很多候鸟依靠地球磁场掌握方向，尽管它们是用什么机制来探测这一极弱磁场的仍不清楚。Henrik Mouritsen及同事发现，2004年秋和2006年秋之间在奥尔登堡大学校园内的木屋中测试的夜间迁移的鸣鸟(欧洲知更鸟)似乎无法找到正确的迁徙方向。在这一意外发现之后，他们进行了对照试验，以弄清到底发生了什么。他们发现，当知更鸟暴露于频率在大约20kz 和20MHz之间的低水平AM电磁噪音(这是消费电气和电子设备通常产生的那种噪音)时，它们便会失去利用地球磁场的能力。有趣的是，这种电磁噪音的磁成分比世界卫生组织(WHO)当前纲要中采用的暴露下限低1000倍，但它却能扰乱一种高等脊椎动物的整个感觉系统。当将这些实验鸟在2 kHz到5 MHz的频率范围内与电磁噪音屏蔽开来时，或在一个农村环境中对其进行测试时，它们会重新获得用地球磁场来定向的能力。
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 50 kHz to 5 MHz 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.