Electromagnetic noise can disrupt birds’ internal compass

Washington Post : European robins have been shown to have difficulty orienting themselves because of interference caused by electronics and AM radio signals. Such manmade electromagnetic noise could significantly affect birds’ migratory patterns, according to a paper published in Nature by Henrik Mouritsen of the University of Oldenburg in Germany and colleagues. To study the birds’ internal compass, the researchers kept them in wooden huts to prevent them from relying on the Sun and the stars. In rural areas, the birds had no trouble orienting themselves in their proper migratory direction, but in the city of Oldenburg, they could not. Through a series of tests, the researchers narrowed down the problem to confusion caused by ambient electromagnetic noise. Only after the researchers damped the noise by covering the huts with electrically grounded aluminum screening could the birds orient themselves properly. Although the phenomenon has been noted by other researchers, more work is needed to show that it occurs on a global scale and to better understand the precise workings of birds’ magnetic sense.