Chinese researchers have used drones to monitor the living condition of Tibetan antelopes and have captured the 60,000 population of the species in Nagqu, southwest China's Tibet Autonomous Region.

The researchers, from the Shaanxi Institute of Zoology, studied the birth, migration, and ecological habitat environment of the Tibetan antelopes around the Qiangtang National Nature Reserve in Tibet Autonomous Region. They used research methods combining drone and ground observation.

The drones completed 12 flights of test observation in the reserve and covered more than 100 square kilometers. The images processed by the drones reached five centimeters in resolution, and were able to recognize newborn antelopes.

The 60,000 Tibetan antelopes were observed forming a big migration group, lining up a length of almost six kilometers, China Science Daily reported on Monday.

The population of Tibetan antelopes was calculated by the data processing software of the drones, said Wu Xiaomin, a researcher with the institute. The software divided the ground into grids and automatically counted the antelopes, helped by the infrared camera recognition.

The researchers believe the population of Tibetan antelopes has increased significantly this year, based on ground observation on them and data analysis. Disturbances during the migration are also gradually decreasing, while habitat quality has been effectively improved, and the ecological environment has been further restored.

The survival rate of litter after the long-distance migration of female Tibetan antelopes was about 80 percent in previous years. The researchers found the number reached more than 90 percent this year.

Since 2013, the researchers with Wu have studied the migration of Tibetan antelopes by using China's self-developed BeiDou Navigation Satellite System. They have recorded basic data, including the migration routes, times, and speed of the species around the Qiangtang National Nature Reserve where many endangered, wild animals live and breed.

Tibetan antelopes are mostly found in Tibet Autonomous Region, Qinghai Province, and Xinjiang Uygur Autonomous Region. The species is under first-class state protection in China.

In the 1980s, the Tibetan antelope population declined sharply from 200,000 to 20,000, due to illegal hunting. It has recovered thanks to the country's efforts to improve its habitat and crackdown on poaching.