PARTIAL MIGRATION IN THE MASKED WEAVER PLOCEUS VELATUS IN SOUTHEASTERN BOTSWANA

Masked Weavers (n = 544) were caught randomly during ''measured effort ringing'' in southeastern Botswana between January 1991 and January 1 994. Furthermore, samples were taken at a roost near Gaborone (n = 248 ) in June 1993 and at Maun (n = 173) in northern Botswana in August 19 93. Clear differences were found between the samples in terms of sex a nd age structure. Masked Weavers are evidently partial migrants in sou theastern Botswana. A large proportion of the juveniles emigrated duri ng winter and during the very dry winter of 1992, most adult females a lso moved out. Adult males were more sedentary.