A flock of birds during a migration flight is certainly a spectacular sight. Not all birds migrate, in fact only about 1800 species of birds migrate out of the 10,000 total bird species on Earth. The birds that do have a very good reason for doing so. Amazingly, some species of birds can migrate more than 22,000 km (14,000 miles) each year! If you have ever wondered about the cause of this particular animal behavior, keep reading to find out.
Why do birds migrate?
Scientists do not know all of the reasons that birds migrate, but they have some very good theories to explain this behavior.
Lack of food
The number one reasons for birds migration is believed to be the lack of availability of suitable foods. When the food becomes scarce in one area the birds migrate to an area where more food is available.
Another reason that many birds migrate is because they live in areas that are only suitable areas in certain seasons. Birds often migrate when it becomes cold because the colder weather means they use more energy and the frozen ground restricts the availability of food. Some birds that spend most of the time on water, such as ducks, must migrate because the water freezes during winter.
Another reason that some birds migrate is to breed. Resent research shows that some southern species of birds actually migrate north for the sole purpose of breeding.