Rapid colonisation, breeding and successful recruitment of eastern barn owls (

Abstract

Abstract Context The introduced house mouse (Mus domesticus) causes significant economic damage to Australia’s agricultural enterprises. As part of the Marna Banggara Rewilding Project on the southern Yorke Peninsula (SYP), the present study focused on the eastern barn owl (Tyto alba delicatula) as a potential bio-controller of mice, by providing nesting spaces where natural hollows are limited. Aims To design an appropriate pole-mounted wooden nest box, and to enhance barn-owl-breeding and house-mouse-hunting capacity on farmland adjacent to remnant native vegetation. Methods A prototype nest box was collaboratively designed with a nest box manufacturer using data from previous barn owl studies and anecdotal reports. Eleven pole-mounted wooden boxes with platforms were installed at distances >1.4 km apart on properties near Warooka, southern Yorke Peninsula (SYP), and monitored over a 6-month period using external trail cameras. Key results Of the 11 nest boxes installed, 55 percent were colonised within a month after establishment, and 82 percent were colonised within 7 months. Occupied nest boxes were actively used by paired owls for mating, breeding and rearing of chicks, which resulted in up to 35 fledgling owlets. Conclusions The nest box design successfully supported eastern barn owl colonisation and reproduction on the SYP. The inclusion of the platform not only provided easy, minimally invasive monitoring of barn owl activity and prey intake by researchers, but also increased usable space for barn owl behaviours, such as copulation and wing flapping. Implications The important nest box design elements featured in this paper, such as the platform, high entrance hole, predator-proof pole and rear door access, can be implemented in barn owl conservation, research and on farms where alternative nesting sites are limited.