As you will see during the migrations this fall and spring, there are countless cases where an animal's very survival depends on being at the right place at the right time. While the underlying science of biological clocks is complicated and not fully understood we do know that animals set their master clocks according to the world's most dependable time keeper-the sun. The annual cyclical changes in photoperiod provide a dependable measure of time. You can also find useful information at the following on the World Wide Web. Migration is the seasonal movement of animals from one habitat to another.
Animals migrate between their wintering and breeding habitats.
Some creatures that you would recognize that migrate are whales, fish, butterflies, turtles, geese, robins and caribou. Some animals travel incredible distances on these annual journeys. Migrating animals follow established migratory routes. In Europe, some migration routes are oriented more east west. Most long distance migrant birds fly at night.