Hummingbird bills and tongues have evolved into perfectly designed tools for a diet of nectar and insects. The bill and tongue can reach deep into blossoms and draw up a flower's sweet nectar. Early researchers thought the tongue worked like a soda straw that sucked up nectar. But researchers Dr. Alejandro Rico-Guevara, Tai-Hsi Fan and Margaret A. Rubega at the University of Connecticut later used high-speed video to discover something different. The tongue, which is about twice as long as the hummer's beak, is forked into two narrow tubes. When the hummingbird feeds at a blossom, the tongue stays compressed in the beak as it shoots out. The tongue then springs open when it reaches the nectar within the flower. When immersed in fluids, the tip of the tongue splits and the flaps for each narrow tube unfurl. As the bird pulls its tongue in, the flaps snap shut to trap, seal and deliver the nectar to the bird's mouth. It's all automatic, taking less than 1/20th of a second—and is repeated thousands of times a day! A hummer's tongue can dart in and out of a flower 15 times a second, or faster!
Scientists were long puzzled because the beaks seemed to be shaped for extracting nectar from flowers, but not for hunting insects. Insects are important sources of protein for hummingbirds. Thanks again to high-speed photography, researchers discovered how a hummer bill snags insects. The lower half of the open beak will bend downward, even though it has no joint. This bending action pulls the hummer's mouth (gape) open wide enough to catch insects. When catching insects on the wing, hummers and other birds are said to be hawking.
Russ Thompson
