Oxpecker host selection appears to be governed by an array of factors affecting the efficiency of foraging for ticks, with optimally foraging oxpeckers choosing those hosts that maximize tick intake and/or minimize search time. We studied yellow-billed oxpeckers Buphagus africanus (Linnaeus) at Matobo National Park, Zimbabwe, in order to examine the relationship between host selection and seasonal tick abundance, host characteristics and water availability. Preference ranks were highly correlated between the dry and wet seasons, implying that relative tick burdens of