Call function and vocal activity in the Southern Bald Ibis at a breeding site. - G. Kopij. - Berkut. 13 (2). 2004. - P. 258-261.
Studies were carried out in a breeding colony at Welgelegen, eastern Free State, South Africa in 1994. Seven different calls in the Southern Bald Ibis were distinguished and their function has been determined: ‘clangor’, alarm, barking, copulation, snoring, greeting and begging. In the pre-laying phase, breeding and non-breeding pairs were equally vocal. Among breeding birds females were more (60.0 %) vocal than males (40.0 % of 402 calls recorded), while among non-breeding paired birds the reverse was true (males: 57.5 %, females: 42.5 %; n = 134 calls recorded). At the nest, breeding birds were more vocal during the incubation than during the pre-laying and nestling phases, while non-breeding paired birds are more vocal at the beginning of the breeding season than latter. During the day, breeding birds are more vocal in the morning (700–1000; 40.5 %), while non-breeding paired birds are more vocal around the noon (1000–1400; 50.6 %) and in the evening (1600–1800; 23.4 %). [English].
Key words: Southern Bald Ibis, Geronticus calvus, South Africa, vocalization, vocal activity.
Address: Department of Zoology & Ecology, Agricultural University of Wroclaw, ul. Kozuchowska 5b, 51-631 Wroclaw, Poland.