On the Trail Illegal Hunters Illegally Trapping the Nation's Rare Singing Birds.

The activist's vision darts across vast expanses of tall grassland, looking for any movement in the early morning gloom.

He utters a muted voice as we try to find a concealed position in the fields. Behind us, the vast metropolis of Beijing remains asleep. As we wait, we hear only our own breath.

Suddenly, as the sky turns a shade lighter with the approaching day, there is the crunch of footsteps. The hunters have arrived.

Caught

Across the heavens, countless migratory birds, some tiny enough that they can fit in the cup of a hand, are journeying southward for winter.

They have taken advantage of the warmer months in northern regions, feasting on insects and fruit. As the year winds down and cold breezes bring the initial freeze of winter, they are flying to more temperate climates to nest and feed.

There are over 1500 bird species, accounting for thirteen percent of the global population – over eight hundred of those are migratory birds. Four of the nine major paths they follow converge in China.

The area of meadow where we were, on the outskirts of the Chinese capital, is an refuge for small birds – any further and the urban landscape offer scant chance to rest among clusters of concrete.

It is also an oasis for the poachers and their "fine nets", so thin you can almost miss them.

The one we nearly walked into was strung across a large section of the field and held up with bamboo poles. At its center, a tiny bird was fighting hard to untangle itself, but the more it struggled, the more its claws became tangled.

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.

Pursuing the Poachers

The conservationist, in his thirties, carries out this mission for free using his personal funds. He has given up on many nights of sleep to rescue birds, and he has spent the last 10 years urging the police in Beijing to enforce the law.

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

So he gathered a team who did care and launched a group known as the Beijing Migratory Bird Squad. He organized public meetings and invited the heads of the local police and forestry bureau. These small and persistent acts of persuasion appear to have worked. The police realized that apprehending illegal hunters also helped in identifying other kinds of illegal operations.

"It became clear our objectives became somewhat shared," Silva says, while pointing out that enforcement is still patchy.

This fascination with birds began during childhood. He was raised in the 1990s in a distinct era for the city.

He recalls wandering in the grasslands on the city's edges where he discovered birds, frogs and snakes. "However, beginning in the 2000s, the transformation was dramatic."

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 preserve.

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

"I decided back then to dedicate myself to preservation and I chose this direction," 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 accomplices who surrounded me and beat me up," Silva remembers. He says he reported to the police but the perpetrators were not brought to justice.

He has also lost his team of helpers over the years. This work demands patience and night vigils. Silva says not many are prepared for the difficult – and sometimes dangerous job.

"My life is devoted to this," 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 donations have dipped because of the slowing economy.

So he has adopted new ways to hunt the hunters.

He analyzes satellite imagery to find the trails created by the poachers. He charts these against the birds' migratory routes and looks for areas where they may stop for the night. The aerial views can even show netting setups which can catch hundreds of small birds at night.

"Certain prized species sell for a premium," Silva says. "In big cities like Beijing and Tianjin, those who want to keep birds are now often affluent."

Although there are wildlife laws in place, Silva reckons the penalties to deter the activity do not outweigh 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 originates from the imperial era. Nobles and elites would build elaborate bamboo cages for their birds.

It's a tradition that continues mainly among retired men in their 60s or 70s. Silva says older Chinese people don't realise they are committing a wildlife crime, or grasp that so many more birds had to die in a trap so they could buy a caged bird.

"These individuals didn't even have enough to eat in their youth. Now with some disposable income, they have inherited the practice of caging birds," he says. "China developed so fast, there was little opportunity to raise awareness about the environment. Once people's attitudes are set, they're really hard to change."

Busted

On a long low wall in Beijing, a trader has several small cages with chirping songbirds.

Another man is positioned near a local 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 is a glimpse of an traditional side of the city where small unofficial traders have created their own market.

The path by the river stretches for several miles and on a typical day, there were shoppers browsing everything from old trinkets to dentures.

Information suggested that wild songbirds 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 troop of elderly ladies were performing a traditional dance. Nearby several men, all in their later years, had congregated with bird cages – some had two or three in their hands. Most were covered in black fabric.

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