Prey Abundance and Patch Usage for Foraging by Buteo augur in the Afro-Alpine Habitats of the Bale Mountains National Park (BMNP), Ethiopia

Quantifying diet related responses of species is key for understanding their functional relationship with their environment. Variation in its magnitude reflects differences in the adaptive value of spatial locations within the distributional range of a species. Amongst the key factors that may account for such variation, differences in prey abundance are critical particularly for predatory species. In this paper, the relationship of the use of patches for foraging by B. augur with prey abundance in the Afro-alpine habitats of the BMNP was studied. Data on the frequency of usage of patches for foraging by B. augur and the abundance of suitable prey species was collected by having samples at three contrasting areas that reflect the overall variation in the Afro-alpine system. Classification of patches using prey abundance predicted their group membership along with the intensity of foraging by B. augur, which varied with very high significance. Two latent variates that were computed by linearly combining the abundance of prey species explained significantly B. augur's foraging frequency significantly in a quadratic and linear regression models. The first variate that explained most of the group variation in prey abundance predicted the frequency of foraging by B. augur significantly in a quadratic model that explained 66 % of the variation. This variate was mainly defined by the abundances of A. blicki, L. melanonyx and O. bottae. The second variate with a smaller proportion of group variation contributed significantly to the predictive value of a linear regression model that explained 77 % of the variation in the data set. The discriminant scores of this variate were mainly contributed by A. blicki and S. albocaudata. Interpretation of our results indicated that A. bilicki along with S. albocaudata and L. melanonyx may have played principal role in affecting B. augur's foraging decisions across patches. Generally, in this paper we determined the main prey species that affect the foraging behaviour of B. augur for the first time and presented a body of information and interpretation essentially laying the foundation for further understanding of the species ecology in the BMNP and also in Ethiopia. The findings also assist the general conservation effort in the NP and also initiatives that may specifically target B. augur.