For a comprehensive bird survey in an area nearly twice the size of Beijing, a team of eight is "certainly not enough", according to Chen De, an associate professor from Beijing Normal University.

The professor led an eight-strong team to conduct a bird survey in Metog county, Xizang autonomous region, last month.

"I had to find as many versatile helpers as possible to maximize our efficiency," he said.

Guo Dongsheng, 61, was the most senior member of the team. Having retired just a year earlier from his position as a biology professor at Beijing Normal University, he actually taught Chen, three of Chen's students and doctor Que Pinjia, who was the technical adviser on the team, when they were students at the university.

It wasn't the first time the retired teacher had been invited to help his former students with field research.

"I love staying in the wildness,"Guo said."These jobs suit me."

In Metog, he was part of the team responsible for bird counting while on the road. He also helped Chen and his three students, who formed another group of the survey, visit some of the mist net sites they had set up to catch birds for measurements and blood samples once or twice a day during the survey.

"We typically visit four mist net sites four times a day," Chen explained. "The distance between any two sites is often more than 10 kilometers. If a large number of birds, for example 20 or more, are trapped at a net site, we need a lot of time to release them. Then we might be running late on our schedule. So we send the satellite positioning information of a site to another team and see whether they can help us tour the site along their survey route. They usually could."

For Guo, releasing birds from the entanglement on the nets is easier than finding birds in forest canopies. "The only problem is my eyes become a little blurry because of farsightedness," he said. "It gets worse especially in the darkness. So it takes me more time to release a bird from the net."

Fortunately, he had helpers, too. Huang Ke, a freelance surveyor from Chengdu, Sichuan province, assisted Guo with his net site visits in the first week of the survey. After Que joined, he visited the sites with Guo.

Huang is another Renaissance man in the group.

According to Que, who has hired Huang for a few projects over the years, Huang can work not only on bird surveys, but also on surveys of plants, mammals or even reptiles. Known for his sharp eyes and energy in the wild, he is called "Master Huang" by his teammates.

Upon Que giving him a thermal scope, Huang became his group's "man of discovery".

Sitting in the backseat of the car, he scanned forests along the roads using the device. Every day from 8 am to 9 pm, he hardly lost his focus and was always searching for something.

"Our days in the field are long and exhausting," Que said."Sometimes we get drowsy and lose our focus. But we have Huang. He is always on the watch."

When the ever-vigilant Huang would call out "stop", the car pulled over. There was usually something, out there in the tree canopy, such as a family of macaques sitting in the branches, a flock of takins standing on a sheer rocky slope or even a black bear napping on a treetop.

At the end of the survey, the team met a group of conservationists who were making a wildlife inspection in Metog. After learning what the team sighted during the survey, they asked Que whether they could borrow one of his secret weapons — a thermal scope. So Que left one for them.

"Do you want to go with them and continue staying in Metog?"Que asked Huang."If you want, I can tell them that our secret weapon is actually not the equipment, but you."