Migratory songbirds lose their sense of direction in large urban areas.
Songbirds are restless creatures, and scientists have learned to take advantage of that trait to study their migration. In one famous experiment, researchers place a bird in a cage equipped with sensors. When night falls, the bird jumps in the direction in which it would normally migrate, allowing researchers to determine where it would like to go. But in 2004, in a German lab at the University of Oldenburg, the classic experiment failed miserably. The European robins that the researchers were using simply wouldn't orient themselves in a single direction. "We tried to change the food the birds were getting, the light, the cages — just about anything," recalls biologist Henrik Mouritsen. "Nothing had any effect."
For the next three years, Mouritsen and his team tried to figure out why the robins weren't orienting. Nothing they tried seemed to work, until one of the scientists made a suggestion: maybe they should block the electromagnetic noise emanating from the electronics on campus, just to see. That night, the researchers covered the cages with aluminum screens and, against all odds, the birds started jumping again. This was the moment that the researchers realized what no one had ever considered: the invisible lines of force that electronics constantly emit around us were actually disrupting the orientation capabilities of small migratory songbirds.
"We are absolutely sure that the effect is real," Mouritsen says. And the intensities that are affecting the birds are "1,000 times below the World Health Organization guidelines."Today, the researcher speaks with authority, but back in 2007, Mouritsen was more than a little skeptical. "My immediate reaction was that this is highly unlikely to be the reason." So the scientists did a number of follow-up experiments — six years' worth — to confirm the results that were finally published today in the journal Nature.
Unfortunately, these experiments didn't determine which electronics are to blame. The disruption, Mouritsen says, could come from "basically anything you put into a plug." But the effect is only present in large urban or industrial areas, and around university campuses — locations in which humans tend to use a large number of electronics at once.
Written By: Arielle Duhaime-Ross
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