In western rollers, autumn migration occurred on two fronts: rollers from the south-west of the region took a westerly route along the Atlantic coast of West Africa and then turned east along the savanna belt, whereas those from north-east Spain and southern France took a more direct route across the Sahara. Interestingly, individuals from both sides of this migratory divide eventually converged at similar autumn stopover sites and wintered in the same region of south-west Africa. For eastern rollers, there was no evidence of any detours shortening the southward Sahara crossing. Our study supports previous work identifying the northern savanna zone, particularly the Lake Chad basin, as an important autumn stopover site for rollers from western European populations.

All tracked rollers wintered in the tropical grasslands, savannas and shrublands (Olson et al., 2001) of southern Africa, 4000–8600 km away from their breeding sites. Although the winter ranges of different (and often distant) breeding populations overlapped, the distribution of wintering rollers with respect to their breeding origin was significantly non-random. In addition to strong longitudinal correlations between breeding and winter sites, there was a correlation between pairwise distance matrices of breeding and winter sites. These results suggest that migratory connectivity is neither absent nor strong, but somewhere in the middle of the ‘weak–strong’ continuum defined by Webster et al. (2002).