Until now, bird migration on Australia's east coast was still a bit unclear to experts. We knew that many species were seasonal, but little did we know that there was a distinct system that birds follow to migrate each year.
A new study published in the journal Current Biology reveals that there are two waves of migration each year on the East Coast. From January to June, the birds move north while they head south from July to December.
Weather radar reveals secrets of migratory birds in Australia
To arrive at this conclusion, the researchers collected and analyzed weather radar data. These radars are used to detect precipitation and measure its intensity in real time, but they can also detect the movement of flying animals.
As Shi Xu, lead author of the study and a doctoral student at the University of Queensland, explains, a weather radar can “observe how birds, insects or bats take flight and move through airspaces.” .
However, radars cannot identify individual birds in order to count them. “They quantify the movement that occurs in the area, just as they measure the amount of precipitation,” specifies the author of the study.
Wind farms could hamper Australian bird migration
On average, researchers estimate that there have been 60,000 migratory birds per kilometer each year in the fall. They used complex numerical modeling to eliminate the movements of insects and bats recorded by radar.
The radar data thus revealed that there is indeed “a wave of migration which leaves Victoria and Tasmania and goes up the east coast, to the southern border of the tropics”, explains Professor Richard Fuller, co-author of the study.
The specificities of the Australian bird migration system are all the more important as the regions concerned are in full development of wind farms.
“Queensland and Tasmania are intimately linked by the birds that move between these places and across many landscapes between them, so we need to lead a joint conservation effort,” adds the professor.
A diurnal migration that could be unique to Australia
In addition, weather radar data also made it possible to discover unexpected behavior of migratory birds. Compared to species in the northern hemisphere which migrate at night, many Australian birds migrate during the day. This diurnal migration may well be unique to Australia.
Finally, researchers have also noticed that the migration of birds from the east coast can vary depending on the climatic conditions of the seasons. Birds do not always head in the same direction at the same time.
Source: The Guardian
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