Abdim\'s Stork Ciconia abdimii in Niger: population size, breeding ecology and home range
AbstractAbdim's Stork is a common breeding bird in most human settlements across the Sahel. However, very few studies have surveyed the population and described its breeding and feeding ecology during the breeding season. We identified the breeding range in Niger, surveyed nests in 23 villages/towns and, based on the number of villages and towns in the breeding area, estimate the total breeding population for Niger at 18 157 pairs (95% CL ± 9 160). Breeding success was 2.6 fledglings per successful pair (95% CL ± 0.28, range 1–4, n = 36), suggesting a total post-fledging population of c. 83 500 birds (95% CL ± 51 267), excluding any non-breeding (sub)adults. The home range of six satellite-tagged breeders in 2003 was 10–120 km2 (median 36 km2); birds adjacent to a major river rarely used that wet habitat. Home ranges were consistently larger, though not significantly so, in the post-fledging period than in the nestling season. The tagged adults stayed in their nesting areas until 16–59 d after the young fledged. After leaving the nesting area, most of the tagged birds moved to one or more staging areas within 300 km of the nest site and stayed there for an additional 8–33 d before the onset of migration. The following season (2004), four out of five tagged storks returned to the previous years' nest (one lost its nest), and started incubation 10–25 d after arrival. Onset of incubation (mean 29 May) varied from 4 May to 4 July (earliest in the east along the River Niger) but with large local variation, with the earliest breeders starting shortly after the first rain in each area.
Ostrich 2008, 79(2): 177–185