Observations were made on the overwintering ecology of black-necked cranes at Caohai, Weining County, Northwestern Guizhou Province in 1975 and 1978-1984. The results obtained are as follows;1. During the second and last ten days of October every year, flocks of black-necked cranes travel thousands kilometres to Caohai for overwintering. In the mid March, black-necked cranes begin to leave their overwintering area.The cranes stay in Caohai for nearly 140-160 days.2. The black-necked cranes are gregarious in...