Sweden, May 8: Every year birds from more than 4000 species migrate to different places. Researchers have been able to track the migration paths of larger birds such as geese but it’s challenging to fit small songbirds (the birds that make noise while flying) with the tracking.
To track the warblers, a group of songbirds which are about half the size of an American robin, Sjöberg, Hasselquist, and colleagues fitted them with small, unique data loggers weighing about 1.2gms which are small backpacks that can monitor when, how high, and where the warblers fly on their semiannual journeys between Sweden and Africa. The researchers put the backpacks on 63 birds and retrieved useful data from 14. As expected, the migrants usually spent their nights flying and rested during the day. But most birds when they hit a water or desert at evenings kept flying as the sun rose, climbing high into the sky. They found that one bird was airborne for more than 32 hours. Instead of staying at typical altitudes of less than 2000 meters, some birds soared higher than 6000 meters!! Such altitudes can be stressful but they can avoid over heating due to sun’s radiation. At 6000 meters, oxygen is scarce and the temperature is below freezing. Somehow these birds are able to cope with this differences and reach their destination.
