Magnetoception: A quantum phenomenon?
The question is, how could man-made signals be interfering with a bird’s ability to measure the orientation of Earth’s magnetic field? One of the things scientists know about magnetoception is that it’s tied to certain types of proteins, called cryptochromes, which is present in many species. These proteins are involved in circadian rhythms in both plants and animals and may play a role in the magnetoception abilities of some species. One theory is that some animals may actually see magnetic fields overlaid on blue light.
One study into cryptochromes attempted to illustrate how the magnetic field might look to a bird flying at altitude. This data, from the Theoretical and Computational Biophysics group at the University of Illinois shows how magnetic field data is overlaid and changed by what the scholars called a “magnetic filter function.”
But the question remains — how does a bird, fruit fly, or other creature sense the weak, low-level magnetic field on Earth? That’s where things get a bit odd. According to the theory, cryptochrome forms a pair of radicals (molecules with a single unpaired electron) when exposed to blue light (in fruit flies) or the Earth’s magnetic field in birds. As weak as the Earth’s magnetic field is, it’s powerful enough to influence the spin state of the unpaired electrons, and it’s thought that the by doing so, it impacts the chemical reactions the cryptochrome causes. (Read: Can animals predict earthquakes, too?)
What this means for the birds of Oldenburg is unclear. Many other research institutions located in urban areas have successfully conducted the same kind of alignment tests that failed in Mouritsen’s lab. With seven years of research, it’s unlikely that Mouritsen’s results are wrong, but they may reflect a local peculiarity in the Earth’s magnetic field or an unusually strong set of EM fields in the 5KHz – 2MHz band interfere locally with bird navigation. This discovery could partly explain why global populations of night-migrating birds have dropped sharply in recent decades, and might shed light on whether different species of bird can sense the magnetic field to a greater or lesser degree. (Read: The wireless spectrum crunch, illustrated.) Research into how some of these capabilities might be extended to humans, who also have cryptochromes in the eye, is ongoing.
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