Migratory and calving behavior of Tibetan antelope population

Abstract

A migratory population of female Tibetan antelope or chiru was studied on its calving ground in the western Kunlun Mountains, Xinjiang in June-July 2005. It was estimated that 4 000-4 500 females were in the 1 200 km 2calving area but most births were concentrated in 350 km 2. The habitat at 4 500-5 000 m in elevation had vegetation coverage of less than 5%, principally the dwarf shrub Ceratoides compacta. Young were born 18 June-7 July with a peak 24 June-3 July. Only about 40% of adult females had young, a low fecundity possibly the result of heavy winter snows leading to poor physical condition. Wolf, red fox, and birds of prey killed a few chiru but predators were scarce; most mortality was unrelated to predation. Females arrived at the calving grounds in late May and early June from the west of Tibet, and by early July started their return migration. It remains unclear why chiru migrate to that site. Analysis of chiru food plants showed no marked difference in nutritive values at this season between the calving grounds and the southern range. Escape from predators, parasitic insects, and people with their livestock may all have a role. Based on the study, we suggest that the main calving ground requires strict protection from disturbance, and a large reserve in the region needs to be established.