A pair of great hornbills were captured mating in the wild in southwest China's Yunnan Province, a rarely-seen scene considered to be a signal of the improving local environment.

In late February, photographer Yan Xiao took the video in the county of Yingjiang in Dehong Dai and Jingpo Autonomous Prefecture that borders Myanmar.

"I know that great hornbills come back to the same nest for breeding, so I've been coming here to wait for such an opportunity every year since 2015. I'm really lucky this time! " Yan told CGTN, noting that he waited for four days before capturing the moment.

Hornbills are rare in China. They have been listed as one of the country's key protected animals.

Dehong Dai and Jingpo Autonomous Prefecture is one of the major habitats for the rare birds. It's the only place in China where all the five species can be found. It's estimated that there are about 20 to 30 great hornbills here. 

The number of hornbills has grown in the area with the aid of environmental protection efforts.

"The first time I came here in 2015, I only saw five hornbills. To my surprise, I saw a total of 42 one day this year," said Yan. 

The small county is now a popular destination for bird lovers from both home and abroad. Bird watching has become an important industry for the local tourism industry.

Experts say hornbills shoulder high risks in reproduction. 

"During the brooding period, the female hornbills stay in the tree hole all the while to look after the babies, and the males are responsible for foraging outside. Once the males come to a bad end, the females and the babies would starve to death," said Yang Zhenghua, director of the Tongbiguan National Nature Reserve in Yunnan Province.

(Cover photo: Two great hornbills are captured feeding each other. / Courtesy of Yan Xiao)

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