List of birds of Costa Rica
Although Costa Rica is a small country, it is in the bird-rich neotropical region and has a huge number of species for its area. The Official List of the Birds of Costa Rica by the Costa Rican Rare Birds and Records Committee of the Asociación Ornitológica de Costa Rica (AOCR) contains 918 species. These 918 species are more than have been recorded in all of the United States and Canada combined. Of those species, six are endemic (three of which are found only on Cocos Island), 62 are rare or accidental, and four have been introduced by humans. Many are near-endemic with ranges that include only Costa Rica and northwestern Panama. Twenty-six species are globally threatened. Over an area of 51,100 km2, an area smaller than West Virginia, this is the greatest density of bird species of any continental American country. About 600 species are resident, with most of the other regular visitors being winter migrants from North America.
Costa Rica's geological formation played a large role in the diversification of avian species. North America and South America were initially separate continents, but millions of years of earthquakes and volcanic eruptions eventually fused the two continents together. When this happened, species from the north and south poured into the land bridge that became Central America. Birds like the hummingbird came from the south, while birds like the jay came from the north.
Part of the diversity stems from the wide array of habitats, which include mangrove swamps along the Pacific coast, the wet Caribbean coastal plain in the northeast, dry northern Pacific lowlands, and multiple mountain chains that form the spine of the country and rise as high as 3,500 m. These mountain chains, the largest of which is the Cordillera de Talamanca, form a geographical barrier that has enabled closely related but different species to develop on either side of the chain. A good example of this speciation is the white-collared manakin of the Caribbean side, which is now distinct from the orange-collared manakin of the Pacific slope.
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