August and September provide some of the year's best opportunities for observing hummingbirds in Illinois, according to Rob Kanter, author of The University of Illinois' Environmental Almanac. That's because individuals that have been farther north during the breeding season gather here on their way south.
Despite their small size, many hummingbirds migrate over long distances. Ruby-throats heading south may travel 2000 miles to reach their winter territory in southern Mexico and Central America, including a 500-mile nonstop leg of the trip over the Gulf of Mexico.
While the ruby-throated is the most common, rarer hummingbirds -- such as the broad-billed, Rufous and Allen's -- are seen across the Midwest from late summer into fall. The Rufous hummingbird is occasionally seen at feeders.