Observations on the Sooty Owl Tyto tenebricosa in South-east Queensland

Abstract

Field observations have been undertaken on Sooty Owls Tyto tenebricosa in the D'Aguilar Range in south-east Queensland since February 1983. Tape recordings were obtained of their calls and playback was used to locate the birds. The Owls were strongly territorial and during the courtship period (usually March-April) before egg laying they responded aggressively to playback At other times they were generally silent and did not respond. Data were obtained on vocalisations and routines during the breeding season: at dusk males gave a territorial call from or near the roost and then patrolled their territory, giving regular calls often at approximately 20 min. intervals from predictable points, for the first 2-3 h of darkness. They did not call on some nights during this period, and brooding females answered only the first evening call of the male. A previously unrecorded call (the male's food-presentation call during incubation) is described. Most breeding took place in winter (incubation June-July), with one record for December-January. A fledgling discovered in October was dependent on the adults until the following March; the male resumed territorial calling within two months of its disappearance. Six known territories in the study area have been permanently occupied by the Owls for 8-10 years.