|The hummingbird (Archilochus colubris) drinking from a transparent feeder; Credit: © Wonjung Kim, Franc¸ois Peaudecerf, Maude W. Baldwin, and John W. M. Bush|
If you are drinking from a straw this weekend you may notice that some of the water or whatever you are drinking using a straw rises in the straw more than the water in the glass. This occurs because the surface tension of the water and its attraction to the straw are stronger than gravity. The same effect will also occur if you place a sponge in water so the water rises through the different bubbles of the sponge defying gravity. This movement through a thin tube and through bubbles is called capillary action.
So it is no surprise that plants use this for their root system and animals use it. Capillary action in hummingbird's tongues was recently found to do the same thing by researchers at MIT :
they use 'an incredible self-assembling capillary siphon. Because nectar is stored in shallow, small scale areas in flowers, the tongue is not under the surface but rather adopts capillary action as its preferred method of taking out the "juice."' (as EarthTimes reports)
This is likely how the small hummingbird has survived. It has exploited this small niche allowing itself to drink the nectar other birds cannot reach. Surface tension properties allows the hummingbird to be awesome!
See full article here.