A review of foraging and feeding behaviour, and associated anatomical adaptations, in Afrotropical nightjars

Abstract

Nightjars (Caprimulgidae) in the Afrotropical Region feed almost exclusively on night flying insects, which they hunt during twilight and moonlight. Without the benefit of echolocation, they detect prey visually before pursuing and capturing it in this dim light. They are superbly equipped to do so, utilising a suite of anatomical adaptations in different hunting strategies. This paper, based on a comprehensive literature review, examines the facts and fallacies surrounding those adaptations and strategies. The adaptations, common to most of the species, are reflected mainly in the greatly enlarged eyes and mouth; the greatly reduced bill, tongue and crop; the structure of the lower jaw and the rictal bristles; and the sensitive nature of the palate. Hunting strategies vary between species, and even within species, according to habitat, prevailing light conditions and availability of insect prey. The most commonly used strategy, employed by all species at times, is to hawk single insects from a terrestrial or elevated observation post, while some species prefer to make multiple captures during sustained flight. Prey is generally swallowed live and whole, without preparation. Diets differ between species, perhaps as a result of differences in hunting method or mouth size, rather than deliberate prey selection by each species or competition between species. Migration is a feeding adaptation.



(Ostrich: 2003 74(3&4): 187–204)