Hummingbirds are very interesting and unique birds for more reasons than might be readily apparent. In addition to possessing the ability to hover, they also have some unique anatomical features; have co-evolved alongside the flowering plants from which they derive energy, and have developed methods to conserve that energy; and are one of the only groups of birds that have a truly promiscuous mating strategy.

I found this picture on Facebook last semester immediately after taking an ornithology exam that covered the concept shown, and decided to share some of what I learned here, too. The information might be a bit more esoteric than what I normally write about, but I tried to make it as accessible as possible by including informative links.

Image via The Scientist

This image depicts the cursorial hypothesis of avian evolution, which states that birds are descendants of theropod (bipedal) dinosaurs, and that flight developed from the "ground up" through leaping after and/or "netting" insects. The alternative hypothesis is known as the pseudosuchian thecodont hypothesis, which contends that modern birds are directly descended from arboreal (tree-dwelling) archosaurs, and that flight developed from the "trees down" — first by parachuting, and then gliding between trees.