Mechanisms of Avian Magnetic Orientation

Among the most fascinating mysteries of life is the interaction between biological systems and the earth’s magnetic field. Although the earth’s magnetism may have an under appreciated role in biological interpretations, it has been most extensively studied in the processes of avian orientation and migration. Many species of bird are known to have behavioral responses to the earth’s and artificial magnetic fields. These responses may be mediated by a number of potential magneto-biochemical processes. The two most commonly investigated include a magnetosensitive magnetite rich region in the upper beak area and a photo/magnetoreception process in the eyes of various bird species. In addition to external magnetic stimuli, recent findings in visually restricted birds have described a hemispherically lateralized interpretation of this information within the brain. Even with these findings, a considerable amount of work is needed to clarify what information is processed and how it is used to create the bird’s magnetic compass. This review focuses these recently published findings as a means to assess this intriguing phenomenon.