The yellow-breasted bunting, a once common migratory bird, has been driven to the brink of extinction in recent years as a result of illegal hunting.

The species was reclassified as “critically endangered” on the red list of threatened species by the International Union for Conservation of Nature on Tuesday. The status is one step from the highest level of “extinct in the wild”.

The decline of the population, which may have become extreme in the past 11 years, is likely to be driven by excessive trapping at migration and wintering sites, according to the red list of IUCN.

Back in 2000, the species was listed under “least concern”, the lowest level on the six-grade alert system.

Every year, yellow-breasted buntings migrate from Siberia southward to wintering grounds in south China and southeast Asia in a journey spanning up to 4,000 kilometers.

In South China’s Guangdong province, where the yellow-breasted bunting is considered a delicacy, there were records of consumption of the bird as early as the Qing Dynasty (1644-1911).

Once restricted to a small area of southern China, the practice of cooking yellow-breasted buntings has become more widespread and popular due to increasing affluence, and now hunters have to travel widely to find sufficient birds, according to the IUCN.

Despite a ban on selling the bird introduced by the Chinese government in 1997, illicit trading has been rampant, driving the species to the verge of extinction.

A bird protection volunteer told Beijing Youth Daily that through undercover investigations, it was found that most of the birds sold in Guangdong were transported from north China.

A man surnamed Liu from the northern province of Hebei told Beijing Youth Daily that back in 2000, more than 400 yellow-breasted buntings could be captured in one net; and in 2008, he could still catch more than 50 birds in one day. But today, only one or two can be caught in a day.

Liu said bird hunting is a lucrative business: a net costs only 15 yuan ($2.3), while a yellow-breasted bunting can be sold for about 20 yuan.

Liu said after the birds were captured, they would be put into cages to be fattened up for around 20 days. Then they would be suffocated in a sealed bag before being sold to south China.

And according to bird protection volunteers, sales of the yellow-breasted bunting in Guangdong have gone underground in recent years as a result of the government’s crackdown campaigns.

In some restaurants, where one yellow-breasted bunting is priced at up to 60 yuan, its name on the menu would be replaced with “rice bird” to avoid inspection from authorities.

Media reports show there are 28 cases of illegal hunting of yellow-breasted bunting in China from 2000 to 2013. In one case, more than 100,000 yellow-breasted buntings were seized by authorities in Guangzhou and Shaoguan, two cities in Guangdong province.

Despite its popularity among diners, the yellow-breasted bunting is not much different from other birds in terms of nutrition value.

The yellow-breasted bunting differs little from pigeons or quail in nutrition, said Zhu Yi, a food science professor with China Agricultural University. And as a migratory species, the birds may host unidentified viruses and many illegally captured ones may be poisoned to death, threatening the health of diners, he said.