Preening is an important part of a hummingbird's day.
A tiny Ruby-throated Hummingbird has about 940 feathers to keep in order, so it stops flying several times a day to preen. Preening helps keep the feathers clean and aligned properly, making hummingbirds more aerodynamic and their wings more efficient.
"I can tell the difference between the three birds that visit the feeder so I have named them: Spots (has spots on chest), Slick (think juvenile) and Itchy (who preens and fluffs all the time and really keeps a lookout for the other two."
Lin in Aurora, Illinois (August 28, 2013)