Why do some birds migrate?

The story behind the answer

Birds migrate primarily to find food and better conditions. As seasons shift, insects vanish, fruits dwindle, and waters freeze; moving to milder regions lets birds keep feeding and save energy, then return to breed where spring offers a burst of resources and long daylight.

Remember it as “migration = meals and milder weather.” Day length and temperature trigger hormones that start migration, and birds navigate with landmarks, stars, smells, and even Earth’s magnetic field—navigation tools, not the goal. Predators and competition play roles, but the main payoff is higher survival and more chicks when travel is timed to food peaks like insect hatches or fish runs. Think swallows chasing flying insects, warblers following spring blooms, and shorebirds tracking coastal invertebrate surges.