Hummingbirds can flap their wings up to 50 times per second as they hover over flowers to extract nectar. It has long been thought by biologists that this was done by 'wicking,' or capillary action that allows liquid to flow through small spaces without benefit of gravity. A UConn study recently published in an issue of Proceedings of the Royal Society B: Biological Sciences, disproves that theory.
The research came to the conclusion that the hummingbird's tongue was actually working as a tiny pump.
One of the researchers, Rico-Guevara, explains that rather than wicking, the nectar is drawn into the tongue by the elastic expansion of the grooves after they are squeezed flat by the beak. To make more sense of this, check out this slow motion video of the hummingbird in action.