Nesting Behaviour and Juvenile Development of the Tawny Frogmouth Podargus strigoides

Abstract

Nesting behaviour and juvenile growth rate of Tawny Frogmouths Podargus strigoides was studied in Eastwood State Forest near Armidale, New South Wales. In the winter of 1997, five birds (three males and two females) were fitted with radio transmitters. Four of these birds were involved in nesting attempts. Their absence or presence on the nest were monitored continuously with receiver/loggers placed under the nest tree. After hatching, nestlings were inspected at four to seven day intervals and their body mass recorded. Incubation and brooding during the day was only by the male; both sexes attended during the night. Incubation lasted between 28 and 30 days and the mass of new hatchlings was approximately 19 g. The young gained on average 8.3 g per day and mass increased in a linear fashion until fledging. Fledging occurred simultaneously for siblings between 26 and 30 days after hatching, at a mass of about 250 g, approximately 50% of adult mass. In some cases the younger sibling roosted on the ground for several days, because it could not fly strongly.