Yu Lian, an ornithologist in Liaoning Province in Northeast China, was crawling in the dense reeds and grass. He had a striking encounter with a 1.5-meter-high Red Crowned Crane, whose beak was sandwiched on the long stem of the reed.

Without hesitation, the Crane quickly squatted down, spread its wings, and flapped its wings in an aggressive manner. Although Yu knew that the density of the crane's bones was several times that of human beings, and its swoop would easily break his ribs, his joy still overwhelmed his fear.

The obvious nesting behavior and abnormal vigilance of the Red Crowned Crane indicate that the Red Crowned Crane is engaged in breeding activities, which has never been observed in the past 14 years near the Daling River Estuary in Jinzhou City, Liaoning Province. The endangered red crowned crane is under national first-class protection. The wetland near the Daling estuary is regarded as one of the southernmost breeding places of these rare birds.

According to Yu, vice president of Jinzhou wildlife and Wetland Protection Association, environmental changes and human activities mean that since 2009, there has been no record of endangered birds breeding near the Daling estuary.

"We found that the first two birds were born on May 12 and 13 respectively," Yu said. "After two weeks, they have grown a lot and can run everywhere."

Zu Fengkun, director of the local forestry and grassland Bureau, said that the breeding process of at least four pairs of red crowned cranes had been observed, and three pairs of red crowned cranes had successfully hatched. Yu pointed out that the low fertility rate of cranes (only two eggs per nest) and the low survival rate of young birds led to slow reproduction.

Guo Yumin, a professor at Beijing Forestry University, said: "red crowned cranes are very picky about their breeding grounds. They need enough food, good biodiversity, and especially the safety of the surrounding environment."

Guo said that the reappearance of the natural breeding of red crowned cranes in this area shows that in recent years, the environment at the mouth of the Daling River has been fundamentally improved, which is suitable for the reproduction of endangered birds.

Pei Qiang, general manager of dalinghekou Wetland Park, said: "ten years ago, when we started the wetland restoration project in this area, the area suffered from salinization and coastal erosion, and almost became a barren beach with sparse vegetation.

"In contrast, the salinity of the wetland has been greatly reduced, and the area of reeds has been restored to 22 square kilometers, three times as much as before."

He added that the wetland protection process has made the region a paradise for bird breeding and wintering.

More than 10 species in the wetland park are under national first-class protection, and more than 50 species are under second-class protection, including Oriental White Stork and great bustard.

Jinzhou is located along the main bird migration corridor, so millions of wild migratory birds are welcomed every year.

From 2016 to 2020, the local authorities restored more than 2666 hectares of wetlands, bringing the number of birds found in the city to more than 370.