The Yellow River Delta National Nature Reserve, despite the cold wave on December, received a flock of “old friends”. As an important transit point for bird migration, thousands of migratory birds, including red-crowned cranes, travel thousands of miles to winter here every year.

The red-crown crane, known as a symbol of luck and longevity, is class-A protected bird with a global wild population of about 2,500. Zhalong, the route from Heilongjiang to the Yellow River Estuary to Yancheng, Jiangsu is an important migration route for rare birds such as red-crowned cranes. Every winter, there is always a large community of red-crowned cranes migrate to the Yellow River Estuary, and some may stay here for a nice and easy winter.

The Yellow River Delta National Nature Reserve is the northernmost overwintering boundary of red-crowned cranes in China, and the annual migration number has increased from more than 70 at the beginning of the reserve to more than 350 now.

The Yellow River Delta National Nature Reserve has been rated as one of the "six most beautiful wetlands" in China in recent years.