Electromagnetic 'Smog' Blocks Robins' Internal Compass: Birds Can't Navigate

It turns out that the radio may be impacting birds in unprecedented ways. Scientists have discovered that the magnetic compass of robins fails completely when the birds are exposed to AM radio waveband electromagnetic interference.

"Electrosmog" is human-made electromagnetic noise and below a certain level, it has no impact on biological processes or human health. Yet not it turns out that if this interference is too high, species, such as robins, can suffer.

"In our experiments we were able to document a clear and reproducible effect of human-made electromagnetic fields on a vertebrate," said Henrik Mouritsen, one of the researchers, in a news release. "This interference does not stem from power lines or mobile phone networks. The effects of these weak electromagnetic fields are remarkable: they disrupt the functioning of an entire sensory system in a healthy higher vertebrate."

Scientists knew that birds use a magnetic field to determine their migratory direction. That's why scientists were surprised when robins kept in wooden huts on the Oldenburg University campus were unable to use their internal compasses. That's when researchers decided to investigate a bit further. The scientists covered the wooden huts with sheets of aluminum. This didn't affect the Earth's magnetic field, but did attenuate the time-dependent electromagnetic interference.

"Our measurements of the interferences indicated that we had accidentally discovered a biological system that is sensitive to anthropogenic electromagnetic noise generated by humans in the frequency range up to five megahertz," said Mouritsen in a news release.

The findings reveal how these disruptive effects can greatly impact species. Not only that, but the researchers found that the effects were generated by electromagnetic fields that cover a much broader frequency range at a much lower intensity than previous studies had suggested.

"The effect of anthropogenic electromagnetic noise on bird migration is localized," said Mouritsen in a news release. "However these findings should make us think-both about the survival of migratory birds as well as about the potential effects for human beings, which have yet to be investigated."

The findings are published in the journal Nature.