ON THE BIOLOGY OF THE LARGE BIRDS OF PREY OF THE EMBU DISTRICT, KENYA COLONY.

Abstract

SUMMARY. The species of eagles occurring in Embu district are detailed, with general notes on the methods and scope of the study. The vegetation and climate of Embu district are described, and their effect upon eagles is discussed. Population and inter‐relations. The actual population of eagles and of the Secretary Bird in an area of approximately 146 sq. miles is given and their remarkable local concentrations are described. The inter‐relations of the various species are discussed from the points of view of territorial agressiveness and competition for prey. Detailed accounts are given of the breeding biology of Sagittarius serpentarius, Aquila verreauxi, A. wahlbergi, Hieraaëtus spilogaster, Polmaëtus bellicosus, Stephano‐aëtus coronatus and Circaëtus cinereus , and some information for Terathopius ecaudatus, Circaëtus pectoralis , and Aquila rapax, Hieraaëtus ayresi, Lophaëtus occipitalis , and Cuncuma vocifer . The headings for each species include: “Nests and nest‐building”, “Incubation period”, “Fledging period” (with special attention to food), and “Post‐fledging period”. The following special aspects of breeding behaviour are described and discussed: (1) Display, (2) Use of green branches, (3) Breeding seasons, (4) Breeding success, (5) Breeding frequency.