Nesting and parental behaviour of Andean Condor Vultur gryphus in the Andes of central Chile

Abstract

Birds invest significant energy in parental care, often through biparental cooperation, to enhance offspring survival by provisioning food and protection. The Andean Condor Vultur gryphus, a long-lived and monogamous species, exhibits shared parental roles in remote nesting sites, although its reproductive ecology in the wild remains poorly documented due to the inaccessibility of nests and limited field observations. From January 2006 to October 2009, we searched for Andean Condor nests in the Andes of central Chile. We found five nests and we determined that the reproductive period in central Chile begins in early- or mid-August. From October 2007 to May 2009, we studied parental care in two pairs of condors, recording behaviour patterns associated with reproductive events. The behaviours we observed were: a) male or female enters and stays inside the nest, b) parent-chick interactions without food delivery, c) nest guarding, d) coming to the nest with food, and e) chick feeding. At the locality of Farellones the male entered the nest (69%) and came to the nest with food (65%) more often than the female (30.4% and 35%, respectively), while the female guarded the nest (57.6%) more often than the male (42.4%). However, at the El Ingenio site, the male entered the nest (59.1%), fed the young (63.6%), and guarded the nest (60%) more often than the female. In both the Farellones and El Ingenio localities, the amount of time that the male and female remained in the nest, interacted with the young, and guarded the nest did not differ considerably. This study does not allow us to determine whether these observations correspond to a general behaviour pattern of this species in central Chile, or only applies to the two breeding pairs of condors studied. Therefore, it is necessary to expand the study of condor reproductive behaviour to other areas of its distribution.