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Why and how do they migrate? Why do migratory birds migrate? It's thought that birds generally migrate to secure food. When winter approaches, it's only natural for birds in the north to head to the south where food is more plentiful. It's thought that birds head north in summer because the hours of sunlight are longer and therefore more time can be spent securing food, meaning that more chicks can be reared. In fact, survey results reveal that in the case of the European Robin, the further north one goes the greater the number of eggs it lays. According to Mr. Ichida, however, "This is a general explanation, and we don't actually know the real reasons. For example, traveling birds fly south from Siberia, but in spite of the fact they'd have a steady supply of food if they stayed in Japan, they then fly all the way to Australia. Arctic Terns breed in the Arctic and spend the summer in the Antarctic. It's not known why, in spite of the fact they could just as well spend the winter somewhere along the way, they go all the way to the Antarctic." So many mysteries remain when it comes to migratory birds. The art of migration: Birds aren't night-blind Recently, a lot of information has come to light concerning the skills of migratory birds. It's known, for example, that many small birds migrate at night to protect themselves from attacks by Eagles, Hawks, and other predators. So what do they use to guide them when they migrate? It seems most people think that birds can't see very well at night (so-called "night-blindness"). In fact this is not true, and it appears that birds actually recognize where they are by using their "eyes" while navigating the sky at night. They use the North Star to guide them. This was verified in an experiment in which migratory birds were taken to a planetarium, where they became lost when the North Star was hidden. Of course, migratory birds rely on more than just visual information. It seems they also utilize such things as geomagnetism, the position of the sunset, and smells, while it's also said route information is built into their genes. It seems that birds that migrate during the daytime use the position of the sun as a reference point and supplement this by using their biological clocks. Also, the fact that certain birds arrive at the same location (lot) every year despite traveling tens of thousands of kilometers suggests they have rather detailed map information. Whatever the case, it's a field in which there is still a lot to be learned, and much is expected of research in the future.

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