Found these nifty three inch long beasties hovering over the mountain phlox while sipping nectar in a hummingbird like manner, but they are not birds. They are a buncha lying MOTHS. Okay, maybe not considering that they are possessed of minuscule brains and so have little ability to intend anything, but they do look like hummingbirds and are almost the same size.
These particular guys are clearwing hummingbird moths, Hemaris thysbe. The hummingbird part of the name is as mentioned above. The clearwing part is due to large “windows” on each wing that do not possess the normal scales of a moth or butterfly, so you can see right through them. Cool, eh?
“Hemaris thysbe.” Encyclopedia of Life, available from http://www.eol.org/pages/50710/overview. Accessed August 13, 2015.