At the Yalu River estuary bordering the Yellow Sea, tens of thousands of migrating birds fly over each spring to rest, find food and breed. The massive reserve, called the Dandong Yalu River Estuary Wetlands, is located in Xincheng district in Donggang in Dandong in Liaoning province.

The massive reserve covers an area 108,057 hectares in size. The Yalu River and ocean feed clear water to an area that is home to 344 species of plants, 240 types of birds, 88 varieties of fish, and amphibians and mammals. Dense reed swamps provide shelters and breeding grounds for birds.

Each year, eight varieties of birds protected under the National Grade One Protection law migrate and inhabit here, including red-crowned cranes, napped cranes, white cranes and white storks. The nature reserve is home to 29 birds protected under the National Grade Two Protection law, including whooper swans, white forehead wild geese and small ladle snipes.

Endangered birds that stop here during their annual migration include Saunders's gulls and spot-backed great reed warblers. Of the array of birds found here during certain times of the year, 114 are species covered by the Sino-Japanese Migrant Bird Protection Agreement and 43 species are covered by the Sino-Australian Migrant Bird Protection Agreement. The nature reserve provides a last stop for birds that fly to China from Australia and New Zealand before continuing on to their breeding grounds in far eastern Russia and the US state of Alaska. Scholars wanting to watch the rare birds are among the annual visitors.