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article imageToday's electronics may send migrating birds off course

By Martin Laine     May 8, 2014 in Science
The explosive growth in electronics — everything from smartphones to AM radio signals — and the electromagnetic radiation they create could disrupt the flight paths of migratory birds, especially over urban areas, where the concentration is heaviest.
This discovery came somewhat by accident in the course of a different research project, according to an article in Nature.
It has long been known that many species of migrating birds use the earth’s magnetic fields to orient themselves. What is not known is just how this biophysical phenomenon, this internal compass, works. Henrik Mouritsen had been conducting research to find out in what part of the bird’s brain this information was processed.
His experiments involved keeping European robins in wooden huts, effectively shutting out the sun, stars, or any other visual cues the birds might use, so that they could observe how the birds would orient themselves. In 2002, he moved his experiments to the University of Oldenburg, a city of 160,000 people.
Here, under the same conditions as out in the countryside, the birds could not orient themselves.
“I tried all kinds of stuff to make it work, but I couldn’t,” Mouritsen said. “Until one day we screened the wooden hut with aluminum.”
After covering the huts with aluminum plates and grounding them, the electromagnetic radiation was reduced significantly, and the birds were able to orient themselves normally. When the ground was disconnected, the radiation level rose and they were once again disoriented.
Mouritsen and his students repeated the process over the course next seven years to make sure the observations were valid.
“We wanted to make sure that we could really document that what we were seeing was real,” Mouritsen said.
However, another bird navigation researcher, also working in Germany, has not seen the same phenomenon.
“We never used any shielding, and our birds were perfectly oriented,” said Roswitha Wittschko at the University of Frankfort. “This is a really surprising thing for me.”
Still other researchers have noticed a similar phenomenon in other animals.
“These effects are real,” said John Phillips, a sensory biologist at Virginia Tech in Blacksburg, Va. He has noticed in mice and newts, in experiments involving navigation and spatial memory.
As for Mouritsen, he plans to continue his research into the workings of a bird’s inner compass.
More about Migration, Electromagnetic radiation, internal compass
 
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