Why Do Birds Have Different Bills?
The shape of a bird’s bill or beak is closely related to the kind of food it eats and the way in which it collects or catches this food. The bill shows various adaptations for methods of feeding. Birds with all-purpose bills have general sort of diet using a bill that can cut, crush, rip, and open just about anything.
A crow or jay has a strong all-purpose bill, capable of killing small mammals but fine enough at the tip to pick up small insects. Many songbirds have slender bills for picking up insects from leaves or out of cracks; others have wide flat ones for catching flies or strong thick ones for cracking seeds and nuts.
Birds which dig for worms usually have long bills with sensitive tips while many water birds have broad dredging bills. Divers and grebes have straight spear-like bills and the birds of prey have strong hooked bills for tearing flesh. Birds which catch insects on the wing (nightjars, swallows etc.) have tiny beaks but an enormous “gape” by comparison.
Some other examples are short thin bills for insect eaters, short thick bills for seed eaters, long thin bills can be for probing flowers for nectar or probing soft mud for worms and shellfish.
The Toco Toucan (Ramphastos toco), the largest member of the toucan family, possesses the largest beak relative to body size of all birds. The toucans use this exaggerated feature to attract mates and pick fruit from the thin ends of branches that cannot support the bird’s weight. A recent study also found the bill can help the bird keep its temperature under control.
Flamingos are filter feeders, and have many complex rows of horny plates that line their bills to strain food items from the water. Of course, gathering food is not the only use for the bird’s bills. Birds use their bills in fighting and in defense of their territory, gathering nesting materials, building nests, grooming feathers, attracting mates, scaring predators, and other important rolls.
The bird’s bill is a remarkably useful instrument that comes in all shapes and sizes. Although beaks vary significantly in size, shape, color and texture, they share a similar underlying structure. Two bony projections—the upper and lower mandibles—are covered with a thin keratinized layer of epidermis known as the rhamphotheca. In most species, two holes known as nares lead to the respiratory system.