White-throated Nightjar Eurostopodus mystacalis : Diurnal Over-sea Migration in a Nocturnal Bird

A White-throated Nightjar Eurostopodus mystacalis was photographed flying low above the sea in the Gulf of Carpentaria, Queensland, at ~1600 h on 25 August 2010. Sightings of Nightjars behaving similarly in the same area in the days before obtaining the conclusive photographs suggest that they were on southerly migration, returning from their wintering sojourn in New Guinea to their breeding grounds in Australia. Other relevant sightings are given, and the significance of this behaviour is discussed.