ABSTRACTAimTo test the prediction that deviations of species from the positive interspecific relationship between abundance and occupancy (a measure of geographical range size) are related to differences in dispersal.LocationGreat Britain.MethodsQuantitative data on the abundances, occupancy and dispersal distances of British birds are compared using phylogenetic comparative methods.ResultsMeasures of natal and adult dispersal distance, and the intraspecific variance in these parameters, explain little variation in occupancy in addition to that accounted for by population size. Individual dispersal variables failed to explain significant variance when added individually to a model with population size as a predictor. Migrants and species using wet habitats tend to disperse further than residents and dry habitat species. Analysing these four groups separately revealed effects of dispersal only on the occupancy attained by dry habitat species.ConclusionsThe only consistent predictor of occupancy in these analyses was population size.