The wetlands in Yalu River, Dan Dong, is an important bird migratory site for the godwit and great knot. These birds migrate between New Zealand, China, North Korea and Alaska every year, with godwit’s migratory flight being the longest nonstop migration of any bird in the world. As more wetlands and coasts in South Korea and China become concretised, the wetlands in Yalu River remains one of the last sanctuaries for these birds. 

During migration season in 2019, Zhao Renhui and a local researcher named Mr Bai Qingquan visited the mouth of the Yalu River. Mr Bai has spent more than 10 years counting the birds according to a complicated system and observed that the bird numbers are dwindling every year. This year, he counted 54,231. 

The best viewing time was during high tide in the morning. Every time the tide came in, great flocks of birds flew up from the shoreline, forming huge murmurations. The spectacular sight was witnessed by huge crowds of onlookers. The murmurations, which take beautiful, ever-changing forms, demonstrate the powerful mutability of nature.