Now that winter is on its way out and the weather is starting to get warmer, it will soon be time for many animals to begin migrating. There is actually a term for the restlessness animals experience when it comes time to migrate. Zugunruhe is a German term, which literally translates to “migration anxiety”. As the seasons change, birds will become more active, flitting around and jumping from branch to branch. This is especially evident when they are kept in captivity. They will fly about their enclosures or sit on a perch and flap their wings.
These Northern flickers were difficult to photograph because they were way at the top of a tall tree. These birds live in the area year-round, but I thought I’d share this photo I took recently.
Recent studies have shown that once they do begin migrating, they are able to sense the Earth’s magnetic field and use it for navigation. In 2014, scientists at the University of Oldenburg in Germany published a study about how sensitive birds were to magnetic fields. In these experiments, they captured robins who were in the middle of migration and placed them in a screened enclosure. These robins would actively orient themselves towards the north end of the cage, as that is the direction they wanted to go. Then the scientists would place a Faraday cage around the enclosure. A Faraday cage blocks radiation, including magnetic fields. When this was done, the robins lost all sense of direction, and spread out towards all directions. Removing the Faraday cage then caused them to orient northwards again. And when the researchers applied an artificial magnetic field pointing in a different direction, the robins faced that way instead.
It is thought that birds have special proteins in their eyes which can react to the direction a magnetic field is pointing. This allows birds to literally see magnetic fields. It’s fascinating to think of how evolution can allow even tiny quantum effects to play a big role in life.
So the next time you see a flock or birds flying somewhere, remember: they don’t need to stop and ask for directions. Their built-in GPS is good enough.
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