Ankur Desai

Eventually, we hear footsteps.

He's there, he's there, he's there.

Go, go, go, he's there.

Yeah, yeah, he's there.

Careful, careful.

Silva, who's in his 30s, fit and slim, chases the poacher for around two kilometres before calling the police.

He tells them not to move and searches him.

He finds dozens of videos of small birds on the poacher's phone.

They would sell for hundreds of dollars, more than many farmers make in a month.

China is home to more than 1,500 different bird species, about 13% of the global total.

And although there are wildlife laws in place, Silva told us the fines to punish poachers do not outweigh the financial benefits of catching and selling the birds.

He believes many of the poachers and buyers don't even understand why this is a crime.

On a long low wall alongside the Liangshui River in Beijing, a trader in an old military-style uniform sucks on his long wooden pipe.

He has several small cages with tiny birds twittering away inside.

Keeping beautiful songbirds is a tradition dating back centuries in China, a symbol of elegance and wealth that some older households still cling to.

But as dealers try to sell the birds in a nearby park, the police turn up.

It's part of a country-wide crackdown on wildlife crime.

Silva is encouraged, but he hopes for a more sweeping, generational change in China.

I just love them.

I want to protect them.