When Zhou Longshan started filming birds 10 years ago at Baiyangdian Lake,     1     major wetland in northern China, he just wanted to record his favorite species—egrets (白鹭).

Then things snowballed. In the following years, the teacher became a bird watcher, a volunteer ranger at the lake, a photographer     2    (document) over 110 bird species, and an     3     (education) popularizing bird-related knowledge among students.

“Sharing bird-protection knowledge with children can make them feel the     4    (beautiful) of their hometown and the importance of birds, and help them cultivate the habit of protecting birds from an early age,” he said.

Growing up in a local village, Zhou,60, has fond childhood memories     5    (associate) with the wetland.

“When I was a child, the water in Baiyangdian was limpid. The fish and aquatic plants in the water could be seen clearly,” he said. “I often caught fish with my friends, rowed boats and drank the lake water     6     I was thirsty.”

Between the 1960s and 1980s,     7    , Baiyangdian suffered severely from industrial pollution. Chemicals poisoned the water and lake beds, decimating the aquatic life. In the 1990s, the lake     8    (near) dried up due to climate change.

When Zhou became a teacher in the 1990s, the stink from the lake could sometimes be smelled from his village. “The lake became stinking, the population and species of fish and birds decreased, and the locals were unwilling to go near the lake,” he recalled.

Since the Xiong’an New Area was established in 2017, Baiyangdian’s rehabilitation and protection activities     9    (improve) greatly. The water quality has improved from Level Ⅴ-the     10    (low) in China’s five-tier water assessment system-to Level Ⅲ.

Zhou will retire in June. “I will continue patrolling the lake and photographing the birds, to contribute to the protection of birds in my hometown,” he said.