HOST PREFERENCES AND BEHAVIOR OF OXPECKERS - COEXISTENCE OF SIMILAR SPECIES IN A FRAGMENTED LANDSCAPE

The host preferences and behaviour of red-billed and yellow-billed oxp eckers (Buphagus erythrorynchus and Buphagus africanus) were studied a t two locations in Kenya and combined with previously published data f rom East and South Africa. Red-billed oxpeckers are generally more com mon and have a greater niche breadth with respect to host preferences than yellow-billed oxpeckers, possibly due to the behavioural dominanc e of the latter. Otherwise, the host preferences sire remarkably simil ar: both prefer larger species of ungulates and are found predominantl y on species with manes. There are also no significant differences in the time-activity budgets of the two species controlling for site and host species, and differences in the proportion of time spent on diffe rent body parts of hosts are small in absolute magnitude even when sta tistically significant. Despite these and other basic ecological simil arities, no evidence for competitive displacement was detected by comp aring host preferences in areas of sympatry with areas of allopatry, e ven though each species appears to depress the population size of the other when sympatric. Traditional single-community competition theory cannot explain the geographical ecology of these two species. Instead, co-existence appears to be dependent on the patterns of extinction an d colonization characterized by metapopulations distributed among a fr agmented habitat.