When the sun has set and we are getting ready for bed, we have heard geese honking. They fly overhead and land in a marshy part of the lake. Then again in the morning, we have woken up to the sound of honking. Then the large group takes off. Where did these geese come from and where are they going?
To answer these questions, we need to learn about migration. Migration means the movement of a group of animals from one place to another. Usually the migration is seasonal. Here in the United States, we see certain animals heading south for the winter. Then they head back north for the summer. That means fall and spring are busy times for these animals. Many birds migrate. The geese we have been hearing are Canada geese heading south.
Some animals travel long distances when they migrate. Others travel a bit, but they don’t go very far. Some animals travel from one specific place to another. When all members of a species move, that is called a complete migration. Loons make a complete migration. They spend summers here and winters in the Gulf of Mexico. For some animals, not all members of a species migrate. This is called a partial migration. When a group of animals moves from place to place, that is called nomadic migration. A herd of bison wandering around on the plains is a good example of nomadic migration.
Birds aren’t the only type of animal that migrate. Birds, mammals, reptiles, amphibians, fish and insects migrate. Did you know that monarch butterflies migrate? They fly all the way to Mexico for the winter.
Why do you think animals migrate? All animals need food, water, and shelter to survive. When the seasons change, the habitat changes. Loons spend all summer swimming around the lakes in the Boundary Waters Canoe Area Wilderness. They fly from lake to lake. They catch fish in the water. They make nests and hatch their eggs on shore. When the winter comes, the lakes will be covered in ice. They need water to take off and land. They need access to the water to catch fish to eat too. Food is the most important reason that animals migrate. Animals migrate to avoid extreme heat or cold. As in the case of the loon, the temperature changes affect an animal’s food source.
Sometimes when animals migrate, the way they look changes. In the summer loons are black with white spots. When they head south for the winter, they are mostly gray. In fact, for a long time scientists thought that loons were two different species because they looked and even sounded different between summer and winter.
How do you think the animals find their way when they migrate? How does a salmon know which stream to swim up to spawn? How does a loon pair return to the same lake every summer? This is still a mystery in many ways, but scientists have found some clues. Many animals that migrate during the day use the sun as a guide. Birds that migrate at night use the stars to know where they are. There are even more complex ways that animals navigate. I hope this helps you understand animal migration. There are so many more interesting things you can learn about it too. Follow these links to learn more.
Student Response Worksheets–Be sure to subscribe to our newsletter to receive the answer documents for each week’s worksheets