21/05/2014
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Electromagnetic noise disrupts the magnetic compass orientation in migratory birds

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A new study has found that anthropogenic electromagnetic noise, emitted everywhere that humans use electronic devices, has a negative impact on birds' magnetic compasses. The work, which was carried out using Robin as a study species at the University of Oldenburg, found that the birds could not use their compass when exposed to electromagnetic noise but, when shielded from it, soon regained their navigational abilities.

This is a particularly fascinating development when considering the vagrancy of migratory birds. While the impact of electromagnetic noise is unlikely to be a primary cause of vagrancy, its potential to disrupt migrating birds — whether lost or following a more typical path — is evident if and when they pass through populated areas, where use of electronic devices is high, and there can be no doubt of its potential as a contributing factor. Further study on other migratory species would be useful in establishing the true extent of such problems.

Robin
The study found that Robins suffered failures in their magnetic compasses when exposed to electromagnetic noise (Photo: Mike Lane)

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The abstract of the paper can be read below:

Electromagnetic noise is emitted everywhere humans use electronic devices. For decades, it has been hotly debated whether man-made electric and magnetic fields affect biological processes, including human health. So far, no putative effect of anthropogenic electromagnetic noise at intensities below the guidelines adopted by the World Health Organization has withstood the test of independent replication under truly blinded experimental conditions. No effect has therefore been widely accepted as scientifically proven. Here we show that migratory birds are unable to use their magnetic compass in the presence of urban electromagnetic noise. When European Robins, Erithacus rubecula, were exposed to the background electromagnetic noise present in unscreened wooden huts at the University of Oldenburg campus, they could not orient using their magnetic compass. Their magnetic orientation capabilities reappeared in electrically grounded, aluminium-screened huts, which attenuated electromagnetic noise in the frequency range from 50kHz to 5MHz by approximately two orders of magnitude. When the grounding was removed or when broadband electromagnetic noise was deliberately generated inside the screened and grounded huts, the birds again lost their magnetic orientation capabilities. The disruptive effect of radiofrequency electromagnetic fields is not confined to a narrow frequency band and birds tested far from sources of electromagnetic noise required no screening to orient with their magnetic compass. These fully double-blinded tests document a reproducible effect of anthropogenic electromagnetic noise on the behaviour of an intact vertebrate.

References

Engels S, Schneider N-L, Lefeldt N & 7 others. 2014. Anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird. Nature, doi:10.1038/nature13290.

Written by: Engels et al.