Birds are among the few animals that can navigate the Earth’s magnetic field. But how exactly do they do it? Researchers from the University of Western Ontario in Canada and Bowling Green State University in the United States found that white-throated sparrows can literally turn off their neurological navigation when it is no longer needed.
The study studied white-throated sparrows and found that they can activate a certain part of their brain when they need to migrate, and return it to sleep mode when they rest at stopping points. This “cluster N” region of the brain has previously been identified as important for navigating birds, but it was not clear exactly how it was used in different species, or whether it was activated and deactivated automatically depending on diurnal or seasonal cycles.
“This area of the brain is very important for activating the geomagnetic compass, especially for songbirds when they migrate at night,” said Madeleine Brodbeck of the University of Western Ontario.
The lab analyzed the birds in three groups: daytime, nocturnal rest and nocturnal migratory restlessness. When the birds’ brains were examined, it was found that cluster N activation was associated with migratory restlessness, not day or night restlessness. The more restless the birds were, the more active cluster N neurons were.
This adds to our understanding of how birds and other animals use the planet’s magnetic field to find their way.
“For birds, using the Earth’s magnetic field to know whether they’re moving toward the pole or the equator is obviously really useful for orientation and migration,” Broadbeck says.
The study also reminds us that our cities can interfere with the natural processes going on around us. If we know how animals live, we have a better idea of how to stay away from them or help them find safe passage.
Researchers suggest that future studies could learn much more about the cluster N in the bird’s brain, such as how weather signals or fat reserves might affect its activity.