Tracking Illegal Hunters That Illegally Capture China's Protected Wild Birds.

The activist's eyes scan over miles of tall grassland, looking for signs of life in the inky blackness.

He speaks in less than a whisper as they attempt to locate a place of cover in the fields. Behind us, the sprawling city of Beijing has yet to wake. During the vigil, the only sound is the quiet of the morning.

Suddenly, as the sky turns a shade lighter with the approaching day, the sound of footsteps emerges. The poachers are here.

Caught

Overhead, a multitude of winged travelers, some tiny enough that they could rest in the cup of a hand, are traveling to the south for winter.

They have benefited from the warmer months in Siberia, or Mongolia, consuming insects and fruit. As the year winds down and icy winds bring the first frosts of winter, they journey to more temperate climates to nest and feed.

China is home to 1500-plus bird species, representing roughly 13% of the planet's species – over eight hundred of those are migratory birds. Four of the nine major migration routes they follow converge in China.

This particular field being monitored, on the edges of the Chinese capital, is an refuge for small birds – farther in and the city skies offer little opportunity to rest among clusters of concrete.

It is equally attractive for the poachers and their "fine nets", so fine you can almost miss them.

A net we almost encountered was extending over a large section of the field and held up with bamboo poles. In the middle, a tiny bird was fighting hard to escape, but the more it moved, the more its claws became tangled.

It was a protected songbird, a species under protection in China, and an important "bio-indicator" – which signifies if its numbers are thriving, so is its habitat.

Hunting the Hunters

Silva, who is in his 30s, does this work for free using his personal funds. He has forgone many nights of sleep to set songbirds free, and he has spent the last decade persuading the police in Beijing to enforce the law.

"Back in 2015, there was little interest," he states.

So he recruited volunteers who did care and established a group known as the Bird Protection Unit. He held public meetings and invited the heads of the local police and forestry bureau. These small and persistent acts of persuasion seem to have paid off. The police found that catching poachers also led to identifying other kinds of criminal activity.

"It became clear our goals were partially aligned," Silva says, while pointing out that enforcement is still patchy.

His passion for avian life started in childhood. He was raised in the nineties in a much changed capital.

He remembers exploring the grasslands on the city's edges where he found birds, frogs and snakes. "However, beginning in the 2000s, everything changed."

China's booming economy brought a huge influx of rural workers to cities. This expansion meant grasslands were seen as areas for development, not sanctuaries to preserve.

The change stunned Silva. The grasslands started disappearing, as did the ecosystems they sustained.

"I made the choice back then to pursue environmental protection and I took this path," he says.

This has not made for an easy life. A major Beijing's biggest bird dealers found out he was under scrutiny by Silva and retaliated.

"He assembled several of his associates who surrounded me and assaulted me," Silva remembers. He says he went to the police but the perpetrators were not brought to justice.

He has also seen the departure of his team of helpers over the years. This work demands stealth and sleepless nights. Silva says few people are willing to take on the challenging and occasionally risky job.

"I do this full-time," he says. "I treat it as a mission because if you want to solve this big problem, you must give it your all. You can't do it part-time."

He says fundraising pays for some of the costs – more than 100,000 yuan a year – but support has waned because of the slowing economy.

So he has adopted new ways to track the poachers.

He studies aerial photos to find the routes worn away by the poachers. He charts these against the birds' flight paths and looks for areas where they may stop for the night. The satellite images can even show lines of net traps which can capture hundreds of small birds during darkness.

"Siberian rubythroats and bluethroats sell for a high price," Silva says. "In urban centers like Beijing and Tianjin, those who want to keep birds are now often affluent."

Although there are environmental regulations in place, Silva reckons the penalties to punish the crime do not exceed the financial benefits of trapping and trading songbirds.

Keeping a caged bird was – and for some generations in China, still is – a status symbol. This dates back to the imperial era. Nobles and elites would build elaborate bamboo cages for their birds.

It's a tradition that persists mainly among older individuals in their 60s or 70s. Silva says older Chinese people don't realise they are breaking the law, or grasp that so many more birds had to die in a trap so they could buy a pet.

"This generation didn't even have enough to eat in their youth. Now with some disposable income, they have adopted the practice of keeping birds in cages," he says. "China developed so fast, there was little opportunity to educate people about ecology. Once people's attitudes are formed, they're really hard to change."

Busted

Along a riverside path in Beijing, a vendor has several tiny enclosures with chirping songbirds.

Another man is positioned near a local market holding a bird cage covered by a black veil. He tells passers-by quietly that his songbird is rare, worth about 1900 yuan.

This offers a view of an old Beijing where small unofficial traders have created their own market.

The area alongside the water extends over several miles and on a typical day, there were people looking at everything from vintage jewellery to dentures.

We were told that protected birds could be bought in a small park. The location was not concealed.

Music was blasting from a speaker in a shaded area where a group of elderly ladies were performing a traditional dance. Close by several men, all in their later years, had gathered with bird cages – some had two or three in their hands. Most were covered in black fabric.

But on this occasion there would be no sales because the police had appeared. They were questioning the bird owners and recording details. Defiant, one man claimed he was {taking his caged bird for a walk|simply exercising his