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Birds
Birds Guide
Birds | Aviculture | Bird migration flyways | Bird topography | Birds by classification | Birds by geography | Birds of prey | Birdwatching | Bird diseases | Extinct birds | Famous birds | Feathers | Fictional birds | Flightless birds | Heraldic birds | Oology | Poultry | Prehistoric birds | Seabird | Shorebirds | Swifts | Wading birds | License
Birds
Fossil range: Late
Jurassic - Recent |
Superb Fairy-wren, Malurus cyaneus,
juvenile
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Scientific classification |
| Kingdom: |
Animalia
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| Phylum: |
Chordata
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| Subphylum: |
Vertebrata
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| (unranked) |
Archosauria
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| Class: |
Aves
Linnaeus, 1758 |
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Birds are
bipedal, warm-blooded, oviparous vertebrate animals
characterized primarily by
feathers, forelimbs modified as
wings, and (in most) hollow bones.
Birds range in size from the tiny
hummingbirds to the huge
Ostrich and
Emu.
Depending on the
taxonomic viewpoint, there are about 8,800–10,200 living
bird species (and about 120–130 that have become
extinct in the span of human history) in the world,
making them the most diverse class of
terrestrial
vertebrates.
Birds feed on
nectar, plants, seeds, insects, fish, mammals, carrion, or other birds.
Most birds are
diurnal, or active during the day, but some birds, such
as the
owls
and
nightjars, are
nocturnal or crepuscular (active during twilight hours), and many
coastal
waders feed when the tides are appropriate, by day or
night.
Many birds
migrate long distances to utilise optimum habitats
(e.g., Arctic Tern) while others spend almost all their time
at sea (e.g. the Wandering Albatross). Some, such as Common
Swifts, stay aloft for days at a time, even
sleeping on the wing.
Common characteristics of birds include a bony
beak with no teeth, the laying of hard-shelled
eggs, high
metabolic rate, a 4-chambered heart, and a light but
strong
skeleton. Most birds are characterised by
flight, though the
ratites are flightless, and several other species,
particularly on islands, have also lost this ability.
Flightless birds include the
penguins,
ostrich,
kiwi, and the extinct
Dodo. Flightless species are vulnerable to extinction when
humans or the mammals they introduce arrive in their
habitat. The Great Auk, flightless
rails, and the
moa
of
New Zealand, for example, all became extinct due to
human influence.
Birds are among the most extensively studied of all
animal groups. Hundreds of academic journals and thousands
of scientists are devoted to bird research, while amateur
enthusiasts (called birdwatchers or, more commonly,
birders) probably number in the millions.
by Nicolae Sfetcu, for
Animal Kingdom USA
This guide is licensed under the
GNU Free Documentation License
Birds Guide, made by MultiMedia | Free content and software
This guide is licensed under the GNU
Free Documentation License
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