Why do birds migrate from north to south?

Most birds that migrate annually migrate south in the fall to spend the winter in warmer climates. For many birds, their bodies are not adapted to handle the cold weather and lack of food that winter tends to bring to most places. The birds that migrate south for the winter migrate north again in the spring because the weather is normally warmer in the spring and summer. The warmer temperatures make it easier for birds to breed and raise young without potentially losing their babies to the cold weather.