Desert oasis a lifeline for migratory birds

For nearly three months, a young black stork stayed in its nest on a cliff in Gansu province, waiting to learn how to fly. Then the time came for the nestling to leave its temporary home in Gaotai county, Zhangye.

Other chicks in the same nest had already flown off. But the third, whose leg had been broken, remained behind.

Documentary filmmaker Zhao Hai remembered the scene while watching footage captured by an infrared camera near the nest.

The young bird hesitated to leave the nest, while its parents stayed nearby. Eventually, the chick took off. Its parents flew alongside it for a while, as if encouraging it on its first flight.

For Zhao, who has observed birds for about 30 years and filmed them for more than two decades, it was one of many moments that have made black storks more than a subject for his camera. "When we watch birds, sometimes their behavior is basically the same as that of humans," he said.

He recalled another touching scene. When newly hatched black stork chicks were still tiny and April mornings and evenings could be cold, an adult bird brought pieces of plastic to the nest and covered the chicks with them.

"It was almost like covering the chicks with a blanket to keep them warm," Zhao said.

Such moments are difficult to capture. Black storks are highly wary of people, and Zhao has tried to minimize disturbing them while filming.

So far, he has filmed two nests through most of the breeding process. But what he has seen at the nests is part of a much larger story unfolding along the Zhangye Heihe Wetland.