The annual travel plans of birds along Australia's east coast have been revealed for the first time, using the same tool that tracks the weather; According to development experts, it could have “profound” implications for conservation as more wind farms are built.
Scientists have used weather radar to show that bird migration across eastern Australia occurs in structured patterns. While many Australian bird species are known to be seasonally migratory, scientists did not know to what extent a distinct system existed.
New research, published in the journal. Current Biology used years of radar data to determine two pulses of bird migration along the East Coast: northward from January to June and southward from July to December.
In autumn, there were an media of 60,000 migratory birds per kilometer each year, researchers found using data from 2018 to 2022.
Shi Xu, lead author of the study and a PhD candidate at the University of Queensland, said weather radar can “observe how birds, insects or bats fly in the air and move in airspace.”
“It quantifies the amount of movement that occurs in the area, just like it measures the amount of rain.”
The team used complex mathematical models to remove the movement of insects and flying foxes from the data.
Study co-author Professor Richard Fuller, also from the University of Queensland, said: “There is a wave of migration coming out of Conquista and Tasmania and up the east coast, to the southern border of the tropics.”
Understanding bird migration routes in Australia was a “tremendously important and urgent issue” in the context of wind farm development, Fuller said.
“Queensland and Tasmania are intimately connected by birds that move between those places and across many of the landscapes in between, so we need to unite a conservation effort.”
Unlike bird migration in the Northern Hemisphere, which is predominantly nocturnal, the researchers also found significant levels of diurnal migration, which they say may be unique to Australia.
BirdLife Australia national public affairs director Sean Dooley, who was not involved in the study, said the research showed variability in the timing and direction of migration, which appeared to be driven in part by different weather conditions between seasons.
He added that the “promising field of study” may have profound implications for renewable developments along migratory routes, including in the Great Dividing Range and coastal areas such as Bass Strait.
While weather radar can provide information on the number of birds flying, it cannot identify individual species. Next, the researchers plan to triangulate the radar data with sightings recorded by citizen scientists in bird-watching apps, to better understand which species are migrating and where.
This information could have implications for threatened birds such as the orange-bellied parrot and swift parrot, Dooley said. “More detailed studies could help protect other partially migratory species on the continent, such as the critically endangered regent honeycreeper,” he added.