In countries like England, France and North America, when the weather gets very cold in winter, rich people move to warm climates. We have seen rich people move to hill resorts and live there when the weather gets hot in summer.
The birds and animals also move from one place to another when the climate changes. It is one of the mysteries of nature that birds are able to travel thousands of kilometers and come back to their original resting places at regular intervals.
During September and November flocks of birds come from somewhere and then go away.
Bird watchers after years of patient observation and study of these migrating birds have concluded that there is a regular and systematic about their behaviour. People used to think that small birds such as Swallows, Nightingales and Cuckoos went to sleep during the winter; but now it is known that they go to warm countries.
Why do birds migrate? They are not directly affected by the cold because of their feather covering and warm blood, but in winter getting food is not easy.
Snow lies thick on the ground in winter and even lakes and rivers are frozen over. The weather is such that birds will not be able to catch either insects or fish. If they do not migrate, they will perish. As the nights are short the time available for searching for food is short, So, they have to fly over to warm places.
The birds fly to the same places and return to their original breeding grounds with amazing accuracy. During migration, it is usually the young birds that fly at the front and the older ones in the rear. Though the young ones have never flown that way, yet they fly to the right places and return to the right places covering hundreds of kilometers. They do not need any training in finding their direction during migration, for they are guided by instinct. Birds from north and north western parts of India fly to South India and Sri Lanka.
It is now found that some of the white strokes that are seen in India come from Germany.
Birds such as ducks and geese fly at a speed of between sixty-five and ninety kilometers per hour. Some birds fly from six to eleven hours a day. Some birds can fly 885 kilometers non-stop in about eleven hours. A bird known as the Eastern Golden plover which comes to India from western Alaska and North eastern Siberia flies 3200 kilometers non-stop. The snipe flies 4800 kilometers over the sea from Japan to Australia. There is scientific evidence to prove all this. They fly at a height of 1000 meters and 4000 meters above the ground.
More and more people are taking an interest in bird behaviour and in course of time, the answers to a lot of questions about bird migration will be available.