6 HOW BIRDS ARE NAMED 
that every bird he sees has a name, and in the preceding section having 
suggested ways in which this name may be learned, the somewhat 
obscure details of nomenclature may be made clearer by explaining 
how the bird got it. In doing so I draw freely from a similar effort in 
the “Color Key to North American Birds.” 
Birds have two kinds of names. One is a common, vernacular or 
popular name; the other is a technical or scientific name. The first 
is usually given to the living bird by the people of the country it in- 
habits. The second is applied to specimens of birds by ornithologists 
who classify them. Common names in their origin and use know no 
law. Technical names are bestowed under the system of binomial 
nomenclature established by Linneus in 1758, and their formation 
and adoption are governed by certain definite, generally accepted rules. 
The Linnaan system, as it is now employed by most ornithologists, 
provides that a bird, in addition to being grouped in a certain Order, 
Family, etc., shall have a generic, a specific, and, often, a subspecific 
name which, together, shall not be applied to any other animal. 
Generally speaking, Orders and Families are based on skeletal, 
muscular, and visceral, or what may be termed internal characters; 
while genera are based on the form of bill, wings, feet and tail, and 
sometimes on pattern of markings, and species and subspecies on color 
and size, or external characters. Thus, all the members of an Order 
agree in major internal characters; those of a Family further agree in 
minor internal characters; those of a Genus, in addition, resemble one 
another in external characters, while species and subspecies differ only 
in color and in size. 
Frequently it happens that a bird may possess some of the char- 
acters of one group in connection with some of the characters of another 
group, and such birds, collectively, create intergrading groups known 
as Suborders, Subfamilies, Subgenera, or Subspecies. With the last, 
the student is especially concerned since they figure in the name by 
which a bird is known. 
In pre-Darwinian days it was generally believed that a species was 
a distinct creation whose characters did not vary from a certain type. 
But in later years comparison of many specimens of a species from 
throughout the region it inhabits, shows that specimens from one part 
of a bird’s range may differ in size and color, or both, from those taken 
in another part of its range. At intervening localities, however, inter- 
mediate specimens will be found connecting the extremes. (See beyond, 
under Color and Climate.), 
Variations of this kind are termed geographic, racial or subspecific 
and the birds exhibiting them are known as subspecies. In naming 
them, a third name, or trinomial is employed, and the possession of 
such a name indicates, at once, that the bird is a geographic or racial 
representative of a species with one or more representatives of which 
it intergrades. 
In illustration let us now trace the history of a trinominal designa- 
