Authorities are working to overcome the effects of urbanization and help nature flourish. Xin Wen reports.

Early one morning in May 2011 at Beijing Olympic Forest Park, Zhang Yu turned his camera away from a flock of birds and watched as a hedgehog approached. It was the first time he had seen a hedgehog in the city.

The animal's cute gait and innocent features captured Zhang's heart immediately and he quickly took a photo of the fist-sized creature. Afterward, he began observing hedgehogs and tracking them down at night.

"In the following five years, I spent more than 100 nights in the park with a flashlight, searching for traces of hedgehogs, especially during summer and autumn. It's unquestionably the most lovable wild animal I have ever seen," said the 40-year-old illustrator at a magazine in Beijing that provides younger readers with information about nature and geography.

Untended land provides a perfect habitat for hedgehogs, and they usually rest and sleep on the edges of lawns, said Zhang, who has captured eight species of wild animal on photo or video in his 12 years in the capital.

"It's hard to imagine that animals live so close to the 21 million inhabitants of this bustling metropolis," he said.

According to the Beijing Gardening and Greening Bureau, at the end of 2017, the city was home to more than 600 species of wild animal. They are scattered across eight suburban areas, with large numbers living in the downtown.

From the beginning of 2016 to the start of this year, the Beijing Wildlife Rescue and Rehabilitation Center, a government-funded organization established in 2001 to care for injured wild animals, treated 1,632 creatures from 137 species.

However, that number is dwarfed by previous totals. For example, from mid-2001 to the start of 2016, the center dealt with 35,486 wild animals from 11 species.

While birds accounted for the majority, the center also helped mammals, amphibians and reptiles.

Shi Yang, senior engineer and director of the center's wildlife rescue department, said Beijing's environment provides a range of habitats for wild animals.

"The city has great biodiversity. If we draw a circle that has Tian'anmen Square at the center, we have mountains, rivers and deserts within a 100-kilometer radius," he said.

Liu Yang, an associate professor with the School of Life Sciences at Sun Yat-sen University, Guangdong province, said large numbers of birds visit Beijing during their annual migrations.

"Many mountains in north and west Beijing provide great places for them to relocate to," he said, adding that wetlands and lakes offer wild ducks and other waterfowl suitable environments to rest, while former royal parks and ancient imperial buildings provide perfect habitats for other wild animals.

When he was growing up in Beijing, Liu loved the city's biodiversity. "When I was young, I could walk to the wilderness in less than 10 minutes and see lots of birds, insects and other creatures," he said.

Avian diversity

The Beijing Swift is a symbol of the capital's avian diversity, and a regular inhabitant of palaces, temples and ancient towers. A subspecies of the common swift, the bird-the only one in the world named for Beijing-was first recorded by British naturalist Robert Swinhoe in 1870.

Every April, it flies to Beijing to breed, before moving on to southern Africa in early August. It can cover up to 200 km per hour.

The bird has four short, forward-facing claws, and once they land, the chicks find it hard to get airborne again. On the ground, the bird is ungainly and slow, and it has to rest on walls so it can become airborne quickly.

"Therefore, it stays in the nest during the breeding season, and then flies almost all of its life," Liu said

The bird has breeding points scattered across the capital. In 2008, it could be found in nearly 40 spots, while last year, it appeared in more than 100 locations.

"That's because wild animals change their living habits according to different urban architecture and city development," Liu said, noting that some common swifts have been observed taking soil from plant pots, rather than using ground soil to build nests.

Changing habits

Many wild animals alter their habits to survive in the hazardous, ever-changing urban world.

According to a study by Stan Gehrt, a wildlife ecologist at Ohio State University in the United States, some coyotes in suburban Chicago stay within the city's boundaries to avoid hunters and trappers.

As such, Chicago is a major refuge for the animals, which have learned to cross roads and avoid traffic, based on speed and volume, the study shows.

That knowledge has led some scientists to propose that volatile environments such as cities may accelerate the evolutionary process to make a species smarter, meaning many urban animals can survive better than those in the wild.

