Why do birds migrate?
Birds migrate mainly to find food and good places to raise their young. They move toward regions with plenty of insects, seeds and daylight in spring, then leave before harsh winters.
In spring, many birds fly to northern regions where long summer days produce a huge supply of insects and fewer predators, which helps them raise chicks. As autumn arrives and food becomes scarce, they fly back to warmer places. About 40 percent of the world's bird species migrate regularly.
Birds use several tools to find their way, including the position of the Sun and stars, Earth's magnetic field, landmarks like coastlines and mountains, and possibly smells. Young birds of some species make their first migration alone, guided by instinct.
Amazing journeys
The Arctic tern makes the longest migration of any animal, traveling between the Arctic and Antarctic every year, which can add up to about 70,000 kilometers or more. A bar-tailed godwit tagged by scientists flew nonstop from Alaska to Tasmania, more than 13,000 kilometers, in 11 days in 2022.
Did You Know?
Before migrating, many birds eat so much that they nearly double their body weight, storing fat as fuel for the journey.