A hydropower plant in Yunnan province has changed its water discharge plan to protect the breeding habitat of river terns, a protected bird in China.

The Hulukou hydropower plant on the Dayingjiang River, an upstream tributary of Myanmar's Irrawaddy River, planned to discharge water from March 26 to April 1 for maintenance reasons.

Four days before it began the discharge, nature photographer Cun Zhiyong became worried. The discharge was estimated at 3 million cubic meters, which would substantially raise downstream water levels.

"This means that the breeding habitat of river terns might be flooded," said the 58-year-old.

The river tern, mainly found along rivers in India, Myanmar and Thailand, has seen drastic population declines in Southeast Asia. Listed as a Grade 2 species under the State protection, the birds mainly breed along the Dayingjiang River in Yingjiang county, Yunnan province, on the China-Myanmar border.

In 2014, 13 river terns were spotted in Yingjiang, but only five were observed last year. Last month, an investigative team sent by the local government and Kadoorie Conservation China recorded seven birds and found a breeding nest.

"River terns have beautiful postures, and they fly pretty fast. When I started bird photography, I improved my skills by following and taking pictures of the river terns," Cun said.

The terns breed from March to May every year and often nest on bare rocks or sandbanks in rivers. A sudden rise in river water levels or other disturbances, including harvesting of eggs or destruction of nests by humans or farm animals, threaten its ability to reproduce. "It will be a great loss if its population continues to decline," said Cun, who shared the warning in a WeChat group with government officials, bird photographers and conservation volunteers.

His message caught the attention of Yang Zhenghua, deputy director of the Bureau of Forestry and Grassland of Dehong Dai and Jingpo autonomous prefecture, which administers Yingjiang. Yang then arranged for officials to contact the Hulukou hydropower plant, and he personally followed the issue.

Nature reserve workers were sent to monitor the water level around three birds' nests and kept people and domestic animals away from the nests, said Zuo Changsheng, deputy director of the Yingjiang suboffice of the Tongbiguan Nature Reserve.

They also changed the water release plan to make sure that the water level stayed below the nests and that breeding was undisturbed, Zuo said on April 1.

The change of plan led to water accumulating at the front of the dam, which damaged the gate. "It will cost us at least 50,000 yuan ($7,400) to repair the gate, but we want to take the necessary actions to protect the rare birds," said Dong Jun, general manager of the plant.

The hydropower plant generates around 90 megawatts of electricity every year.

Xinhua