Host preferences and behaviour of oxpeckers: co-existence of similar species in a fragmented landscape

Abstract

The host preferences and behaviour of red-billed and yellow-billed oxpeckers (Buphagus erythrorynchus and Buphagus africanus) were studied at two locations in Kenya and combined with previously published data from East and South Africa. Red-billed oxpeckers are generally more common and have a greater niche breadth with respect to host preferences than yellow-billed oxpeckers, possibly due to the behavioural dominance of the latter. Otherwise, the host preferences are remarkably similar: both prefer larger species of ungulates and are found predominantly 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 different body parts of hosts are small in absolute magnitude even when statistically significant. Despite these and other basic ecological similarities, no evidence for competitive displacement was detected by comparing host preferences in areas of sympatry with areas of allopatry, even 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 and colonization characterized by metapopulations distributed among a fragmented habitat.