Julie Roellieh, age 12, of Rosalia, Wash. her question:

How many species of birds are there?

The word species means a distinct kind of plant or animal. Hence, the number of bird species should tell us how many different birds there are in the world. However, 3.n the bird world this is not so* Letts trace the family tree of the American robin redbreast and see why.

All birds, Mr. Robin included, belong to the animal class Aves. In order to qualify, a bird must wear feathers. Instead of arms or front legs, he must have wings. He must walk on only two feet. He must have a beak, no teeth and he must hatch from an egg.

The big Aves class is subdivided into smaller orders, according to certain bird features. The herons, storks and ibises are long necked, long legged wading birds who belong in the order Ciconiidae   the stork¬like ones.. Chickens, pheasants and turkeys, all plump birds who scratch for a lining, belong in the order Galliformes   meaning the chicken like ones. The lordly peacock is also a galliform.

More than half of all the birds, however, belong in the order Passeriformes   the sparrow=like ones. This is the great order of perching birds, so big that it is divided into suborders. One of the suborders is Oscines   the true songbirds. It includes the sweet singing robin, the throaty mockingbird, the warbling thrush and the happy lark.

Each order or suborder is divided into families. The velvety waxwing belongs in the family Bombycillidae   the little silky ones. The pert robin belongs in the family Turdidae   the thrushlike ones. Yes, he is first cousin to the speckled thrush.  

The family or subfamily is further divided in the genera, plural of genus. Mr. Robin’s family name is Turdus. Like the name of his order Turdidaes it is also taken from the Latin word for thrush. The genus~ includes the robin, the ouzel and their thrushy cousins.

Now we come to the species, or individual members, of the genus. The scientific name for a bird includes the name of his genus and the name of his species. Mr: Robin's fancy name is Turdus migratorius. He puts his family name first and spells his species name with a small letter. This must be the end of his family tree, for surely there is only one kind of robin.

Not at all. The robin of eastern America has a breast of solid rusty red. The western robin has a dark neckiace on h1s red weskit. Many birds have slight variations of this sort, depending upon where they live. We call them variations or subspecies. There are some 8,600 species in the class Aves. But if we count all the subspecies, there are 30,000 different members of the bird world.