Have you ever felt annoyed by your GPS directing you around your own neighbourhood? Well, migratory birds with magnetic sensing abilities could be feeling the same way. It was recently discovered that these avian creatures can literally switch off their neurological navigation aid when it's no longer required. Researchers from the University of Western Ontario and Bowling Green State University conducted a study to investigate how bird brains use the planet's magnetic field to find their way across long distances.
The study focused on white-throated sparrows, and surprisingly found that the birds were able to activate a particular part of their brain, known as "cluster N," only when needed for migration. Researchers also discovered that the cluster N region is associated with migratory restlessness, regardless of day or night activities. The more restless the birds, the more active cluster N neurons appeared to be. Madeleine Brodbeck, a psychology graduate student at the University of Western Ontario who participated in the study said, "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." This discovery is an important step forward in understanding how birds use the planet's magnetic field to navigate and provides crucial insights into how we can minimize our impact on their migratory patterns.
Birds don't just rely on their magnetic compass, but also use cues from the Sun and stars to find their way. Artificial lights and windows in buildings can disrupt their migrations. As Scott MacDougall-Shackleton, a psychologist and biologist at the University of Western Ontario, puts it, "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."
This research is not only fascinating but could also indicate how other animals might use Earth’s magnetic field to navigate, such as sea turtles and bees. There's still much more to learn about the cluster N part of bird brains and how weather cues or fat stores might impact its activity. For now, we are left in awe of how these birds activate their brain to migrate and use the planet's magnetic field, something that is entirely invisible to humans.