Effects of fragmentation on artificial nest predation in a tropical forest in Kenya

Nest predation has been established as a leading source of reproductive failure in songbirds. Numerous studies, conducted primarily in the Northern Hemisphere, have linked high rates of nest predation with fragmentation and habitat edges. To date, virtually no such studies have been conducted in Tropical Africa. Here we investigate the effects of disturbance level and edge on depredation of artificial avian nests in six fragments of Kakamega Forest, Kenya. We found that nest losses were higher at the edge than in the interior as often reported in previous studies. Surprisingly, nest predation was highest in the least disturbed fragments. One possible explanation for these findings is that top predators are missing from Kakamega Forest, allowing nest predator populations to increase in all fragments, while in the highly disturbed fragments, domestic dogs might be surrogates for top predators. Alternatively, human activity may itself lead to a decline in mesopredator populations.