What exactly is a beak or bill? There is a core of bone of the upper and lower jaws, called mandibles. A horny layer of a material covers the bones. Both mandibles move in most birds, whereas in mammals only one jaw moves. Try opening and closing your mouth and see which jaw moves. Most birds move both.

Birds that eat seed, such as Northern Cardinals, have short strong bills that can crack open a hard-shelled seed easily.

Birds that eat flying insects have flat bills with a wide base so that they can catch a moving and small target, such as a gnat or fly.

Think of swallows and flycatchers.

Some birds flit through the leaves on trees, searching and devouring insects. These birds need long bills so that they can easily reach out and grab that bug crawling on a leaf. These bills are not as strong as the seed-eating birds since the insects are normally soft. Warblers and orioles are examples of these birds.

Raptors, such as eagles and hawks, have hooked bills that are sharp, making it easy to rip apart their prey.

Solitary still fishermen, such as egrets and herons, have very long sharply pointed bills that they use to spear the fish.

If you are on the coast, look at the many species that feed together on a mudflat or sandbar. Each species is searching for a different type of food, and each species usually will have a different shape and length of bill. Ruddy Turnstones, with short bills, will rummage about on the surface of the mud, while Whimbrels will forage the deepest in the muck with their very long bill.

Hummingbirds reach deep into the depths of trumpet-shaped flowers to lap up the nectar with their long thin bills. Although some people think their bills are essentially straws, hummer bills actually open and close just like other birds�? with long tongues lapping up the nectar.

Pelicans use their pouches on the lower mandible as fishing nets. These unique folds of skin, called gular pouches, widen as they dive underwater. Once the fish are caught, pelican drain the water from their pouches, tilt their head back and gobble down their fish dinners.

Crossbills are other birds with unique bills. Look closely and you will see that the tips of their bills cross over each other. These birds will pry open the overlapping woody petals of pinecones to eat the hidden seeds lying within.

Bills of puffins allow them to hold onto many slippery fish at one time, sometimes lined neatly up along their bill.

Black Skimmers are one bird that have lower bills that are attached firmly to their skull. They will fly over the water, dragging their lower bill in the water. When the bill touches a fish, it will snap quickly shut. The firmly fixed and attached lower mandible keeps the lower bill from being jerked off when dinner is caught.

Ducks and flamingos have still another type of bill, using them to filter the water for food. Although both are filter-feeding birds, think of the differences in the shape and style of feeding, with the strange, almost upside-down feeding of the flamingos.