Following Illegal Hunters That Illegally Capture the Nation's Rare Wild Birds.

The activist's vision darts across vast expanses of tall grassland, hunting for signs of life in the early morning gloom.

He speaks in a muted voice as we try to find a spot to hide in the fields. In the distance, the vast metropolis of Beijing remains asleep. During the vigil, the only sound is the quiet of the morning.

Suddenly, as the sky starts to lighten before dawn, we hear footsteps. The hunters have arrived.

Snared

In the skies above us, a multitude of winged travelers, many so small that they can fit in the palm of your hand, are migrating south for winter.

They have benefited from the extended daylight in Siberia, or Mongolia, feasting on insects and fruit. As the year comes to a close and cold breezes bring the initial freeze of winter, they head to more temperate climates to nest and feed.

There are more than 1,500 bird species, accounting for thirteen percent of the world's total – more than 800 of those are birds that migrate. Four of the nine major flyways they follow converge in China.

The patch of grassland being monitored, on the edges of the Chinese capital, is an oasis for small birds – farther in and the city skies offer few options to rest among forests of concrete.

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

The trap we stumbled upon was stretched across half the length of the field and held up with bamboo poles. In the middle, a meadow pipit was struggling frantically to escape, but the more it struggled, the more its claws became tangled.

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

Tracking the Trappers

The conservationist, in his thirties, does this work for free using his own savings. He has sacrificed many sleeping hours to rescue birds, and he has spent the last 10 years convincing the police in Beijing to enforce the law.

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

So he gathered a team who were concerned and launched a group known as the Beijing Migratory Bird Squad. He held public meetings and invited the officials of the relevant authorities. These consistent and determined acts of advocacy have shown results. The police found that catching poachers also led to 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 started in childhood. He was raised in the 1990s in a very different Beijing.

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."

Rapid economic growth brought millions of rural workers to cities. This rapid urbanisation meant grasslands were seen as land for construction, not protected zones to conserve.

The change stunned Silva. The grasslands began to shrink, as did the habitats they supported.

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

This has not made for an simple journey. One of Beijing's biggest bird dealers found out he was under scrutiny by Silva and retaliated.

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

He has also seen the departure of his army of volunteers over the years. This work requires covert operations and lost sleep. Silva says few people are willing to take on the challenging and occasionally risky job.

"My life is devoted to this," he says. "I made it a project because if you want to tackle this challenge, you must commit completely. You can't do it part-time."

He says donations pays for some of the costs – over 100,000 yuan annually – but support has waned because of the economic situation.

So he has developed new ways to track the poachers.

He analyzes aerial photos to find the trails created by the poachers. He maps those against the birds' migratory routes 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.

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

While there are environmental regulations in place, Silva believes the penalties to deter the activity do not outweigh the potential profits of trapping and trading songbirds.

Keeping a caged bird was – and for some generations in China, still is – a mark of prestige. This dates back to the Qing dynasty. Nobles and elites would build ornate bamboo cages to display their birds.

This custom that persists mainly among retired men in their later years. Silva says some elderly citizens don't realise they are breaking the law, or understand that numerous 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 a little money, they have inherited the habit and custom of caging birds," he says. "The nation progressed so fast, there was little opportunity to educate people about the environment. Once people's attitudes are set, they're extremely difficult to change."

Apprehended

Along a riverside path in Beijing, a trader has several tiny enclosures with tiny twittering birds.

Another man is positioned near a nearby market holding a bird cage shrouded in a dark cloth. He informs passers-by quietly that his songbird is valuable, worth nearly 1900 yuan.

This is a glimpse of an traditional side of the city where informal vendors have created their own market.

The path by the river extends over several miles and on a sunny weekday morning, there were shoppers browsing everything from old trinkets to dentures.

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

Music was blasting from a speaker under the low trees where a troop of elderly ladies were choreographing a traditional dance. Close by several men, all in their later years, had gathered with bird cages – some had multiple in their hands. Most were concealed by black fabric.

But today there would be no transactions because the police had appeared. 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