By Alex Kirby BBC News Online environment correspondent

Campaigners in Brazil believe the illegal wildlife trade is so extensive that some species may be driven close to extinction.

They say poachers are taking an estimated 38 million birds, animals and reptiles from the wild each year.

Some are caught to provide meat, or for use in traditional medicine. But most are stolen for sale to foreign collectors at huge profits.

The claims come from the Brazilian National Network against the Trafficking of Wild Animals (Renctas).

They are revealed in Rich Pickings, a film made by the Television Trust for the Environment (TVE) in its Earth Report series, and shown on BBC World.

 Click here to watch BBC World and its report on Brazil's wildlife.

TVE says the illegal wildlife trade in Brazil is an issue of law and order, poverty, and the greed of people in wealthier countries.

Little success

It is now Brazil's most profitable activity after arms and drug smuggling. Interpol says the global illegal wildlife trade is worth $6bn a year.

The smuggled boa reaches freedom

Renctas was founded three years ago by Dener Giovanini, and his work led to the establishment of Brazil's first environmental police force.

But the campaigners say the police manage to intercept just 0.5% of smuggled wildlife.

The profit on endangered species can be as high as 2,000%. Dener receives regular death threats, but he will not give up.

He says: "I am scared for myself, but most of all I am scared for everyone who works with me.

"But even if the traffickers kill me, our work will continue because we are already a network. Over 30,000 people are working together in this war. They can do what they like with me, but they'll never stop us."

Unlimited offer

The TVE crew filmed a meeting with traffickers at their hotel, using a concealed camera.

One told them: "I can get what you want - monkeys, turtles, parrots, macaws, whatever you want."

Profits are often huge

At a dealer's home they saw a parrot which would sell for $2,000 to a foreign buyer, with endangered species including marmosets, eagles and turtles.

They went to a forest with collectors who raided a parakeet's nest, intending to sell the hatchlings as baby parrots, which fetch much more.

One collector said: "We know this is illegal, but it's the only way we can make a living. It's better than buying a gun and going out there shooting and robbing people. If you do that, you end up dead."

No deterrent

A dealer in Rio de Janeiro claimed he could provide anything a collector wanted.

Conditions can be appalling

He said: "I can get you a toucan for $130. Yellow or red breasted macaws are $600. I bring in 200 turtles at a time from Bahia - I carry them in my pockets. I've lost count of the amount of police checkpoints I've gone through like this."

On a trip to the Amazon the crew posed as biologists to win the confidence of an indigenous tribe.

They saw animals and birds tightly chained, or kept in small cages, apparently destined for Brazilian cities.

In Belem, on the coast, a herbal medicine seller told them she was no longer allowed to sell any animal products, though she offered them some when they switched off their cameras.

To show how easy it is to smuggle wildlife, one Renctas agent carried a baby boa constrictor in a plastic bottle in his luggage on an internal flight, without once being searched.

TVE says the Brazilian Government wants to stop the traffickers, but will need international help if it is to succeed.