While the navigational skills of birds remain largely unexplained, the theory that they use the magnetic field of the earth to some degree to map their positions is generally accepted. The magnetic field of the earth is weakest at the equator, becoming stronger toward the north and south poles. This change in magnetic strength may give birds an estimate of their latitude while in flight. This amazing ability to navigate is especially evident in homing pigeons which are able to find their way home over distances of as much as 1,100 miles (1,800 km) with unwavering accuracy. Research has revealed that pigeons have a significant number of iron particles on top of their beaks, which act as a natural compass to guide them, along with visual landmarks and olfactory markers.
It has long been debated whether manmade electromagnetic fields are detrimental to human health, and conservationists share this concern when it comes to animals, particularly migratory birds. A recent study by scientists from Oldenburg University in Germany has found that manmade electromagnetic fields are confusing migrating robins, which also rely on the earth’s magnetic field for navigation. The study was prompted by observations made seven years ago when it was noted that European robins (Erithacus rubecula) stopping over at the university campus during their annual migration appeared confused. Over the next seven years, experiments were carried out by alternatively blocking and unblocking electromagnetic radiation and observing the behavior of the birds. It became clear that when the birds were exposed to the manmade electromagnetic forces they became disoriented. It is worth noting that birds are susceptible to far lower levels than those deemed safe for humans as set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) which mandates guidelines for all types of electrical devices, including power lines and mobile phones.
What this means for both animals and humans will no doubt remain a matter for debate as more research is carried out to understand the impact of modern technology on the natural world.