IN an urban sprawl the size of Shanghai, tracking wildlife mainly means tracking birds.

It’s a major undertaking carried out by wildlife conservation stations and experienced volunteers.

Bird surveys are about more than just numbers. Conservation staff and volunteers also monitor other changes that occur year by year. Assigning the same people to the same locations is important in developing expertise on particular species.

“We aren’t so much interested in whether we count 100,000 or 100,001 birds, but rather, we want to look at how bird populations and species allocation have changed over the years,” said Bo Shunqi, engineer at the Shanghai Wildlife Conservation Management Station.

Take the sparrow, for example. It’s a common ­— many might say boring — bird in the city. A species so unremarkable that the birds don’t merit much public attention.

Surveys show that the proportion of sparrows in the bird population of city parks has decreased in recent years, while the number of the light-vented bulbul has increased. One possible explanation is the addition of more camphor and fruit-bearing trees, which are favored by the bulbuls as a food source and nesting place.

Data like this help landscape architects in urban planning projects.

Tracking wild birds is also crucial in the battle against bird flu and in compiling photos, videos and recordings for public education.

This week, we talked with two wildlife survey experts from the Shanghai Wildlife Conservation Management Station to discuss the importance of fieldwork and conservation.

Yuan Xiao

51, deputy director of the Shanghai Wildlife Conservation Management Station

After graduating from Shanghai Normal University with a degree in biology in 1988, Yuan joined Chongming County Forestry Station and Bird Banding Station, where he worked on a bird resources project on the island.

“When I first started, I was in the field for about half a year in eastern Chongming,” said Yuan. “In autumn, we captured birds, weighed them and then gave them rings before releasing them back to the wild.”

Bird surveys required going onto mud flats before sunrise and then back in the afternoon to observe wildlife between tides. Yuan said he had to wear thick waterproof pants, which caused profuse sweating even in winter.

In 2001, Yuan was assigned to the team preparing the establishment of the Chongming Dongtan Nature Reserve.

“We started giving birds color flags in 2003,” he said. “I remember we caught a curlew sandpiper in late April, and the next year, we caught him again on the exact same day. Birds have strong memories and they always return to the same location.”

In 2004, Yuan was assigned to work at the Shanghai Wildlife Conservation Management Station. Routine bird surveys along coastal areas were set up to provide more consistent data collection than in the past.

Yuan was responsible for five locations: Chongming Dongtan, the Jiuduansha wetland, Pudong, Nanhui and Fengxian. That required nine trips to each in the spring and autumn every year. The number of trips was increased when Yuan concluded they weren’t comprehensive enough.

“When the migratory birds pass through in spring and autumn, the population changes very quickly,” he said. “So in April, May, August and September, I did the surveys twice a month.”

Nowadays, 14 locations for waterbirds and 20 for land birds are monitored. Conservation staff are assisted by volunteers from the Wild Bird Society of Shanghai.

In 2006, Yuan did a bird survey in downtown Shanghai parks, covering 18 locations.

“I didn’t want it to stop with one survey, so I picked four parks for long-term observation,” he said, noting Century Park, Gongqing Forest Park, Shanghai Botanical Garden and Daning Lingshi Park.

Later, suburban parks, including Liu Island, Tianma Mountain and Sheshan Mountain, were added.

Yuan’s active fieldwork has been curtailed because of current duties at the station office. One project he is working on now is a compilation of shorebird survey data dating back to 2005. The effort involves analysis of the data by university professors.

Bo Shunqi

32, senior staff member at the Shanghai Wildlife Conservation Management Station

Bo Shunqi is the go-to person when it comes to tracking wildlife in Shanghai. He completed graduate studies in ornithology at East China Normal University in 2011.

“I have loved animals since I was a child,” he said. “I once had a small ‘zoo’ at my home with basically all the animals I could find. It was logical in choosing university studies that I settled on bioscience. It was actually an education major, but I didn’t seek to become a teacher. The curriculum was very broad, and I had many disciplines to choose from.”

Bo chose a macroscopic study of animals for his undergraduate work and a focus on avian ecology in graduate school. His main research was on the long-tailed shrike.

He spent some time in Guangdong Province, where a research base proved ideal to study this species. His room at the management station in a nature reserve there had only three furnishings: a bed, a desk and a chair.

“Being in a new place was a novelty at first, followed by lonely feelings,” he said. “My daily routine was to go out, find birds and record their songs.”

Recording birdsongs requires a close understanding of their behavior. Birds are more vocal in breeding season but go quite mum in the winter. Bo had to find new ways to set up recording devices in places where birds congregated.

In the second year of graduate school, Bo conducted an experiment to delve deeper into the songs of the long-tailed shrike. He had village children climb trees to gather nests of baby birds, then hand-raised them with meat, insects and egg yolk powder. He played various birdcalls to the nestlings to see if they could learn them.

In Haifeng County, where he stayed, there were about 150 species of birds. He found that the young long-tailed shrikes could learn songs about more than 90 birds if they fell within their vocal range.

He undertook many field trips, like visiting an islet breeding ground of terns to tag the nestlings for future tracking. To get there, he used a piece of floating wood riding the tide.

“I wasn’t thinking about how dangerous it was for myself,” he said. “I was only concerned about protecting my equipment.”

While in Guangdong, Bo traveled throughout the province, from the islands in the east to the mountains along the western border with Guangxi Province. It gave him the chance to observe wildlife and ecology in different environments.

He also observed the difficulties of wildlife conservation in Zhanjiang.

“Almost every piece of farmland was covered with tall bird netting with bells attached,” he said. “Every night, someone would gather the captured birds. Some bird parts, like turtledove eyes, were used as bait. In the market the next morning, many birds were on sale, despite public banners proclaiming that it is against the law to kill wild birds.”

Since 2011, Bo has spent an average 60 days in the field every year, covering Chongming Island, Hengsha Island and other locations for bird surveys.

“It’s not an arduous task,” he said. “Every trip in the field is more or less fruitful. It’s worthwhile even in the energy-sapping heat of August.”

Over the years, Shanghai has seen an increase in the number of magpies in the city.

In the past, they used to gather in the northern parts of Shanghai, but now they can sometimes be seen downtown. They often build nests on electric towers or in landscape trees.

Hengsha Island, where tidelands are being fenced off to create farmland, changes to bird populations hark back to the experience of Nanhui about 14 years ago.

“We are hoping to learn about the changes in bird population when there’s increased human intervention,” Bo said.