Concerning new research suggests the yellow-breasted bunting is taking on the same path to extinction as the passenger pigeon, which was wiped out by rampant hunting.

Up until a few years ago, the sparrow-sized songbird was one of the most common birds in northern Europe and Asia, the University of Muenster reported.  Recently the bird population has shown a dramatic decline, and has been added to the international Red List of endangered species as being "critically endangered." A new study is the first to outline the true severity of the species' population decline, and researchers have classified it as a "global collapse," primarily caused by widespread poaching in Asia.

Between 1980 and 2013 the birds' population decreased by as much as 90 percent, and its distribution range had shrunk by about 3,000 miles; it has become almost extinct in the European part of Russia.

"Our study is just scratching at the surface of a problem that is set to become an even greater issue - and other songbirds are affected too," said Johannes Kamp, the lead author of the study and a landscape ecologist at Münster University.

Hunting these songbirds has been illegal in China since 1997, but an increasing number are being killed along their migratory routes because they are considered to be a regional delicacy.

"Although the Chinese Government is trying to curb the poaching and illegal sale of the yellow-breasted bunting, it is very easy to buy the birds on the black market there," said Japanese ornithologist Simba Chan, the co-author of the study and representative of the Asian section of "BirdLife International."

In November, 2011, Chinese law-enforcement officers confiscated two million captured songbirds in two cities, 20,000 of which were yellow-breasted buntings.

"Although we cannot rule out other factors influencing the dramatic decline in the yellow-breasted bunting population, over and above poaching, a loss of habitat alone cannot explain the scale," Kamp said.

There have also been indications that disease and pesticides are playing a role in the birds' dramatic decline, but computer models using data from long-term monitoring of various breeding grounds in Finland, Russia, and Siberia, mainly point back to poaching as the root cause.

"The extremely widespread poaching of birds on their migratory route through Egypt is a big danger for our native birds - this is well documented," Kemp said. "However, we know much less about the Asian problem - although the dimensions are similar to those in the Mediterranean, if not even more dramatic."

The findings were published in a recent edition of the journal Conservation Biology.