North America, with about 900 species of birds, is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.
North America covers an area of about 24,709,000 square kilometers (9,540,000 square miles), about 16.5% of the earth’s land area and about 4.8% of its total surface.
In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7.5% of the world’s population, if nearby islands (most notably the Caribbean) are included.
Bird diversity varies dramatically throughout the world, with nearly 10,000 species of birds in virtually every terrestrial and aquatic habitat on earth. North America has about 900 species of birds and Mexico 1026; of course there is considerable overlap.