On the Trail Illegal Hunters Who Illegally Snare China's Rare Songbirds.

The conservationist's vision darts over miles of tall grassland, looking for suspicious activity in the early morning gloom.

He speaks in less than a whisper as we try to find a place of cover in the fields. In the distance, the vast metropolis of Beijing remains asleep. During the vigil, we hear only the quiet of the morning.

And then, as the sky turns a shade lighter before dawn, there is the crunch of footsteps. The hunters have arrived.

Trapped

Overhead, countless migratory birds, many so small that they could rest in the cup of a hand, are journeying southward for winter.

They have taken advantage of the long summer days in Siberia, or Mongolia, feasting on insects and fruit. As the year winds down and cold breezes bring the first frosts of winter, they journey to warmer places to find food and shelter.

China is home to more than 1,500 bird species, representing roughly 13% of the global population – more than 800 of those are migratory birds. Several of the major paths they follow intersect in China.

This particular field where we were, on the outskirts of the Chinese capital, is an haven for small birds – any further and the urban landscape offer little opportunity to rest among forests of concrete.

It is equally attractive for the poachers and their "mist nets", so fine you can barely see them.

The trap we stumbled upon was extending over half the length of the field and supported with bamboo poles. At its center, a small finch was struggling frantically to free his legs, but the more it struggled, the more its feet got ensnared.

This was a protected songbird, a protected bird in China, and an important "indicator species" – meaning if its numbers are thriving, so is its environment.

Pursuing the Poachers

Silva, who is in his 30s, carries out this mission for free using his own savings. He has sacrificed many sleeping hours to set songbirds free, and he has spent the last decade persuading the police in Beijing to prioritize this issue.

"In the early days, there was little interest," he states.

So he enlisted helpers who did care and established a group known as the Bird Protection Unit. He held public meetings and brought in the officials of the local police and forestry bureau. These consistent and determined acts of persuasion seem to have paid off. The police discovered that catching poachers also led to identifying other kinds of criminal activity.

"We found our objectives became somewhat shared," Silva says, adding the caveat that implementation remains inconsistent.

This fascination with birds started in childhood. He grew up in the nineties in a much changed capital.

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

China's booming economy brought millions of rural workers to cities. This rapid urbanisation meant grasslands were seen as areas for development, not conservation areas to preserve.

This shift shocked him. The grasslands receded, as did the habitats they supported.

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

It has not been an easy life. A major Beijing's biggest bird dealers discovered he was under scrutiny by Silva and fought back.

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

He has also lost his team of helpers over the years. This work requires patience and night vigils. Silva says not many are prepared for the difficult – and sometimes dangerous 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 commit completely. You cannot be half-hearted."

He says fundraising pays for some of the costs – over 100,000 yuan a year – but funding has declined because of the slowing economy.

So he has developed new ways to hunt the hunters.

He analyzes satellite imagery to find the trails 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 scores of small birds at night.

"Certain prized species command a premium," Silva says. "In big cities like Beijing and Tianjin, those who want to keep birds are now quite wealthy."

While there are wildlife laws in place, Silva reckons the fines to punish the crime do not exceed the financial benefits of catching and selling songbirds.

Owning a pet bird was – and for some people in China, still is – a mark of prestige. This originates from the imperial era. Wealthy individuals would build ornate bamboo cages for their birds.

It's a tradition that continues mainly among older individuals in their later years. Silva says some elderly citizens don't realise they are committing a wildlife crime, or understand that numerous birds had to die in a trap so they could buy a pet.

"This generation often lacked enough to eat growing up. Now with some disposable income, they have adopted the practice of caging birds," he says. "China developed so fast, there was little opportunity to educate people about the environment. Once people's attitudes are set, they're really hard to change."

Disrupted

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

A separate individual stands outside a nearby market holding a bird cage shrouded in a dark cloth. He tells passers-by discreetly that his songbird is valuable, worth about 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 typical day, there were shoppers browsing everything from vintage jewellery to dentures.

Information suggested that protected birds could be purchased in a nearby green space. It was easy to find.

Music was blasting from a speaker under the low trees where a group of elderly ladies were performing a fan dance. Nearby several men, all over 50, had congregated with bird cages – some had multiple in their hands. Most were covered in dark cloth.

But today 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