A census taken 10 years ago put the population of the endangered animals in the wild at just 1,596, down from about 2,500 in the 1970s.
Since then, experts said, constant activities such as road construction and laying of railroad and utility lines have intruded into the panda habitat -- driving the extremely shy animals into isolated mountain enclaves, where they are vulnerable to inbreeding and starvation, the Los Angeles Times reported.
Sightings of pandas in the region have become a rarity, Dai Bo, wildlife biologist with China's Forestry Ministry, told the Times.
"To be honest, I've been working in these mountains for 20 years and I've never seen a panda in the wild," said Dai, who is leading a six-person team through the fog-covered mountains of Sichuan province to conduct the next census. Even finding panda droppings to aid in the census effort has become a major task.
The Times said current plans call for more than 100 people to search about 12,000 square miles of treacherous mountain passes in Sichuan and nearby Gansu and Shaanxi provinces to look for pandas or its droppings.
The droppings, their quality and locations can help researchers determine how many pandas are in a particular area.
Sarah Bexell, director of conservation research at the Chengdu Research Base, said: "The Chinese government is trying so terribly hard to protect their national treasure, but until humans globally get our population under control and our consumption habits under control, it's impossible to save wildlife," she said.
This is more true for pandas, which dislike humans so much they would rather starve than enter an area with humans to find fresh sources of food.