Hummingbirds are found only in the Americas. The majority of species occur in tropical Central and South America, but several species also breed in temperate areas. Only the Ruby-throated Hummingbird breeds in continental North America and can be found east of the Mississippi River and Great Lakes. The Black-chinned Hummingbird, a close relative of the Ruby-throated Hummingbird and another migrant, is the most widespread and common species in the western United States, while the Rufous Hummingbird is the most widespread species in western Canada.
Most hummingbirds of the U.S. and Canada migrate south in fall to spend the northern winter in Mexico or Central America. A few southern South American species also move to the tropics in the southern winter. A few species are year-round residents in the warmer coastal and interior desert regions. Among these is Anna’s Hummingbird, a common resident from southern California inland to southern Arizona and north to southwestern British Columbia.
The Rufous Hummingbird is one of several species that breed in western North America and are wintering in increasing numbers in the southeastern United States, rather than in tropical Mexico. This believed to be due in part to artificial feeders and winter-blooming gardens, and this may result in the birds having altered internal navigation instincts that could be passed on to their offspring.