Hummingbirds (family Trochilidae) are exclusively a New World or Western Hemisphere family. Most of the more than 300 species of hummers live in Central and South America. About 26 species visit the U.S. during part of the year and 17 breed here. They have long, slender bills and tube-like tongues. Hummingbirds make a living by drinking massive amounts of nectar (up to two times their body weight per day) and by eating insects they catch on the fly. The smallest is the bee hummingbird from Cuba weighing about .07 oz. The largest is the giant hummingbird weighing about .7oz. The calliope hummingbird is the smallest in the U.S. weighing about .1oz. Hummingbirds can hover motionless in the air, but are able to fly forward, backward, straight up, or straight down. They are called hummingbirds because the wing architecture and the rapid beat of their wings cause an audible hum when they fly.
Rocky Mountain National Park has reliable reports of six species of hummingbirds occurring within the park's boundaries. Broad-tailed hummingbirds (Selasphorus platycercus) are abundant throughout the summer. Rufous hummingbirds (Selasphorus rufus) are the next most common, and arrive about the first of July. Black-chinned (Archilochus alexandri) and calliope hummingbirds (Stellula calliope) are rare and magnificent (Eugenes fulgens),and ruby-throated (Archilochus colubris) hummingbirds are probably accidental visitors.
Until recently scientists thought that hummingbirds had evolved in the Western Hemisphere, although few fossils had been found of their tiny, fragile bones. An article in the journal Science* changed that notion. A researcher reported a 30 million year old fossil of an essentially modern hummingbird from southern Germany. The finding astounded bird taxonomists, but it does help to explain why some ancient species of flowers found in Europe appear to have evolved to accommodate a hovering hummingbird pollinator. If Europe is truly the original home of hummingbirds, they must have moved to the New World, then gone extinct in Europe.
Clearly, more research remains to be done on these fascinating "flying jewels."
*G. Mayer, Science, 304, 861 (2004).