Ageing Palm-nut vultures: A preliminary guide

Abstract

Significant knowledge gaps currently exist for the Palm-nut Vulture Gypohierax angolensis, particularly pertaining to the ageing of both nestlings and free-flying birds. Although the most reliable ageing scheme involves the detailed examination of a bird in the hand, a method based on more easily observable morphological characteristics is required. The captive breeding and rearing of an individual of this species presented an opportunity for the use of retrospective photography as a primary data source in this regard. Further cross-matching with additional images of free-flying wild birds was necessary for the development of descriptions considered more useful for field purposes. While this study ascertained that adult plumage is attained in the late fourth year, and provided much of the supplementary detail, it should be considered as preliminary. Further data pertaining to the nestling stages and general behavioural characteristics is required. Facilities that breed this species should thus be encouraged to collect and collate relevant mensural and photographic data going forward.