Scientists from the United States and Germany claim that they have managed to disprove the hypothesis that migratory birds are oriented in space with the help of particles of magnetite, hidden in their beaks. New experiments suggest that birds may follow the changes of the magnetic field by means of the organs of vision.
The hypothesis in question, five years ago, put forward at the Institute of Zoology at the University of Frankfurt. They found in the tissues of the beak of homing pigeons tiny particles of magnetite, elongated along the nerve fibers. Hence, it has been suggested that the crossing of the magnetic field, these particles affect the undiscovered nerve receptors that transmit the signals to the brain. No one could say exactly how this interaction takes place, however, many experts believed that the key to unlocking the wonderful ability of birds to find their way during the flight has already been found thousands of kilometers.
And now the key checked and culled California physics and experts in animal behavior from the same University of Frankfurt, the Johann Wolfgang Goethe University and Virginia Polytechnic Institute. They observed the behavior of robins, planted in cone-shaped cells are placed inside the solenoid, which serves an alternating magnetic field. These experiments were conducted during the spring migration season, when the birds if they were on the loose, was supposed to come back from warm to Europe. However, in the cells was not enough space for a free flight, but the robins had the opportunity to not only walk and run, but the flutter from place to place. When the imposed field was parallel to the power lines connecting the magnetic north with the south, the birds were moving mostly along the meridian from south to north. The situation is completely changed when the vector of the alternating field was marked angle with the vector of Terrestrial Magnetism (specifically, 24 and 48 degrees). In such circumstances, the birds lost their orientation and their movements become erratic.
But what has this magnetitnaya hypothesis? The fact is that the experimenters used a high-frequency field, which could not affect the arrangement of the particles of magnetite in their beaks of robins. Therefore, Thorsten Ritz and his colleagues concluded that these fields and the magnetic field of the planet is likely to affect the photochemical reactions taking place in the retina of birds. It is possible that a bird in a sense, see the earth's magnetism and thus do not go astray during their seasonal migrations. However, while it is also just a hypothesis.
Battery News, 19.05.2004 15:05
Source: Nature News