A bird's real home is the place where it raises its family. Many birds have also a temporary home. In North America, as you know, there is great difference between winter and summer.
The butterflies and bees and grasshoppers and bugs that swarmed in the fields and woods during the summer, disappear when cold weather comes. The frost kills some of them, and the rest go to bed for the winter in the ground, or under a stone, or behind a piece of bark.
When insects are scarce and those that are left are well hidden, it is hard for birds to find food. About this time of year most of our birds fly south for the winter. They don't fly away because food is hard to find. Most of them go before their food supply becomes scarce.
There are several different kinds of migrants and when birds are not traveling, they are called residents.
There are three kinds of bird travelers:
The Evening Grosbeak is an irregular migrant.
It might almost be called a wanderer. It builds its nest in the Canada but no one ever knows how far south it will spend the winter.
Usually it flies as far as the Great Lakes, but it has been known to go down to Kentucky or to southern California. In some years it is common and in some years it is very rare.
During the summer following a long southern migration, it sometimes builds its nest south of its regular summer home.
It is easy to see why the Evening Grosbeak is called an irregular migrant. One can not be quite sure what it is going to do next
The Junco is a regular migrant.
It nests in the Canada like the Evening Grosbeak, but it has a schedule and it sticks to it.
Juncos come down from the north in October and return to their summer homes in April.
During the winter they stay together in flocks of ten to a hundred or more.
The Cardinal that everyone knows and loves is hardly a traveler at all. He is called a permanent resident because he spends the whole year near the place where he was hatched.
When cold weather comes, Cardinals flock together in sheltered places, but ordinarily they do not travel far. In late February or March while the snow is still on the ground, the Cardinal's cheery whistle can be heard.
It is very strange that birds that live in the northern part of the world are much more migratory than their cousins in the south.
Some of the birds in Africa and Australia and South America travel a little. But their journeys do not compare with those of the birds of North America and Europe.
Many thousands of years ago, all of Canada and much of the United States was covered with ice. The ice didn't melt in the summer for there was too much of it. That time was called the Ice Age.
Of course no birds could live on the ice. There was no food for them, no insects or weed seeds. They lived as close to the ice as they could, for they were probably very much crowded in the southern part of the country. At last the world began to get a little warmer and the southern edge of the ice began to melt.
The ice began to retreat until it reached the Arctic regions around the North Pole where it never melts.
While the ice was see-sawing back and forth, birds followed it closely, because they were so crowded in the south that they had to have room in order to raise their families and to keep themselves from starving. Finally it became a habit. Every year they did the same thing and their children followed their example. Those that didn't develop the habit, died and were crowded out because they couldn't compete with their stronger and better fitted relatives.
This is a theory because nobody lived at that time and we will never know exactly what happened. But it is the best theory of the beginnings of migration.
That is why birds that live in the northern hemisphere, north of the Equator, have the longest and strongest migrations. Only a few birds south of the Equator have long migrations because there was no great Ice Age in the southern hemisphere.
Not all American birds that travel, however, build their nests in the north. There is a small group of sea-birds that is the exception to the rule. These are the Petrels and even then, only a few Petrels have this curious reversed migration. They nest in the far south on islands in the oceans towards the South Pole. They spend their winters with us just as some of our birds spend their winters in Central and South America.
Spring and fall are the seasons when most birds are migrating, but in every month of the year some birds can be found traveling. From the first of March until the end of May thousands and thousands of birds move northwards towards their summer homes. The greatest rush is during the two middle weeks of May. More birds are on their travels then than at any other time.
Most small birds do not attempt to make the trip between North and South America all at one time. They travel a hundred miles or so and then stop and rest for a few days. They feed and get energy and strength for the next part of the journey.
Some birds, like Ducks and Geese, follow freezing weather north and south as it changes in early spring.
Not so the Robin and the Bluebird. Their beautiful songs always make us think that "Spring has come." Sometimes they are wrong. But they don't retreat. They are the first and the hardiest of spring migrants.
Some birds fly very fast, many at a rate of about sixty miles an hour. Of course, if they fly with the wind they will go faster.
The fastest of all birds are the Swifts. They have been given this name because they are able to travel so rapidly. Swifts are known to fly more than a hundred miles an hour.
A bird's fuel, of course, comes from the food that it eats. No matter whether a bird eats insects or seeds or fish or worms, some of its food is changed into fat.
A bird stores its fuel in deposits of fat just under the skin. When it goes on a long journey, it uses this up just the way an airplane uses up the gasoline in the tanks.
Among many kinds of birds, the old ones migrate first and the youngsters are left to follow on as best they can. During the middle of the flight, there are both old and young together. The last to migrate are all young. Here again they must depend on their sense of direction.
At the end of the summer there are two or three times as many birds in the north as there were in the spring. Every pair of birds has raised a family, some of them two families of youngsters. Hummingbirds and Nighthawks have had two babies, other small birds four or five. Wrens and Chickadees eight or ten, and some Ducks and Rails as many as fifteen. Nature is careful to see that this overproduction always takes place.
There must be a sufficient supply of youngsters growing up to offset the accidents that are bound to happen. Each kind of bird has its own special enemies as well as a special set of dangers that it may encounter.
You might think that a Chickadee would have less dangers to overcome than a Hummingbird, but this is not true. The Ruby-throated Hummingbird travels thousands of miles every year and the Black-capped Chickadee stays at home.
Yet the Hummer lays only two eggs and the Chickadee seven to nine. Each spring there are no more Chickadees and Hummers than there were the year before, so one can be sure that the Chickadee has a harder time escaping from his enemies than the Hummer.
One cannot think of the travels of birds without realizing what wonderful journeys they make.
If, in proportion to his size, a man traveled as far as a Rufous Hummingbird does between its summer and winter homes, he would be able to go half the distance from the earth to the sun, forty-five million miles in two months. If, again in proportion to his size, a man could travel as fast as a Hummingbird, he would be able to circle the earth, twenty-five thousand miles, in three minutes.
Perhaps this may give you an idea of what migration means to a Hummingbird!. See Hummingbird Migration Map
Mar 29, 17 10:05 PM
Was going to rescue what I was told was a white dove. Well, this guy was huge, probably bigger than a macaw. He had a bit of a hawk-like look but seemed
Mar 27, 17 02:02 PM
I can't identify this bird. It was tall, and was perching in a tree over a swamp near the Kennedy Space Center parking lot. Very pronounced ruff of brown
Mar 27, 17 02:00 PM
We have old birdhouses in yard that are occupied and we want to replace them. When is it the best time to do so and will the birds have time to replace