Do all birds fly south for the winter?

No, not all birds fly south for the winter. Some birds, such as robins, cardinals, and blue jays, are year-round residents in many parts of the United States. Other birds, such as ducks, geese, and cranes, migrate south for the winter to escape the cold weather and find food. Still other birds, such as hummingbirds, migrate south for the winter but then return north in the spring to breed.