HABITAT SEGREGATION OF MALE AND FEMALE RED-BACKED SHRIKES LANIUS-COLLURIO AND LESSER GREY SHRIKES LANIUS-MINOR IN THE KALAHARI BASIN, BOTSWANA

Lesser Grey Shrikes and Red-backed Shrikes have much smaller ranges on the non-breeding grounds in the Kalahari basin than during breeding. This study investigated whether, as a result of competition, habitat s egregation occurs on the non-breeding grounds. Migrant shrikes were su rveyed in point-transect counts in 19 vegetation types in Botswana. Th ere were clear differences in habitat distribution between the species , and also between the sexes in the Red-backed Shrike. Female Red-back ed Shrikes occupied more densely wooded bushveld than males, while Les ser Grey Shrikes occupied the most open habitat and overlapped more fr equently with male than with female Red-backed Shrikes. More subtle di fferences along gradients of herbaceous ground cover suggest that diff erences in habitat quality may be involved, the dominant species (Less er Grey Shrike) occupying, on average, the best and the most subordina te birds (female Red-backed Shrikes) the poorest habitat. The sex diff erences in habitat occupation on the non-breeding grounds in the Red-b acked Shrike are the first such differences documented in any Palaearc tic-African migrant passerine.