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Birds are a class of animals (''aves'') that can be distinguished from all other living animals by the presence of [[feather]]s.  They are two-legged, warm-blooded [[vertebrate]]s with [[wing]]s and they range greatly in size, the tiniest can fit on the palm of a human hand and the largest can be ridden upon.  The largest living bird species (the [[Ostrich]]es) are flightless.  Flight does not distinguish birds, because many insects have wings and can fly.
'''Bird'''s are a class of animals (''aves'') that can be distinguished from all other living animals by the presence of [[feather]]s.  They are two-legged, warm-blooded [[vertebrate]]s with [[wing]]s and they range greatly in size, the tiniest can fit on the palm of a human hand and the largest can be ridden upon.  The largest living bird species (the [[Ostrich]]es) are flightless.   
 
Most bird species exhibit [[sexual dimorphism]] to some degree, that is, that male and female birds look different.  It is usually the males which are the more brightly coloured.
Most bird species exhibit [[sexual dimorphism]] to some degree, that is, that male and female birds look different.  It is usually the males which are the more brightly coloured.


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Birds are extremely valuable to humans in several respects.  Domestic birds are raised for eggs and meat, called [[poultry]], and many wild bird species are hunted for food.  Other species are kept as [[pet]]s.  In addition, many birds eat insects that humans find irritating or destructive, and they consume [[weed]] [[seed]]s.  Finally, birds act as useful [[scavenger]]s around areas of human habitat.
Birds are extremely valuable to humans in several respects.  Domestic birds are raised for eggs and meat, called [[poultry]], and many wild bird species are hunted for food.  Other species are kept as [[pet]]s.  In addition, many birds eat insects that humans find irritating or destructive, and they consume [[weed]] [[seed]]s.  Finally, birds act as useful [[scavenger]]s around areas of human habitat.


There are more than 9,000 different bird species.  In terms of evolution, they are the most successful of the vertebrates; this is largely attributed to their ability to fly, which allows them to roam great areas and search out and adapt to a wide range of habitats.
There are more than 9,000 different bird species.


==Types of bird==
==Types of bird==

Latest revision as of 03:34, 17 October 2010

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Birds are a class of animals (aves) that can be distinguished from all other living animals by the presence of feathers. They are two-legged, warm-blooded vertebrates with wings and they range greatly in size, the tiniest can fit on the palm of a human hand and the largest can be ridden upon. The largest living bird species (the Ostriches) are flightless. Most bird species exhibit sexual dimorphism to some degree, that is, that male and female birds look different. It is usually the males which are the more brightly coloured.

Birds reproduce by laying eggs, as do reptiles and amphibians. The eggs are usually placed in nests, some of very intricate construction, some very casually put together, and incubated for a period.

Birds are extremely valuable to humans in several respects. Domestic birds are raised for eggs and meat, called poultry, and many wild bird species are hunted for food. Other species are kept as pets. In addition, many birds eat insects that humans find irritating or destructive, and they consume weed seeds. Finally, birds act as useful scavengers around areas of human habitat.

There are more than 9,000 different bird species.

Types of bird

Birds of Prey (raptors)

These include eagles and owls.

Waterfowl

Ducks, geese and swans are examples of waterfowl.

Flightless birds

Include ostriches, emus, penguins and puffins.