork is listed as endangered by the International Union for Conservation of Nature. The wild population is estimated at less than 3,000.

Great efforts have been made in recent years to improve the eco-system in the lake area, according to Liu Huajin from the reserve.