The breeding ecology and behaviour of the augur buzzard Buteo augur in relation to different land-uses in the southern Lake Naivasha area, Kenya
thesisposted on 15.12.2014, 10:33 by Munir Z. A. Virani
A comparative study of the breeding ecology and behaviour of the augur buzzard Buteo augur was made between 1995 and 1998 in the southern Lake Naivasha area, Kenya. Populations in Hell's Gate National Park (Hell's Gate) a protected area, and two other locations (both modified by humans) within the Lake Naivasha environs - Mundui and Sulmac-Oserian were compared. The main aspects studied were nesting density, nest-site selection, breeding behaviour, diet, hunting success, prey availability, breeding seasonality and breeding performance. The methods used were nest searches, augur buzzard ringing, nest and foraging observations, pellet and prey remains collection and analyses, transect counts to determine prey availability, nest site habitat data collection and recording the outcome of active nests.;Mundui had the highest density of augur buzzards at 0.83 pairs per km2 compared to Hell's Gate (0.28 pairs per km2) and Sulmac-Oserian (0.23 pairs per km2). Augur buzzard pairs were more widely spaced in areas where human impacts had increased. Augur buzzards nested mainly in cliffs (in Hell's Gate) or trees (partly in Hell's Gate, exclusively elsewhere). In Numdui and Sulmac, augur buzzards selected mature, large canopied Acacia xanthophloea as nest trees while in Hell's Gate and Oserian, mature Euphorbia magnicapsular trees that grew on the steepest slopes were selected.;Augur buzzard pairs in the lake environs spent more time caring for chicks than their counterparts in Hell's Gate. This was shown by increased maternal care and paternal foraging which resulted in larger broods and more prey deliveries to nests respectively. The factors responsible for these were an abundant food supply coupled with reduced predation pressure and inter/intra-specific interactions. Augur buzzards in Hell's Gate exploited a broader range of prey, while those in the lake environs specialised on rodents, particularly mole-rats.