CURUP, INDONESIA (NYTIMES) - Hiding in the dense Sumatran jungle, the poacher chose a thin branch, coated it with home-made glue and played a snippet of birdsong on an old cellphone. Within moments, three tiny birds alighted on the branch and were trapped.

Known as ashy tailorbirds, they were destined for the Indonesian island of Java, where they were likely to spend their lives in a collector's cage.

Millions of similar birds are stolen from the wild every year, and prized specimens can ultimately sell for thousands of dollars. These birds are not treasured for their plumage or meat, but for their songs.

An illicit trade that begins in the primeval forests takes many of the birds to Indonesia's teeming capital, Jakarta, where they are entered into high-stakes singing competitions at which government officials frequently preside.

The poacher, named Mr Afrizal, gently pulled the birds from the branch, peeled the glue from their feet and placed them in a metal cage, which he covered with a faded Angry Birds T-shirt. This is how Mr Afrizal, doing his part to rob Indonesia of its wildlife, has caught more than 200,000 songbirds over the past 15 years.

"I do this work to survive," he said, setting a new trap. "Of course, I feel guilty. If they die, I feel even sadder."

Officials and conservationists say wild songbirds are disappearing at a tremendous rate across Indonesia's vast archipelago. Much of the demand is fuelled by the growing craze for bird singing contests.

Keeping caged songbirds is a centuries-old tradition among Javanese men of wealth and power. But the singing contests have become a popular phenomenon, and so, too, has owning birds. Before large gatherings were suspended in March because of the coronavirus pandemic, more than 1,000 songbird competitions were typically held each year, mainly on Java, and many drew thousands of people.

Such events are often held in the name of community leaders, police chiefs and other officials - even Indonesia's President, Mr Joko Widodo, who officiates at the annual President's Cup. But behind them lies a booming illicit business, backed by corrupt elements of the police and the military.

Especially sought after is the murai batu, known in English as a white-rumped shama, which can mimic the melodies of other songbirds. It is a species favoured by Mr Joko and many other collectors, and one that is fast disappearing from Indonesia's forests.

In 2018, Mr Joko entered his own murai batu in the President's Cup, but lost to Mr Dede Alamsyah, a car wash owner from Central Java.

The President told reporters that he'd offered to buy the winning bird, but that Mr Dede had declined to sell. Mr Dede put the bird's value at US$47,000 (S$66,800), enough to buy a large house.

Mr Marison Guciano, founder and executive director of the bird protection organisation Flight, estimates that poachers capture more than 20 million songbirds a year, primarily from Sumatra, Indonesia's third-largest island.

Captive breeding of songbirds has sprung up as a backyard industry. But catching wild birds, though usually illegal, is cheaper than breeding them. Many unscrupulous dealers, using counterfeit leg bands and forged documents, pass off wild birds as ones they have bred themselves, Mr Marison said.

"For the songbird, the smuggling is massive and open," he said. "Actually, songbird smuggling is considered to be a normal thing. The laundering process is happening right in front of our eyes."

As Sumatra's songbird population has declined, Mr Marison said, poachers have begun hunting in the forests of Malaysia and southern Thailand, particularly for the murai batu.

Indonesian law enforcement officials acknowledge that some members of the police and military are involved in the illicit trade and help smugglers transport birds.

Mr Hifzon Zawahiri, the chief of the National Wildlife Protection Office for Lampung, Sumatra's southernmost province, said his understaffed agency faced a well-organised criminal songbird syndicate.

"There is no doubt that the police, the military and officers of the forestry agency itself - the forest police - are involved," he said.

In late January, thousands of bird aficionados, almost all of them men, flocked to a park for the South Jakarta Police Chief's Cup.

Sixty individual contests, organised by species and level of competitiveness, were held in two open-sided pavilions. Up to 77 birds were entered in each event. The top prize was US$715.

These competitions bear little resemblance to hearing birdsong in the forest. It is more like attending a boxing match.

Most owners believe their birds sing better under duress.

After hanging their caged birds in a pavilion, owners gathered at a railing about 50 feet away, shouting at them to elicit their best songs and hurling abuse at judges for ignoring their birds.

It was surprising the judges could hear the birds at all.

One top winner was a murai batu owned by Mr Andika Asa, a breeder who won a US$430 prize. As he left the pavilion, a spectator offered him more than US$8,000 for the bird. Mr Andika declined, saying it was worth nearly twice that.

Mr Andika, 40, a former university administrator, said he had bred the bird himself and spent countless hours training his champion.

To build its stamina, Mr Andika said, he and his son would slap the sides of its 6m cage to make it fly 500 laps a day. He also brought in "master birds" of other species so it would learn their songs.

Addressing the crowd, the police chief, Mr Bastoni Purnama, claimed that songbird competitions helped to save the species. (Mr Marison disputes this.) "We are involved in conserving birds in Indonesia that are decreasing in number or even in danger of extinction," Mr Bastoni asserted.

One trader, Mr Cin Aidiwanto, 52, said he employed 20 hunters to catch birds for him in Sumatra's largest national park, Kerinci Seblat.

He finances their expeditions, he said, with food, cash and cigarettes. "I send my hunters to the forest and they return in 10 days," he said. "Then I get all the birds they capture."

With the songbird population declining in the wild, Mr Marison has urged the government to make their protection a priority. A first step, he said, would be to close the bird markets - from small operations like Mr Cin's roadside stand to the sprawling Pramuka market in Jakarta, the biggest bird market in South-east Asia.

"Keeping the birds is not beneficial at all for the ecosystem or for the welfare of the birds," he said. "It is only for the pleasure of the owner."