2 
BIRD-LIFE. 
CHAPTER IL. 
THE BIRD: ITS PLACE IN NATURE AND 
RELATION TO MAN. 
The Bird’s Place in Nature.*—About thirteen 
thousand species of birds are known to science. The 
structure of many of these has been carefully studied, . 
and all have been classified, at least provisionally. 
Taken as a whole, the class Aves, in which all birds are 
placed, is more clearly defined than any other group of 
. the higher animals. That is, the most unlike birds are 
more closely allied than are the extremes among mam- 
mals, fishes, or reptiles, and all living birds possess the 
distinctive characters of their class. 
When compared with other animals, birds are found 
to occupy second place in the scale of life. They stand 
between mammals and reptiles, and are more closely re- 
lated to the latter than to the former. In fact, certain 
extinct birds so clearly connect living birds with rep- 
tiles, that these two classes are sometimes placed in one 
group—the Sauropsida. 
* On the structure of birds read Coues’s Key to North American 
Birds, Part I] (Estes & Lauriat); Headley, The Structure and Life of 
Birds; Newton’s Dictionary of Birds—articles, Anatomy of Birds and 
Fossil Birds; Martin and Moale’s Handbook of Vertebrate Dissection, 
Part II, How to Dissect a Bird; Shufeldt’s Myology of the Raven 
(Macmillan Co.). 
1 
