What do birds and our personal gadgets have in common? More than you think, it turns out.
Scientists are fascinated with a bird's ability to align itself with Earth's magnetic fields, and their sensitivity to electromagnetic frequencies. So much so that a specialized experiment was devised with a funnel-shaped cage and blotting paper to mark where the birds tried to escape.
It's a tried-and-true method of observing bird's magnetic senses, but when one researcher moved to the University of Oldenburg in Germany, his experiments went haywire.
“We tried all kinds of things. We changed the light intensity, the size and shape of the funnels, the food the birds were getting, whether they were kept indoors or outdoors,” says Mouritsen. “We tried it all but it didn’t work. I had a very frustrating time.”
So when a post-graduate student suggested that they build a Faraday cage, the researcher was desperate enough to try it. A Faraday cage is a metal cage that is grounded with electricity to intercept and block electrical and electromagnetic fields.
And it worked.
"When the birds were exposed to background electromagnetic noise in their unscreened huts, they flew in random directions. When the Faraday cage was on, their compass started working again. “It was like flipping a switch,” says Mouritsen.
This has nothing to do with wi-fi, mobile phones, or power lines. By deliberately adding electromagnetic fields inside the grounded huts, the team showed that they were sensitive to frequencies between 2 kilohertz and 5 megahertz. With that range, the culprits are likely to be either AM radio signals or fields produced by electronic equipment in the university, although it’s hard to narrow the source down any further."
So, our personal gadgets are safe for now, but as scientists continue to experiment we have to make some adjustments.