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.
The theory that navigational skills in some birds may be influenced by iron particles in their beaks reacting to the magnetic field of the earth, has recently been refuted by scientists at Vienna’s Institute of Molecular Pathology. Acknowledging that the new discovery was somewhat disappointing, molecular biologist David Keays noted that the mystery of how animals detect magnetic fields had become even more mysterious.
Using 3D scanners on slivers of pigeon beak, researchers found that the particles which had previously been thought to react with the earth’s magnetic field were in fact macrophages with normal amounts of organic iron to protect the birds from infection. These cells have no ability to produce electric signals to communicate with brain cells and are therefore unable to influence the pigeon’s behavior. These same cells were also found in other parts of the bird’s body and are found in other animals, particularly in the spleen, lungs, and skin, where they play an essential role in recycling iron from red blood cells and fight against infection. The findings were confirmed by scientists from the University of Western Australia – Jeremy Shaw and Martin Saunders – who were also working on the study.
Keays was reported as saying that the new discovery should not be seen as a set-back as it puts scientists on the right path to finding magnetic cells. The general consensus remains that birds, and a significant number of other animals, detect the magnetic field of the earth and use it for navigation. So it stands to reason that they must have cells facilitating this, although in the case of birds, it has been suggested they may make use of landmarks or sunlight for navigation as well.
Scientists will continue in their quest to understand how migratory birds interact with the earth’s magnetic fields, with the hope of linking their findings to other species with homing habits, including sea turtles, rainbow trout and bees. Although the project has its challenges, Keays believes that learning how nature detects magnetic fields could lead to the creation of artificial magnetoreceptors with the potential of treating human medical conditions, particularly relating to the brain.
Nature not only surrounds us with sheer beauty but also offers an abundance of fascinating new discoveries that continue to amaze us. Just when we think we know everything about an animal or bird, they seem to prove us wrong. More recently, birds have revealed that crests and beards are not merely used for finding a mate, but serve a greater purpose, allowing them to explore their surroundings as well. Research on birds, such as the auklet, has opened up a new door into the world of birds and their feathers.
Professor Ian Jones, St John’s Memorial University, and Dr Sampath Seneviratne, University of British Columbia, shared their insights and suspicions that certain feathers on a bird’s body could serve to heighten the sense of touch. When looking at birds, such as the auklet, which have intricate feathers on their heads, scientists found that by putting them through a simple navigational test, much was revealed in regard to the role that crests and head feathers play. Using a dark maze, as this breed tends to breed in dark crevices, it was found that when the birds navigated the test, they succeeded in completing the maze with less difficulty than when researchers flattened their head feathers. It was also noted that in general, if birds have ornamental feathering, they tend to be birds that are active at night.
Researchers then looked at bird species that do not feature elaborate feathering, including pheasants, kingfishers, parrots, penguins and owls. They suggest that even if some birds do not have crests and rectal bristles, longer wing feathers may also serve as a means of touch. Many birds use their feathers and coloring to show off their abilities and to either startle or camouflage themselves from their predators, but there is good reason to believe that feathers have various other functions that we have not been aware of until now. The new insight into facial feathers and flamboyant feathering could lead to further studies,to confirm these findings and the preliminary research. This use of their feathers for touch and orientation has revealed a more complex side to birds, and will have us gazing a little more intently whenever we look at these colorful creatures of the skies.
For decades scientists have been puzzling over an intriguing wildlife mystery: how is it that birds navigate? Each year thousands of these feathered creatures make massive journeys halfway around the globe – yet exactly how they find their way to their destinations each year just boggles the mind.