For thousands of years, humans have used birds as a reliable form of communication, with the earliest known use of pigeons for delivering messages being in ancient Egypt, around 1350 BCE. For as long as we’ve domesticated them, we’ve wondered how they can fly so far and not get lost, as even training can’t prepare them for what happens if they get off course. Early scientists, specifically zoologist Camille Viguier, thought that maybe birds (and other vertebrates) used the Earth’s magnetic field to help them navigate, much like some marine animals.
Recent research at the Ludwig Maximilian University of Munich has discovered that Viguier was, in fact, onto something extraordinary, as they have found that birds, specifically pigeons, might be able to sense magnetic fields via electric currents. After Viguier’s papers were unearthed by a graduate student Gregory Nordmann, neuroscientist David Keays, and his colleagues started looking deeper into Viguier’s work and started investigating pigeons’ semicircular canals for links to whether they could sense the Earth’s magnetic fields. What his work showed opened up a whole world of research into the brains of birds and other animals, such as insects and turtles, who have similar abilities. They are also wondering and researching if the inner ear is connected to this phenomenon, and have done multiple experiments to see how their brain activity works with magnetic fields. There are multiple other animals known for using magnetic fields to travel and “see”, such as sharks, whose electroreceptors are in their skin, or skates (a type of fish that is related to the manta ray), whose electric organ is in their tails. These animals have helped the research into the pigeon’s magnetic sense, and the team has even found that pigeons have a similar genome modification to those animals.
Kaeys’ team has found that the magnetic fields trigger pigeons’ vestibular system, which is basically the system in their body that helps them balance and create a sense of spatial orientation, similar to humans (without the magnetic sense). The semicircular canals mentioned are part of that system. Some hypotheses for how birds sense magnetic fields are that they can simply “see” the magnetic field through their retina cells, or that they might have tiny iron oxide particles on their beaks that act as compass needles.
Kaeys’ team has also done experiments that showed that light isn’t necessary for them to interpret the magnetic stimuli they’re getting, which means day or night, they know where they’re going with complete accuracy. Different parts of the brain are activated in the light or dark, though, for reasons still unknown. They have stated that even a pigeon’s head bobbing could help them provide their brain with information about the “x, y, z” components of the magnetic field.
This all shows that pigeons, birds remembered affectionately as “sky rats,” have much more going on in their brains than previously thought, showing just how complicated they truly are. Scientists are still searching for what links the information coming into their brain into tangible information that helps them orient themselves and find their way, and are hoping future research advances this field exponentially.
