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			          Bird - Wikipedia, the free encyclopedia
			           
			          Birds are a group of endothermic vertebrates, characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton.
			            https://en.wikipedia.org/wiki/Bird
			         
			       
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			          List of birds by common name - Wikipedia, the free encyclopedia
			           
			          In this list of birds by common name, a total of 9,721 bird species are recognised, belonging to a total 204 families.
			            https://en.wikipedia.org/wiki/List_of_birds_by_common_name
			         
			       
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			          Bird migration - Wikipedia, the free encyclopedia
			           
			          Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate.
			            https://en.wikipedia.org/wiki/Bird_migration
			         
			       
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			          Online Bird Guide - All About Birds
			           
			          The Cornell Lab of Ornithology is a world leader in the study, appreciation, and conservation of birds. Our hallmarks are scientific excellence and technological innovation to conserve and help birds
			            https://www.allaboutbirds.org
			         
			       
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			          Birds - ARKive
			           
			          Most popular birds. View videos and photos of 50 of the most popular birds in nature. Learn more about their biology, threats and conservation.
			            http://www.arkive.org/birds/
			         
			       
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			          Birds - Audubon
			           
			          Audubons mission is to conserve and restore natural ecosystems, focusing on birds, other wildlife, and their habitats for the benefit of humanity and the earth's biological diversity.
			            https://www.audubon.org/birds
			         
			       
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			          10 Facts About Birds
			           
			          Facts about birds, a group of vertebrates that includes nearly 10,000 species that are unique for their feathers and furculas, also know as wishbones.
			            http://animals.about.com/od/birds/a/bird-facts.htm
			         
			       
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			          Birds - National Zoo
			           
			          Here are the animals at the National Zoo listed in alphabetical order. Most can be seen at the Bird House.
			            http://nationalzoo.si.edu/Animals/AnimalIndex/birds.cfm
			         
			       
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			          Birds, Bird Pictures, Wild Birds - National Geographic
			           
			          Learn all you wanted to know about birds with pictures, videos, photos, facts, and news from National Geographic.
			            http://animals.nationalgeographic.com/animals/birds
			         
			       
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			          American Bird Conservancy
			           
			          ABC is the Western Hemisphere's bird conservation specialist  -  the only organization with a single and steadfast commitment to achieving conservation results for birds and their habitats throughout the Americas.
			            https://abcbirds.org
			         
			       
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			          Wild Birds Unlimited
			           
			          With more than 30 years of bird feeding experience and expertise, Wild Birds Unlimited specializes in bringing people and nature together with quality bird food, bird feeders, bird baths and other nature products.
			            http://www.wbu.com
			         
			       
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			          Bird Search By Name
			           
			          Use our Bird Guide to identify birds, learn about the life history, listen to the sounds, and watch bird behavior on video from the most comprehensive guide to North American birds
			            https://www.allaboutbirds.org/guide/search
			         
			       
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			          The Basics of Bird Migration: How, Why, and Where
			           
			          Of the more than 650 species of North American breeding birds, more than half are migratory. Find out why they migrate, types of migration and more.
			            https://www.allaboutbirds.org/the-basics-how-why-and-where-of-bird-migration