Following Poachers Who Illegally Snare China's Rare Singing Birds.

The conservationist's eyes scan over vast expanses of open meadows, searching for signs of life in the early morning gloom.

He utters less than a whisper as the team seeks a place of cover in the grasslands. Behind us, the vast metropolis of Beijing has yet to wake. As we wait, the only sound is our own breath.

Suddenly, as the sky turns a shade lighter ahead of sunrise, there is the crunch of footsteps. Illegal trappers are present.

Caught

Across the heavens, countless migratory birds, some tiny enough that they could rest in the palm of your hand, are journeying southward for winter.

They have taken advantage of the extended daylight in northern regions, eating insects and fruit. As the year comes to a close and cold breezes bring the first frosts of winter, they head to more temperate climates to nest and feed.

The nation hosts over 1500 bird species, accounting for 13% of the world's total – over eight hundred of those are migratory birds. Four of the nine major migration routes they follow cross through China.

This particular field where we were, on the outskirts of the Chinese capital, is an refuge for small birds – any further and the city skies offer scant chance to rest among clusters of concrete.

It is also an oasis for the poachers and their "fine nets", so delicate you can barely see them.

The one we nearly walked into was strung across half the length of the field and supported with bamboo poles. In the middle, a tiny bird was fighting hard to untangle itself, but the more it moved, the more its feet got ensnared.

It was a meadow pipit, a species under protection in China, and an important "bio-indicator" – which signifies if its population is healthy, so is its habitat.

Tracking the Trappers

Silva, who is in his 30s, carries out this mission for free using his own savings. He has given up on many nights of sleep to release trapped birds, and he has spent the last 10 years convincing the police in Beijing to enforce the law.

"Initially, no-one cared," he remarks.

So he gathered a team who did care and established a group known as the Beijing Migratory Bird Squad. He held community gatherings and brought in the officials of the local police and forestry bureau. These small and persistent acts of advocacy seem to have paid off. The police realized that apprehending illegal hunters also led to tracking down other kinds of illegal operations.

"We found our goals were somewhat shared," Silva says, while pointing out that enforcement is still patchy.

Silva's love of birds began during childhood. He grew up in the 1990s in a very different Beijing.

He recalls wandering in the fields on the city's edges where he discovered birds, frogs and snakes. "But starting from the 2000s, everything changed."

China's booming economy brought a huge influx of rural workers to cities. This expansion meant grasslands were considered empty places to build, not conservation areas to conserve.

The change stunned Silva. The grasslands receded, as did the habitats they supported.

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

It has not been an simple journey. One of Beijing's biggest bird dealers discovered he was under scrutiny by Silva and fought back.

"He gathered several of his associates who confronted me and beat me up," Silva recalls. He says he went to the police but those responsible were not brought to justice.

He has also seen the departure of his team of helpers over the years. This work requires patience and night vigils. Silva says not many are willing to take on the challenging and occasionally risky job.

"This is my full-time commitment," he says. "I treat it as a mission because if you want to address this major issue, you must give it your all. You can't do it part-time."

He says fundraising covers some of the costs – over 100,000 yuan a year – but support has waned because of the slowing economy.

So he has developed new ways to hunt the hunters.

He analyzes aerial photos to find the trails worn away by the poachers. He maps those against the birds' flight paths and looks for areas where they may stop for the night. The satellite images can even show netting setups which can catch hundreds of small birds during darkness.

"Siberian rubythroats and bluethroats command a high price," Silva says. "In urban centers like Beijing and Tianjin, those who want to keep birds are now quite wealthy."

Although there are wildlife laws in place, Silva argues the fines to punish the crime do not exceed the potential profits of catching and selling songbirds.

Owning a pet bird was – and for some people in China, still is – a status symbol. This dates back to the Qing dynasty. Nobles and elites would build ornate 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 may not understand they are committing a wildlife crime, or grasp that numerous birds were killed in a trap so they could buy a pet.

"These individuals didn't even have enough to eat in their youth. Now with some disposable income, they have adopted the practice of caging birds," he says. "The nation progressed so fast, there was no time to educate people about ecology. Once adults' values are set, they're extremely difficult to change."

Busted

On a long low wall in Beijing, a trader has several tiny enclosures with tiny twittering birds.

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

This offers a view of an old Beijing where small unofficial traders have established a niche trade.

The area alongside the water stretches for several miles and on a sunny weekday morning, there were shoppers browsing everything from vintage jewellery to false teeth.

We were told that protected birds could be purchased in a small park. It was easy to find.

Loud music played 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 concealed by dark cloth.

But on this occasion there would be no sales because the police had arrived. 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