Flocking behaviour of Chinese grouse Bonasa sewerzowi was studied in winter 1994-95 at Lianhuashan Natural Reserve in Gansu Province. Data were obtained from 18 radio-marked birds and observations. Flocks of 4-5 birds were first observed in mid-October when broods were dispersing. Flock size increased in early December to 13-14 birds and varied in different habitats. Spruce Picea spp. and fir Abies spp. trees served as cover as 80.8% of observations of feeding Chinese grouse were within 15 m of spruce or fir. From December to March, Chinese grouse favoured the fruits of sea buckthorn Hippophae rhamnoides, which was distributed in clusters on south slopes where no coniferous trees occurred for cover. Flocks larger than five birds were observed when Chinese grouse were feeding on sea buckthorn. The main reasons for flocking were food concentration and mutual vigilance against avian predators. Flock structure and stability were stable during winter, but some birds changed flocks. In winter, most birds abandoned their territories although some did not. Some adult males occupied territories in winter; however, young males and females were more often observed in flocks.

Key words: Bonasa sewerzowi, China, Chinese grouse, foraging, winter flocking behaviour

Yue-Hua Sun, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China