DANGPLAT, Cambodia — A wake of vultures perches on the bare branches of a towering tree, dark shapes silhouetted against a pale sky, sharp beaks and talons ready to tear apart a dead cow laid out in a Cambodian jungle clearing.

This manmade "vulture restaurant" is part of efforts across Asia to save the critically endangered bird from extinction. Now there are tentative signs they may be paying off.

The population of vultures in Cambodia has doubled to 300 from as few as 150 in 2004. In India, they are still dying off, but their rate of decline has fallen.

These super scavengers may be regarded as messengers of death and doom, but in Asia, it is they who have suffered one of the natural world's greatest population crashes of recent times.

From tens of millions, numbers of the three main species have plummeted to well below 60,000, says British expert Richard Cuthbert. They have gone extinct in several countries, including Thailand, Vietnam and Laos, and are still declining outside of Cambodia.

While the greatest losses have been in Asia, most vultures outside the region are also deemed critically endangered or threatened.

Scientists say they will probably never fully revive; they were once so numerous in Cambodia that airplanes had to dodge flocks of them. But some reasons for hope have emerged.