During the autumn season in Dandong City, Liaoning Province, the Yalu River estuary welcomes innumerable migratory birds. On the mudflats, migratory birds either rest or forage. As the tide surges, flocks of birds rise and fall with it, creating spectacular “bird waves”. Climbing up the watchtower of Gushan Reed Fields and looking into the distance, one can see the wetlands glisten with stretches of light and shadow under the sunlight, while the birds hover in the sky, emitting a burst of chirping.