Each year birds migrate to warmer or cooler climates, depending on the season. How do birds know that they need to do this? How do they know which way is South?
Almost all birds migrate south for the winter. In the fall you can witness their pilgrimage. The reason for this relocation is that during the grueling winter months, food becomes sparse and hard to find. Here is a quick run-down of how birds navigate and get to their tropical havens.
How do they decide which way is south?
Depending on the bird there are different techniques and/or combinations of techniques. For example, some birds follow the stars just like old ship captains, since some birds travel at night to avoid attacks from predators. Other birds use geographical patterns and signs to get to their destination.
These can be anything from rivers to valleys and foothills. Some birds also use the magnetic pull of the earth to find their way south. By utilizing a mineral found in their heads, called magnetite, they can calibrate their homing systems to orient themselves in the right direction.
How do they get south?
All species of birds travel in highly organized flocks. The leader of flock knows best which way to go. When he gets tired, he falls back and lets the second in command, so to speak, take over for awhile. Before any travel, however, there is some preparation to take place in the form of stocking up on food. The birds will eat unusually large quantities of food to stored in
pockets of fat which help to sustain them throughout their journey. Once in the air they try to catch southern bound gusts or gales of wind that will help to push them along in their journey. The more they flap the more energy they exert therefore they find these techniques to save energy.
During spring they return to find a bountiful amount of food in the north until September and its back to the south for vacation again.