Hissing as part of threat display in the Australian Owlet‐nightjar Aegotheles cristatus

Abstract

AbstractVocalisations of owlet‐nightjars Aegotheles sp. are poorly known, with the exception of the Australian Owlet‐nightjar A. cristatus. Among the vocalisations for the Australian Owlet‐nightjar, hissing has been described as part of threat display in three first‐hand early published reports (between 1848 and 1934). However, no reports of this behaviour have been published since 1934, despite a number of field studies on the breeding biology of the species, potentially casting doubt on the veracity of earlier reports. Here I describe an instance of hissing as part of a threat display (which also included flattening its body, with head up, swaying side to side and gape wide open) of an Australian Owlet‐nightjar cornered in a nest box. I compare my observations to the few published occurrences, pose questions as to the circumstances and conditions for this behaviour, review vocalisations of other owlet‐nightjar species and instances of hissing in Caprimulgiformes.