In 2019, the city launched a project to protect the bee-eaters, and Lu's institute started working to "build a good survival environment for the birds" and to improve bird monitoring.

"If the bee-eaters are thriving in a city, it means that the local wetland system is good," Lu said. "It also shows that the city pays great attention to the environment."

To enhance wetland protection, Lu's institute hired two patrollers.

One of them is Chen Chuanglin, a 40-year-old who previously worked for the agriculture and rural affairs bureau of Haikou's Xiuying district.

Years of forest patrol work honed his skills to "identify bird species by their song", he said.

"I began working for the Wuyuan River environment protection project in December 2019."

In addition to his daily patrols, Chen also helps monitor birds in other areas in Haikou.

"I learned from horticulturalists how to identify plants, and I taught myself how to install infrared cameras," he said, adding that he uses the devices to record animals and plants in his patrol areas.

"As a good patroller, you need to understand the characteristics and functions of a forest when you see it," he said. "You need to be able to tell the types and habits of birds when you see them."

Chen is now a major force in the monitoring of bee-eaters.

"After getting involved in bird protection, I realized that Mother Nature has a lot of hidden secrets," he said. "I learned that people, the trees, the birds and the natural environment are all interconnected."

Xinhua