Breeding Ecology of Two Widely Separated Populations of Abdim's Storks (Ciconia abdimii)

ABSTRACT

An understanding of the ecological differences between disparate wildlife populations is important for determining different drivers of population change, especially for migratory species. We studied and compared the breeding ecology of two populations of Abdim's Storks (Tigray Region, Ethiopia, and Bauchi State, Nigeria) separated by over 3000 km. The breeding phenology of both populations was highly synchronised, with no statistical difference between nest initiation dates. The frequency of nest initiation and timing of fledging were not related to daily rainfall in either country, somewhat dispelling the traditional view that Abdim's Stork nesting is closely tied with the rains. However, earlier nest initiation significantly increased the probability of fledging at least one nestling. Fledging rates and productivity were significantly higher in rural Nigeria than urban Ethiopia, which may be explained by high human disturbance at Ethiopian nests. This first comparative study on widely separated breeding populations of Abdim's Storks demonstrates important similarities and differences in breeding outcomes, and highlights the need for further comparative studies at the population and range level.