Where to sleep in the city? How urbanisation impacts roosting habitat availability for an apex predator

Abstract

Increased urbanisation is placing respite areas for wildlife under stress, with the impact of anthropogenic disturbances such as noise, artificial light and infrastructure compounding as urban areas expand and become more populated. One essential, and sometimes overlooked behavioural activity is where urban wildlife sleep or rest. This is especially important for urban predators that are wide-ranging and exhibit specific ecological requirements. The powerful owl (Ninox strenua) is one such species. To ensure the future survival of urban powerful owls it is critical that we understand where they choose to roost/sleep and why. To determine these roosting characteristics, we used roosting data collected from GPS tagged powerful owls across Melbourne, Australia and examined these data at different spatial scales to provide a holistic understanding of habitat selection. At the landscape scale, potentially suitable roosting habitat was restricted heavily by urban and agricultural land use. Population-wide, roosts were located within dense tree cover with some flexibility between individuals in distance to river systems and tolerance of road density. At the microhabitat-scale, individual owls displayed flexibility by roosting in a variety of indigenous, non-indigenous native and exotic tree species. These considerations will assist urban planners to conserve suitable roosting habitat, while restoration efforts should be prioritised on private land and along river systems where roosting habitat can be enhanced and expanded, increasing landscape connectivity for other wildlife.