Does the hawk take flight by your wisdom
and spread its wings toward the south?
Job 39: 26

The answer to the question in this ancient poem is no, humans can't write itineraries for avian species. But recent discoveries in quantum biology reveal surprising insights into bird migration tools. That little zebra finch is using quantum mechanics to get around: specifically, quantum entanglement.

Why Quantum Physicists Have to Believe Six Impossible Things Before Breakfast

Quantum mechanics makes a lot of people's heads hurt, because parts of it are counterintuitive. So let's try to explain quantum entanglement without resort to headache powders. It's all about a weird thing that subatomic particles can do.

Entanglement happens when two subatomic particles are generated at the same time. They are then paired in such as way that one particle can't be described without affecting the other. In other words, if you look at a subatomic particle and determine its spin to be 'up', its twin will automatically be 'down'. Apparently, just looking at them will make the particles flip spins. These sneaky particles do this without any visible means of communication and no matter how far apart they are. This seems uncanny, even to physicists, and leads to widespread outrage and the general feeling that this sort of thing ought not to be allowed. Nonetheless, it is so: scientists are sure about this. But what does this have to do with birds?

Bird's Eye Views

Birds in their billions fly around the planet every year, moving from breeding grounds to wintering grounds, maximising their food-gathering potential and delighting bird watchers. As thrilled as we are to see the buzzards returning to Hinckley, Ohio, or the winter birds of the Niagara Gorge, we often look at them in puzzlement. How do they do that? we wonder. Quantum biologists think they know: it's all in the eyes.

Birds' eyes have cryptochrome proteins (from Greek κρυπτος   χρωμα meaning 'hidden colour'). These are sensitive to blue light. In birds, as well as other animals and even plants, they are involved in circadian rhythms¹. They are also implicated in the way some organisms sense magnetic fields². Birds use Earth's magnetic field to navigate back-and-forth to their favourite spots. They are remarkably accurate. Researchers now think the birds' cryptochrome proteins are helping them figure out when to move house, and where to go. It's like birdie Satnav.

The calculations involved are complicated, involve Greek letters and such, and will probably give the layperson another headache, but the bottom line is that the researchers believe the cryptochrome protein navigation is operating on a quantum level. If you care to look at the pictures – or if you're really clever and can follow all the references to 'anisotropic' and 'isotropic' values – just drop in on the discussion at Hiscock, Worster, et al, 'The Quantum Needle of the Avian Magnetic Compass', PNAS (Proceedings of the National Academy of Sciences of the United States of America), first published 4 April, 2016.

So, as you welcome your spring or winter visitors to the bird feeder, remember to ask them if know they're annoying Professor Einstein³.