The migration of birds has fascinated man since the very beginning of history. Did you know that Homer wrote about it in 1000 B.C.; it’s mentioned in the Bible; and the great Greek philosopher, Aristotle, studied the question?

And yet, so many thousands of years later, we still don’t have the complete answers to the fascinating phenomenon of the migration of birds. By this migration, we mean the movement of birds south in the fall and north in the spring, or moving from lowlands to highlands, or from the interior to the seacoasts.

We can have a pretty good idea as to why it’s good for the birds to migrate. For example, they go to warmer climates because some of them couldn’t survive winter conditions. Those birds that feed on certain insects, or small rodents, wouldn’t find any food in winter. Oddly enough, temperature alone would not make most birds migrate. Did you know that your canary could probably survive outside in the winter in temperatures 45 degrees below zero, centigrade, if it had enough food?

Whatever the reason for the migration (and there are many), how do birds know when it’s time to take off on their tong flights? Well, we know that they migrate quite punctually every year when the season is changing. And what is the surest, unmistakable clue to the fact that the season is changing? The length of the day! It is believed that birds can tell when the days get shorter (and longer in the spring), and this is the best “alarm clock” they have to tell them to get along!

Since birds breed in the summer, this is also connected with migration. Only in this case, it’s migration northward. Certain glands in the bird begin to secrete chemicals that have to do with breeding. This happens in the spring. The bird feels the need to breed and heads north where it will be summer.

So the change in the length of days and the disappearance of food tell the bird to head to warmer places. And the breeding instinct in the spring tells them to head north. There are many other factors involved, of course, and many things we still don’t understand, but these are certainly among the chief clues to bird migration.