This ability – known as magnetoreception – isn’t unique to robins. It’s been found in many other birds, sharks and rays, salmon and trout, turtles, bats, ants and bees, and possibly cows, deer and foxes. But despite more than 50 years of research, the details of the magnetic sense are still elusive.

Unlike light, sounds or tastes, which come and go, the Earth’s magnetic field is always ‘on’. To study how animals sense it, scientists first have to cancel it out using magnetic coils, and set up their own artificial field.  The field also pervades the entire body, so there’s no obvious opening, like an eye socket or ear canal, where a magnetic sensor would most likely lie.

In birds – the