Mike Schneider, age 12, of Louisville, Ky., for his question:
How come the ostrich is a non flying bird?
There are several reasons why the world's biggest bird is permanently grounded. His breastbone is the wrong shape. He has feathery plumes instead of the stiff pinions that flying birds need to beat the air. But the major reason is overweight. There is a limit to the weight of flying birds and the huge ostrich is much too heavy to qualify for a pilot's license.
The largest flying birds have wide wings that span 6 feet or more. But their total body weight does not exceed 40 pounds or so. This seems to be the limit that nature sets for flight in the bird world. The average adult ostrich stands 8 feet tall and tips the scales at around 300 pounds. So far as we know, no bird of this size and weight ever was able to lift his bulk above the ground.
A flying bird has a tapered, keel shaped breastbone to support his mighty flying muscles. The ostrich has a flattish, raft shaped breastbone, and his mightiest muscles are in his legs. He is called a ratite bird, a name coined from an old word for a raft. gnus, rheas and cassawaries also are non flying ratite birds.
Nobody knows for sure whether the remote ancestors of the ostrich were flying birds. In any case, the big birds have been grounded for ages. Other birds use their flying skills to forage for food and to escape their enemies.
The ostrich has other means to cope with these problems. He is a fierce fighter. His long, strong legs carry him far and fast. His keen eyes spot trouble from afar, and he has a pocketful of clever tricks to defend himself and his family.
His large, farseeing eyes are fringed with thick lashes, though his head, his long neck and most of his mighty legs are almost featherless. His large wings and bully body are clothed with soft splendid plumage. The male wears black with huge white plumes on his wings and tail. The female's plumage is brown, delicately edged with creamy tan.
Those huge fluffy ostrich plumes look magnificent during courtship displays. They also are fine for shading the eggs from the seething African sunshine. But even if the ostrich weighed only 40 pounds, such feathers would keep him on the ground. A flying bird lifts himself aloft on cushions of air. To scoop up these lifting cushions, he needs the stiff pinion feathers of his wings and tail.
Hence, flight for the ostrich is quite out of the question. He is adjusted to life on the sunny plains of East Africa, where large herds of his kinfolk roam through most of the year. There they outsmart, outrun and sometime outfight lions and other mighty predators.
Such a fabulous bird was bound to start fabulous rumors, true or false. For example, though his main diet is vegetation, it is true that he may swallow a nail or two to aid his digestion. But the rumor that he buries his head to hide from his enemies is totally false. He is much too smart for such nonsense. Besides, he can run from his foes at 40 m.p.h., and when cornered he kicks like a mule armed with deadly daggers.