Breeding behaviour and diet of a family of barking owls 'Ninox connivens' in South-eastern Queensland

The breeding behaviour and diet of the Barking Owl 'Ninox connivens' were investigated in coastal south-eastern Queensland, by observation and by analysis of pellets and prey remains from beneath the nests and roost-sites of one Owl family in spring 2002, 2003 and 2004. The Owls raised four fledglings: two in 2002 and two in 2004, in a different nest, after failure in 2003. Aspects of their nest-sites, roost-sites and behaviour are described. The female roosted in the nest-hollow until the third week of the nestling period, which lasted -36 days. The Owls' diet consisted of 25% mammals, 10% birds and 65% arthropods by number, and 74% mammals (mostly gliders Petaurus, 71%),24% birds and 1% arthropods by biomass. There was some interyear difference in the relative contribution of mammals and birds, with earlier laying by the Owls when mammalian prey predominated and later laying when avian prey predominated. Mammals may be the more rewarding prey, enabling female Owls to reach breeding condition early in the season, with subsequent benefits for early-fledged offspring.