By Susan Benson,
CNHM Director of Education
Just think about a crossbill, spoonbill, bluebill, ivory-billed woodpecker, great hornbill, channel-billed toucan, yellow-billed stork, saddle-billed stork, or shoebill stork – all birds that are named because of their bills. Others are named for their mandibles, which is what the top and bottom parts of a bird’s bill are called, such as the black or chestnut-mandibled toucan. Then ponder the use of your own mouth, and compare it to that of birds, which use their bill for eating, killing prey, probing for food, grooming, manipulating objects, courtship, and feeding their young. Bird bills show amazing diversity, both in physical anatomy and their use. Check out the following bill facts:
• Bill anatomy – the jaws of a bird’s bills are made of a hollow or porous bone designed light for flight. The outside of the bill is covered with keratin, the same material in our fingernails. Bird bills have two holes called nares that connect to their respiratory system. When birds open their mouths, the lower jaw does most of the movement. Their bills continue to grow throughout their lives in order to replace the wearing that occurs at the tips.
• What are some of the common bill types? First, there is the probe, such as hummingbirds, that have long straw-like bills to sip nectar from flowers. Next are the chisel-like beaks, such as woodpeckers, that chisel for food or cavities. Some birds, such as herons or mergansers have spears, bills with serrated edges and a hooked point for grabbing fish. Birds of prey have hooked bills for tearing apart their live prey into pieces small enough to swallow. Blackbirds, meadowlarks, and warblers have tweezer-like bills for probing for insects. Flycatchers and goatsuckers have wide bills surrounded by a net of bristles that funnel flying insects into their mouth while in flight. Nutcrackers such as grosbeaks, sparrows, and finches have thick, conical beaks, for cracking open the hard outer shells of seeds. A kitchen strainer is similar to the edges of a duck's bill which is fringed to strain plants, seeds, and small invertebrates from mud and water. Finally are the burrowing birds, such as stilts, woodcocks, or avocets, which have thin, probing bills to jab in the mud.
• It is worth peeking at the local American woodcock bill, which has a flexible tip specially adapted for probing into moist soil in search of earthworms. It is believed that this bird steps heavily, causing worms to move more in the soil. Their beak then probes and feels the worms in the moist soil.
• Crossbills also have an odd, crossed bill that assists them with getting into tightly closed cones. Their jaw muscles are strong, so the bird places its bill tip slightly open under a cone seed, and then bites down. The crossed tips then push the cone scale up, exposing the seed underneath.
• Looking around the world, there are interesting bird bills as well. The sword-billed hummingbird has a bill is longer than its body. A skimmer’s lower mandible is larger than the top mandible, allowing them to place this part of their bill into the water, flip fish into the air, and catch them. The shoebill has a bill that looks like a shoe, and these birds use their bill in muddy waters, preying on fish, frogs, young crocodiles, invertebrates and small mammals.
The United State Fish and Wildlife Service reports that birdwatching brings in $36 billion annually to our economy, and its no secret why. Having a bird life list is not enough for many of us. Imagine being able to watch a skimmer skim for fish, or to observe with binoculars a crossbill pull seeds out of a cone. These kinds of experiences are priceless.
For over 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, Our Shared Planet, in Cable at 13470 County Highway M. Also find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Post your own stories on the Nature Watch blog at cablemuseumnaturewatch.blogspot.com.