Why do birds migrate?

As fall and winter bring colder temperatures, insects and other foods become scarce. Most insect-eating birds head south to find food.

Some species of birds spend the winter as close as the southern U.S. or as far as South America . Most insect-eating birds travel to Mexico, Central America and the Caribbean. These birds actually spend more time on their tropical wintering grounds than they do on U.S. or Canadian breeding grounds.

As spring arrives the birds return north. But why not stay in the warm tropics where food is available year round? The main reason is the massive burst of emerging insects in the northern spring and the longer days in which to forage for food. Migrant birds can produce more young under these conditions than similar species in the tropics. There are also fewer predators, parasites, and diseases in temperate regions. More young can be produced and survive to adulthood, making migration worth the cost.

Show All Answers

1. Why do birds migrate?
2. What are flyways?
3. How did migration originate?