Not all birds migrate, but a lot of them do, two of the best known British migrating birds being the swallow and the house martin, which fly south in the autumn to spend the winter in parts of Africa. The reason they do this is because of the need for food, of which there is a great shortage in northern Europe during the winter – these birds eat mainly insects which die or hibernate in winter.
So why doesn’t the swallow stay in Africa all year round? The reason is that it breeds in Europe rather than in Africa. This also the case when fish such as salmon travel each year to places where they feed.
It isn’t only European birds which fly south. North American birds fly south in the winter too. In the southern hemisphere, when winter takes place at the same time as European summer, Australian birds fly to places like Malaysia to escape the winter. They are there from April to September, and between October and March Malaysia sees northern hemisphere birds like cuckoos and plovers arriving to spend the European winter months there too. So Malaysia has regular colony of foreign birds at all times of the year. It makes you wonder what happens to all the native birds of Malaysia when all these visitors arrive, doesn’t it? Thy must never have the place to themselves!