Birds hatch from eggs of all colors: blue, green, brown, white, speckled, and plain. Besides coming in various colors, the eggs differ greatly in size, shape, and number, according.
Among modern birds the hummingbird produces the smallest eggs, the ostrich the largest. In prehistoric times the elephant bird of Madagascar laid an egg fifteen inches long.
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| hungry baby sparrows |
From this great variety of eggs comes a comparable variety of birds. While the eggs are being incubated, or protected from cooling and overheating, the young bird is developing and using up the food within the egg. By the time it is ready to hatch, all the food is used up, and the baby bird fills the shell.
Newly hatched birds may be divided into two large groups, those wide-awake, covered with down, and quite able to take care of themselves, and those hatched naked and helpless, with eyes closed. Generally speaking, ground-nesting birds like the sandpiper and meadowlark belong to the first group; tree nesting birds like the robin and bluebird to the second.
After baby birds have been hatched, they are brooded or covered by the old birds to protect them from cold and heat.
Young birds grow very rapidly. It has been said that if a human baby grew at the rate that a bird baby does, it would weigh over a hundred pounds by the time it was ten days old.
All this growing means that young birds need an enormous amount of food‚ in fact, they eat almost continually from dawn to dusk.
Usually the hungriest baby opens his mouth the widest, sticks his neck out the farthest, and gets fed before the rest. Fortunately, nature has provided a control for him; when a greedy baby has had more than he needs, the muscles contract, and he can swallow no more. Then the parents can
concentrate on stuffing the rest of their hungry offspring.
A few figures will help you to picture the parent birds‚ problems:
- Young crows require at least one-half their weight in food merely to exist. They can consume their full weight in food in a day.
- One baby robin swallowed 14 feet of earthworms in one day. Another ate 68 worms‚ or about 17 feet.
- Baby hummingbirds are usually fed once every 20 minutes.
- A baby rose breasted grosbeak was fed 58 times between 4 and 5 p.m.
- A pair of grosbeaks fed their young 426 times in 11 hours.
- A pair of house wrens came to the nest with food 1217 times in 15 hours and 45 minutes of daylight, or more than once a minute.
Young birds can't fly until they lose their down and acquire real feathers. The first few experimental flights are fun to watch, for the short wings and undeveloped tail make the baby bird wobble uncertainly, as a human baby toddles unsteadily. The parent birds are usually nearby to encourage and protect their offspring until they are able to reach the security of the treetops. After that the babies are pretty much on their own.
As the young birds grow, their plumage gradually takes on the adult color and pattern, and their voices change‚ from the baby cries for food to the adult calls and songs. The amount of time necessary for these changes varies, of course, in different species.
After the young bird becomes an adult, it will find a mate, build a nest, and take on the responsibilities of raising a family‚ and once again we're back to the colored and speckled eggs. Whipple
Review vocabulary from freedictionary.com:
Craft paper birds to enhance the lesson:
Review vocabulary from freedictionary.com:
- contract - To be drawn together so as to be diminished in size or extent; to shrink; to be reduced in compass or in duration; as, iron contracts in cooling; a rope contracts when wet.
- ground-nesting
- incubated - of incubate - To sit, as on eggs for hatching; to brood; to brood upon, or keep warm, as eggs, for the purpose of hatching.
- prehistoric - Of or pertaining to a period before written history begins; as, the prehistoric ages; prehistoric man.
Craft paper birds to enhance the lesson:
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