Science
What makes an animal a bird?
Quick answer
Birds are warm-blooded animals with feathers, wings and a beak. They lay hard-shelled eggs, and most can fly. Penguins, ostriches and parrots are all birds.
In one sentence
A bird is a warm-blooded animal with feathers, two wings and a beak that lays eggs.
Explained
Many animals fly, but only birds have feathers. Feathers keep birds warm and dry, and the long ones on the wings and tail help them fly. Birds also have:
- Two wings and two legs.
- A beak (also called a bill), with no teeth. Beak shape matches the food: a hawk has a hooked beak for tearing meat, a woodpecker has a sharp one for drilling, and a pelican has a pouch for fish.
- Warm blood: they keep a steady body temperature.
- Light bones: many bones are hollow, which helps flying birds stay light.
- Eggs with hard shells. Birds lay eggs, often in a nest, and keep them warm until the chicks hatch.
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parrot
owl
Not all birds fly. Ostriches, emus, kiwis and penguins have wings that work differently. Ostriches are the biggest birds, up to 2.7 metres tall, and can run at about 70 kilometres per hour. The bee hummingbird, from Cuba, is the smallest, at about 6 centimetres long. Penguins use their wings like flippers to swim.
There are about 10,000 species of bird. Some, like swallows and Arctic terns, make long migrations each year, flying thousands of kilometres. Others stay in one place. Birds sing, call and dance to attract mates and defend their territory.
Scientists agree that birds are living descendants of some kinds of dinosaurs; see dinosaurs. Birds belong to the group of animals with backbones, described in vertebrates and invertebrates. The path from egg to adult is a life cycle.
Examples
| Bird | Special feature |
|---|---|
| Ostrich | the largest bird, cannot fly |
| Penguin | swims instead of flying |
| Owl | hunts at night, silent flight |
| Parrot | strong curved beak, can copy sounds |
| Hummingbird | tiny, hovers in the air |
Common mistakes
- "All birds can fly." Penguins, ostriches and kiwis cannot.
- "Bats are birds." Bats are mammals with fur.
- "Birds are the only animals with wings." Insects and bats have wings, but only birds have feathers.
Quick quiz
Birds
Check what you know with 4 quick questions.
Question 1 of 4
Which feature do all birds have?
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Related topics
Living things
Living things are organisms that grow, feed, get rid of waste, sense the world and reproduce. Plants, animals, fungi and bacteria are all alive.
Life cycles
A life cycle is the series of changes a living thing goes through from the start of its life to becoming an adult that can produce young, so the cycle begins again.
Vertebrates and invertebrates
Vertebrates are animals with a backbone, like fish, amphibians, reptiles, birds and mammals. Invertebrates have no backbone, like insects, spiders, snails, worms and jellyfish.
Adaptation
An adaptation is a feature or behaviour that helps a living thing survive where it lives. A polar bear's thick fur and a cactus's spines are adaptations.
Amphibians
Amphibians are cold-blooded animals with thin, moist skin that live part of their lives in water and part on land. Frogs, toads, newts and salamanders are amphibians.
Blood
Blood is the red liquid pumped around your body by your heart. It carries oxygen and food to every cell, takes away waste and helps fight germs and heal wounds.