Raptors in the east African tropics and western Indian Ocean islands: State of ecological knowledge and conservation status

--From our review of articles published on diurnal and nocturnal birds of prey occurring in Africa and the western Indian Ocean islands, we found most of the information on their breeding biology comes from subtropical southern Africa. The number of published papers from the east African tropics declined after 1980 while those from subtropical southern Africa increased. Based on our KnoMedge Rating Scale (KRS), only 6.3% of breeding raptors in the east African tropics and 13.6% of the raptors of the Indian Ocean islands can be considered Well Known, while the majority, 60.8% in mainland east Africa and 72.7% in the Indian Ocean islands, are rated Unknown. Human-caused habitat alteration resulting from overgrazing by livestock and impacts of cultivation are the main threats facing raptors in the east African tropics, while clearing of forests through slash-and-burn methods is most important in the Indian Ocean islands. We describe conservation recommendations, list priority species for study, and list areas of ecological understanding that need to be improved. I•y WORDS: Conservation; east Africa; ecology; western I dian Ocean; islands; priorities; raptors; research. Aves rapaces en los tropicos del este de Africa yen islas al oeste del Oc•ano Indico: estado del conocimiento eco16gico y de su conservacitn RESUMEN. --De nuestra recopilacitn de articulos publicados sobre aves rapaces diurnas y nocturnas que se encuentran en Africa yen las islas al oeste del Octano Indico, encontramos que la mayoria de la informaci6n sobre aves rapaces residentes se origina en la regi6n subtropical del sur de Africa. E1 nfimero de publicaciones provenientes de los tr6picos del este de Africa, declint despues de 1980, mientras que aquellos del subtrtpico del sur del continente aumentaron. Con base en nuestra escala de valoraci6n del conocimiento solo el 6.3% de las especies residentes en los tr6picos del este del Africa y el 13.6% de las aves rapaces de islas del Ocaano Indico pueden ser consideradas como Bien Conocidas, mientras que la mayoria 60.8% del este de Africa y 72.2% de las islas al oeste del Octano Indico fueron clasificadas como Desconocidas. La alteracitn de habitats de origen antrtpico como resultado del sobrepastoreo y los impactos de la agricultura son las principales amenazas para las aves rapaces de los tr6picos del este de Africa, mientras que la deforestaci6n a partir de la quema y tala de bosques es la amenaza mas i•nportante en las islas del Octano Indico. Describimos recomendaciones de conservacitn, identificamos las especies prioritarias para estudiar e identificamos las areas de entendimiento ecoltgico que deben ser mejoradas. [Traducci6n de C•sar M•rquez] Raptors are an important tool to focus conservation strategies locally, regionally, and globally (Watson 1991). They can be used as "umbrella species" because their large home ranges and low nesting densities necessitate that any protected areas encompassing viable populations or complete communities protect sufficient habitat and populations of most, if not all, other species in the food • Also National Museums of Kenya, Nairobi and Leicester University, U.K. web below them (Thiollay 1992). Because of their top positions in terrestrial and aquatic food webs, raptors can be used as indicators of worldwide pollution by pesticides (Newton 1979). Changes in raptor distribution or abundance can serve as a measure of our impact on landscapes, even in remote areas (Reichholf 1974). Finally, raptors are popular and charismatic and several species have become significant "flagships" for increasing public interest and support of conservation programs (Burnham et al. 1992, Thiollay 1992). This paper combines our collective knowledge