Variation in the quality of parental care at falcon nests in South Africa as evidence for postulated differences in food availabi lity.

Parental care by Peregrine Falcons Falco peregrinus an d Lanner Falcons F. biarmicus during the nestling period was studied in two areas of South Africa. Comparisons were made between the quality of care administered to broods of Peregrine Falcons at nests in tropical (the Soutpansberg) an d temperate (the Cape Peninsula) environments, and to broods of sympatric congeners (Peregrine Falcons and Lanner Falcons) in the tropics, to investigate postulated species- and area-specific differences in food availabi lity. Timelapse photography was used to measure provisioning rates and adult attendance at nests . In all three study populations, provisioning rates were positively correlated with brood size, and attendance was negatively correlated with the age of young . The quality of parental care provided by Cape Peninsula Peregrine Falcons and Soutpansberg Lanner Falcons was superior (provisioning rates were over 20% higher and adults were more attentive at the nest) to that of Soutpan sberg Peregrine Falcons. Direct observations and diet information from the an alysis of prey remains suggested that female participation in the foraging effort was greatest at Peregrine Falcon nests in the Soutpansberg, which may have compromised nest security. The relatively poor quality of parental care by Peregrine Falcons in the Soutpansberg is symptomatic of food shortage for this specialist raptor in the tropics, in contrast to the more generalised Lanner Falcon

Jenkins A.R . 2000, Ardea, 88(1): 17-32