They scare goats, which are grazing on the cliff and not being watched by a shepherd, by diving suddenly toward them and prey on those falling off the cliff, Li said.

As a result, Li asks visiting friends and others to bring intestines of chicken and fish as well as rotten meat for his team to put in places away from the goats, so that the vultures will leave the goats in peace.

Also, in springs and autumns for the past eight years, Black Leopard workers have gone to a remote village nestled in mountains in Hebei to help prevent boars from ravaging villagers' crop fields.

Boars began to pose a serious issue more than 10 years ago, Zhao Chunjiang, 51, an official of the village, said.

The animals come to the village every year and destroy farmland, most of which is planted with corn, Zhao said.

Villagers have to bang a gong and watch out for several hours at night to keep the boars away. "If we left them alone, there would be nothing left to harvest," Zhao said. But the boars keep coming back.

Li and his teammates have developed several methods to tackle the problem. They patrol the mountains and have hung laser disks that deflect sunlight and down the tree branches to disrupt the boars' vision.