Breeding ecology of the Sacred Ibis Threskiornis aethiopicus in the Free State, South Africa

Studies on the breeding ecology of the Sacred Ibis Threskiomis aethiopicus were carried out at a few colonies in the Free State province, South Africa, but were focused on one colony at Wolwekop, Dewetsdorp district, in an extensive farmland in the Transitional Cymbopogon-Themeda grassland. In the Free State a 2-3 fold increase in the Sacred Ibis breeding population took place during the years 1972-1995, attributed to the intensification of agriculture practices and the creation of new dams. Sacred Ibis nests were built mainly of sticks and twigs, but quite often greenery was used. Nests were situated relatively low in the tree, and in each colony they were subdivided into smaller groups. If a colony was situated on an island, some nests, or all, were placed on the ground. Hatching and fledgling success varied in relation to season and locality. Two peaks occurred in daily activity of adult birds : one between 7h00 and 10h00, and other between 17h00 and 18h00. Chick's growth form hatching to the age of 22 days were also investigated.