Researchers revealed that migratory birds could ignore or process magnetic information, similar to how humans listen to music they enjoy and tune out if they don’t.
The Earth’s magnetic field shields the planet and its inhabitants from the harmful plasma and cosmic rays emitted by the Sun. However, certain creatures use this magnetic field for navigation, much like a GPS, and can turn it on and off.
Researchers from Bowling Green State University in the United States and the University of Western Ontario in Canada uncovered a brain region known as cluster N that is used by birds to detect and process the magnetic field of the Earth.
According to a study published in the European Journal of Neuroscience, Cluster N is engaged only when birds want to migrate and likely engage in their magnetic compass.
Magnetically sensitive proteins are used by birds
Previous research has revealed that birds prefer to use magnetically sensitive proteins known as cryptochromes, which are found in their retinas and provide signaling and sensing capabilities, assisting the birds in navigating the great distances they travel while migrating.
The team, led by psychology Ph.D. candidate Madeleine Brodbeck, researched white-throated sparrows and discovered that they activated cluster N at night when they were driven to migrate to different regions and switched it off during the day when they were resting.
“This brain region is super important for activating the geomagnetic compass, especially for songbirds when they migrate at night. Almost all previous work on this specific brain function was done at one lab in Europe, so it was great to replicate it in a North American bird like the white-throated sparrow,” Brodbeck said.
The magnetic field, which is formed by the flow of molten iron in the planet’s inner core and extends into space, is invisible to humans. However, that process is present in the brains of some animals, allowing them to recognize it when traveling large distances. “If we want to understand bird migration or how other animals move from one place to another, we need to know how they do it. And more importantly, we need to know what we’re doing, as humans, that might influence them,” stated MacDougall-Shackleton.
According to the experts, birds do not generally use the magnetic field as a cue but instead look to the stars and the sun. “This type of basic research informs us and lets us know the full suite of ways that animals perceive the world when they’re migrating and what we as humans need to do to minimize our impact,” MacDougall-Shackleton stated.