Some facts about birds
- Birds (class Aves) are alike in ways that are easy to see. They cannot all fly, but they all have 2 wings. They cannot all run about on the ground, but they all have 2 legs. They all, moreover, have beaks.
- Like mammals, birds are warm blooded. Their bodies are even warmer than ours. Some birds have normal temperatures of as high as 112 degrees Fahrenheit.
- In the whole world there are about 10,000 kinds of birds. There are about 800 in the United States.
- The earliest known bird is the Late Jurassic Archaeopteryx, around 150–145 Mya (million years ago).
- Most birds are streamlined, and they are light in weight for their size.
- Birds are light partly because many of their bones are hollow. Besides, they have tiny air sacs scattered throughout their bodies. The air sacs act like little balloons. The feathers of the birds' wings and tail are a big help in flying. Their strong wing muscles are, too.
- Birds inhabit ecosystems across the world, from the Arctic to the Antarctic.
- Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) Ostrich.
- An ostrich is hundreds of times as big as a scarlet tanager.
- An ostrich cannot fly.
- Most paleontologists regard birds as the only clase of dinosaurs to have survived the Cretaceous–Tertiary extinction event approximately 65.5 million years ago.
- A robín is much more like a bluebird than it is like a loon. In the same way, a hawk is much more like an eagle than it is like a woodpecker. Ways they are alike and ways they are different have been used to divide birds into groups. Among the many groups are the ducks, geese, and swans; the owls; and the parrots. Our songbirds are all in the very biggest bird group — the perching birds.
- All living species of birds have wings - the now extinct flightless Moa of New Zealand was the only exception.
- About 120–130 species of birds have become extinct as a result of human activity since the seveneenth century, and hundreds more before then.
