Birds arose from reptiles some 225 million years ago, developing feathers and lightweight skeletons. In some, the necessary adaptions for sustained flight evolved, including a cardiorespiratory system composed of a powerfull four chambered heart and efficient counter-current gas exchange across the lungs. There are some 1700 bird species in North America, but if you exclude Central America, that number drops to about 645. This page covers those species found in or around the Great Lakes.
View photos and find information on Canada's aquatic birds.
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