There are between 325 and 340 species of hummingbirds in the world, all in the Americas. There is almost no fossil record, which is no surprise at all, given the small size and delicate nature of their bones. Just two specimens older than Pleistocene are known, in 30 million year old rocks from Germany, which is a bit of a surprise, given their present distribution. The ancient species are modern in their appearance.
To say that the birds are highly specialized is an understatement: their energy budget must be near the limits for terrestrial animals of any sort, their flight abilities are unique to say the least (the only bird that can fly backwards), and they have unique adaptations in their overnight activities that keep them from starving overnight (basically they hibernate). I found various notes on the "Google" that suggest these birds are "proof" of intelligent design, as they are too miraculous to ever have evolved. Oh...whatever. Some sources mention that the average hummingbird is always just hours from starvation. A bird that has to consume more than its own weight in nectar every day seems to suffer from an inefficient design parameter. I dunno...I just wanted to post a pretty picture for you all!
Photo of the day by Mrs. Geotripper.