In the present volume, therefore, an attempt has been made so to group, figure, and describe our birds that any species may be named which has been _definitely seen_. The birds are kept in their systematic Orders, a natural arrangement, readily comprehended, but, further than this, accepted classifications have been abandoned and the birds have been grouped according to color and markings.
A key to the Orders gives the more prominent characters on which they are based; telling for example, the external differences between a Duck and a Grebe. In comparatively few instances, however, will the beginner have much difficulty in deciding to what Order a bird belongs. Probably eight times, out of ten the unknown bird will belong to the Order Passeres, or Perching Birds, when one has only to select the color section in which it should be placed, choose from among the colored figures the bird whose identity is sought, and verify one's selection by reading the description of the bird's characteristics and the outline of its range.
In the case of closely related species, and particularly subspecies, the subjects of range and season are of the utmost importance. Most subspecies resemble their nearest allies too closely to be identified in life by color alone, and in such cases a bird's name is to be learned by its color in connection with its distribution and the season in which it is seen.
During the breeding period, unless one chance to be in a region where two races intergrade, subspecific names may be applied to the bird in nature with some certainty, for it is a law that only one subspecies of a species can nest in the same area; but during migrations and in the winter, when several subspecies of one species may be found associated, it is frequently impossible to name them with accuracy.
For example, during the summer one need have no hesitancy in calling the Robins of the lowlands of South Carolina the Southern Robin (_Planesticus migratorius achrusterus_) but later, when the Northern Robins (_Planesticus migratorius migratorius_) begin to appear, it would be difficult, if not impossible, to distinguish them in life from the resident birds.
If it were possible to impress the student, who proposes to name the bird in the bush, with the _absolute necessity_ for careful, definite observation he would be saved many disappointing and discouraging experiences.