Breeding home range movements of pre-fledged brolga chicks, Antigone rubicunda (Gruidae) in Victoria, Australia – Implications for wind farm planning and conservation

Abstract

Built infrastructure, such as wind farms and power lines, can impair wildlife movement. These barriers may displace individuals from important habitats due to direct mortality or disturbance. Understanding animal movement patterns can help avoid such impacts and manage population level effects. Avoiding impacts and implementing mitigation strategies is difficult when movement and home range information is lacking. Impact at breeding sites may negatively affect population recruitment. The number of wind farm developments is increasing in southern Australia within the core range of the south-eastern brolga (Antigone rubicunda) population. The main threats to this wetland bird include habitat loss, chick predation and collisions with power lines and fences. Wind farms may increase collision and mortality risk, and habitat displacement but the impact is difficult to assess or mitigate, as movement patterns and home range size are unknown. We deployed 11 GPS transmitters on pre-fledged brolga chicks at breeding sites in 2010–2012, including one at a wind farm, to investigate movement and home range use of brolga chicks. Brolga chicks moved 442 m on average, to and from night roost wetlands (range: 0 m–1964 m). The average breeding home range was 232 ha, estimated with a Brownian bridge movement model at 95% UD, but varied greatly between individuals (70 ha–523 ha). Brolgas used either single or multiple wetlands, and those using multiple wetlands either switched between them or relocated permanently. Information from this study can be used to design turbine–free buffers at brolga breeding sites and to manage breeding wetlands.