'Dead hedges'

Beijing has sought new ways of helping wild animals and humans coexist more comfortably.

This year, to promote animal and insect life, the Beijing Gardening and Greening Bureau plans to plant at least one Benjeshecken, aka a "dead hedge", in all the city's parks.

Dead hedges are made from materials left over from pruning, clearing or forestry activities. A ditch 4 meters long and 6 m wide is dug and filled with soil, stones and leaves. Native plants and the excess materials are then added to form an artificial barrier, which gradually becomes a beetle bank, providing food and shelter for small mammals and reptiles.

Shi, from the rescue and rehabilitation center, said he has shown the city authorities low-density, medium-sized bushes, and suggested gradually replacing the flat, mown grassland in parks with them.

Meanwhile, some NGOs have explored new measures to alter the city's environment. For the past two years, the Shan Shui Conservation Center, a nature protection organization, has monitored the varieties and numbers of butterflies in the Beijing Botanical Garden and Badaling National Forest Park.

Tan Lingdi, a project officer with the center, said butterflies are good indicators of ecological health because they are particularly sensitive to environmental changes.

"When there are many species of butterflies in one place, it indicates that the environment is pretty good and plant life is diverse," she said, adding that the center hopes to cultivate more food stocks for the butterflies so their numbers will rise.

Terry Townshend, founder of the Birding Beijing website, suggested establishing artificial nesting boxes across the city and engaging more schools and real estate companies in the construction process. Hundreds of boxes have been made and will soon be installed across the capital.

The British national, a common swift enthusiast, has also proposed building a "wild ring road" to connect several areas of wilderness in Shunyi district to provide a place for birds to rest during their spring and autumn migrations.

Urbanization

Despite the positive moves, the rapid progress of urbanization has seen suitable wild animal habitats shrink in large cities.

Liu, the professor, recalled that his middle school in Beijing's Haidian district was surrounded by paddy fields containing plants that provided habitats for birds and insects, and deer appeared occasionally.

In recent years, though, he has noticed a decline in food sources for wild birds, while the expansion of high-rise buildings and concrete yards has led to a lack of the soil many birds use to build nests.

"For example, many birds will not build nests in certain areas if they can't find food and territory, so they may not even come to the city anymore," he said, adding that the development of artificial lawns and greenery has also affected the lives of wild birds.

"We trim lawns and spray pesticides frequently to keep the city landscape in good condition, but we forget that wild animals may be affected."

Shi said that his wildlife rescue center treats a range of injured animals every season. In spring and autumn, migratory birds are the main focus of attention.

In early May, Eurasian woodcocks were frequently seen above Beijing. When flying to Northeast China to breed, they pass through the downtown and are easily distracted by the images of blue skies and white clouds reflected by the glass walls of high-rise buildings.

"They are likely to hit the glass curtain wall. If a bird is just knocked unconscious, we let it rest for a while. But these birds fly at high speed, so many die as a result of collisions," Shi said.

Some species, such as swallows, magpies and common kestrels, like to nest in the spaces between air conditioners and walls, and chicks sometimes fall from high nests and starve to death as a result.

Height is not the only problem, though. "If people don't notice the nests under air-conditioner ventilation pipes in time, the chicks may roast to death as a result of the high temperatures the machines produce," Shi said.

Moreover, the city is full of predators, especially cats, which hunt birds, insects and small mammals.

A 2013 study by the Smithsonian Conservation Biology Institute in the US showed that cats, either feral or pets, kill 1.4 billion to 3.7 billion birds in the US every year.

The study added that felines also kill about 20.7 billion mammals in the US annually.

Future plans

In a bid to promote protection, Zhang Yu, the hedgehog enthusiast, has plans to publish a book of the wild animals he has photographed in Beijing.

"Not only hedgehogs, but all the wild creatures I have watched in the city make me feel that I am not living in a metropolis but a wild field," he said. "I like to make friends with them, even those in my community yard, and it makes me happy every time I see those cute creatures."