Fluid mechanics of Hummingbird Drinking
There's a cool article that my wife linked me to, about how Hummingbirds drink. Apparently the thought was that they drink via capillary action, but the models suggested that they should prefer lower sugar solutions than they actually do (high sugar increases the viscosity, so slows the capillary rise). Someone finally set up a high speed camera and saw how they actually drink. It's an interesting video.
The video is a little hard to interpret, so here's the description as I understand it:
The hummer inserts its tongue in the flower, at this point a sort of groove opens up and traps some liquid, then as the hummer extracts the tongue, the groove clamps closed, so that the trapped liquid is pulled back into its mouth. No-one really knows how they swallow.
