KUNMING, May 26 (Xinhua) -- A three-year study conducted by Chinese scientists has shown a dramatic population decline of the Green Peafowl, one of the world's most threatened pheasants, in China over the past three decades.

The survey from 2014 and 2017 recorded the number of the birds in China as between 183 and 240, only around a third of the number recorded in the 1990s, according to Kong Dejun, the first author of the research paper, which was published online in the journal Avian Research earlier this week.

Given the elusiveness of the birds and undetected habitats, the population of Green Peafowl in the country is estimated at less than 500, said Kong, an associate professor in the life sciences at Kunming University in southwest China's Yunnan Province.

The bird's population was estimated at between 800 and 1,100 in the 1990s. There had been no updates on the population and distribution of the species since then, hindering effective protection of the bird.

The species is classified as being endangered on the International Union for the Conservation of Nature Red List, and is under top protection in China.

The birds are native to the tropical and subtropical forests of Southeast Asia and southern China. In China, they have only been spotted in Yunnan since the 1990s.

The species used to live in 54 counties in Yunnan, while the survey only found them in 22 counties.

Threats to the species include poaching, habitat loss, poisoning and hydropower construction, the study found.

The size of each flock of the birds has also shrunk to three to five from eight to 20 three decades ago, Kong said. "But the good news is we also detected large flocks of 18 to 27 members, which increases our confidence in population recovery of the bird."