Response to habitat modification by foraging Dark-chanting Goshawks Melierax metabates in a West African savanna

摘要: Anthropogenic habitat alteration has probably contributed significantly to the decrease of raptor populations in West African savannas. To evaluate impact degradation on foraging by sedentary Afrotropical raptors, we investigated differences microhabitat selection, effort and energy returns between Dark-chanting Goshawks Melierax metabates inhabiting natural transformed savannas Cameroon. We expected that agro-ecosystems have become unprofitable for due scarcity food resources. In both savanna types radio-tracked six mated, adult males during non-breeding season determined effort, time spent at each perch distance covered perches, intake through estimation value prey items. habitats had smaller home-ranges exploited their range more intensively than habitats. habitats, selected patches with comparatively tall trees, underlining importance Goshawks. The extent shrub herbaceous layer cover, agriculture tree density were other important predictors patch use, but differed shrub, cover positively associated use suggesting cultivated fields ground vegetation support resources agro-ecosystems. composition broad categories diet, comparable However, found indications proportion heavy-bodied lizard species among reptile items was higher whereas average lizards commonly caught latter. Mean height within home ranges, habitat, negatively related capture rates. Tree clearance livestock grazing thus favored greater rates offsetting a lower meal compared habitat. conclude may cope moderate land transformation, practices focused conservation trees would be beneficial maintaining exploitability under growing pressure.