Urbanisation impacting larger Australian birds of prey

Increasing urbanisation is having negative impacts on biodiversity globally, but the responses to this urbanisation by species in the Southern Hemisphere is poorly understood compared to the Northern Hemisphere.

Now, new research led by Flinders University’s BirdLab in Australia and the University of Vienna, Austria, has started to chip away at this knowledge gap by evaluated the ‘urban tolerance’ of 24 Australian raptor species.

They found that 13 of the smaller species show higher tolerance and were better adapted for living in urban areas than the 11 larger-bodied species.

Specifically, the eastern barn owl (Tyto javanica), brahminy kite (Haliastur indus), and the Australian Hobby (Falco longipennis) had the highest tolerance to urbanisation, while the brown falcon (Falco berigora) and the wedge-tailed eagle (Aquila audax) were the least tolerant raptor species to urban areas.

Birds of prey face lack of habitat, tall buildings, and disturbance by car noise and light at night due to urbanisation.

“As raptors are vital for ecosystem functioning, prioritising feeding and breeding habitat for urban-tolerated raptor species is essential to enable biodiverse urban landscapes,” says Taylor Headland, a PhD student from Flinders University, and co-author of the new study in Nature Scientific Reports.

“While we see evidence of small Australian raptors persisting in urban environments, conservation management initiatives focusing on habitat protection and restoration of wilderness areas need also to focus on the needs of larger-bodied raptor species given the rise in urban expansion and their avoidance of city zones.

The international team of researchers analysed data sourced from the citizen science project eBird, including the raptors’ body mass, nest and habitat types, feeding and migratory status. They integrated this data with a global continuous measure of urbanisation – artificial light at night – to assess the birds’ urban tolerance.

The project demonstrates the value of large-scale, online citizen science aggregation sites. The bird-watching public had provided enough observations the authors were able to analyse over 275,000 species observations for the study. eBird remains open for all new bird sightings, worldwide.

The Cornell Lab of Ornithology and the US Audibon Society launched eBird in 2002, and since then citizen scientists have submitted more than 1.3 billion observations of birds, making it one of the most successful citizen science projects.

“We are concerned for the raptors of Australia and the Southern Hemisphere which are far less studied than those in the Northern Hemisphere so resources such as eBird life are invaluable,” says Headland.