Breeding performance in relation to nest-site substratum in a buff-necked Ibis (Theristicus caudatus) population in Patagonia

JOSÉ ANTONIO DONÁZAR; OLGA CEBALLOS; ALEJANDRO TRAVAINI; ALEJANDRO RODRIGUEZ; MARTÍN FUNES; FERNANDO HIRALDO

THE CONDOR

COOPER ORNITHOLOGICAL SOC

Año: 1994 vol. 96 p. 994 - 1002

0010-5422

In northern Argentinean Patagonia, Buff-necked Ibis (Theristicus caudatus) nest on different substrata: cliffs, trees, and marsh vegetation. According to the ideal-free distribution hypothesis, this polymorphism may be due to the occupation of the best breeding habitats by dominant individuals and the relegation of the subdominant birds to marginal substrata with lower probability of achieving successful breeding. We investigated whether there were any variations in the breeding performance among colonies and whether these variations were related to the breeding substratum.