A review of the evidence for the translocation of eggs and young by nightjars (Caprimulgidae)

Abstract

I undertook a review of evidence for the translocation of eggs and young by nightjars through a comprehensive search of the literature. I found that most of the evidence was based on hearsay, supposition, a misunderstanding of nightjar behaviour, or on the repetition of a story going back 200 years to Le Vaillant, via Audubon. There is no satisfactory direct evidence of any nightjar deliberately airlifting its eggs or young away from a disturbance. This conclusion is based on 10 studies by ornithologists across five continents, involving over 522 nests of 13 species. Accidental airlifting occurs occasionally when an egg or young chick gets stuck to the ventral plumage of the sitting adult. This is most likely to occur near the time of hatching. A nightjar can move an egg along the ground for a short distance, either by placing its lower mandible over the egg and then walking backwards while rolling it, or by rolling it forwards with its feet. Nightjars regularly move their chicks, especially after a disturbance. They do so by first moving away themselves and then calling. The chicks, who are highly mobile within hours of hatching, respond immediately by running to the parent birds.

Ostrich 2007, 78(3): 561–572