Not all birds fly at night when they migrate. Some birds do most of their flying at night, while others get most of their traveling done in the daytime. Scientists believe that stronger birds prefer the day journey and weaker birds feel safer at night.
Most of the daytime fliers are birds that capture their food in the air or must fly great distances to obtain it.
Day fliers include swifts and swallows, which feed as they fly, and herons, geese, ducks, and hawks, all strong fliers that must travel a long way to find food.
Night fliers are generally smaller birds, such as creepers, wrens, thrashers, warblers, tanangers, and sparrows. These night fliers can find food more easily during the daytime when they eat and rest. The dark also offers more protection from enemies.