An oriental white stork is just a rare bird in most people's eyes, but for Zhao Zhichun, Katyusha is one of his closest friends.

People often see the stork flying over Khanka Lake to a research station on the shore, where she awaits the appearance of Zhao.

Zhao, 43, a native of Jilin province, is an expert in wetland monitoring at the Chinese Academy of Sciences' Khanka Lake research station in Heilongjiang province.