A team of researchers from the University of Oldenburg, Germany, have found that the electromagnetic fields produced when we connect power plugs to the mains, and AM radio signals, are capable of playing havoc with birds’ natural sat nav.
How birds are able to use magnetic fields at all isn’t very well understood, but it’s believed they may be able to navigate their way around the world with help from receptors in their eyes. These cryptochromes, as they are called, enable them to sense the Earth’s magnetic field, just like a biological compass.
The scientists, led by Professor Henrik Mouritsen, discovered that when European robins were exposed to weak electromagnetic fields of a certain frequency (like those created when electronic devices are plugged in), they lost all sense of direction.
“The basic experiment we do in bird-navigation research is that we put birds into an orientation cage,” Professor Mouritsen explained. “They are so eager to migrate, that they will jump in the direction in which they want to fly, and if you turn a static magnetic field in the horizontal plane they will start to jump in a different direction.”
This is likely to affect migratory birds as they fly over towns and cities, where there are large concentrations of homes and businesses that constantly use electronics.
However, despite being unable to effectively sense the Earth’s magnetic field in such a situation, these birds could still rely on their other abilities to find their way.
“The birds wouldn’t be completely lost because they have three different compasses: a star compass, a Sun compass and a magnetic compass,” says Professor Mouritsen “These work independently of one another. As long as it is clear, they should be fine with their sunset compass or star compass.”