The Birds of New Jersey. 



Birds constitute a distinct class of vertebrate or back-boned animals, 

 but are more closely related to the reptiles than they are to the mam- 

 mals. 



They are distinguished from all other animals by their covering of 

 feathers. Birds, furthermore, are especially adapted for flight, the 

 forelimbs being modified into wings, which are composed mainly of 

 the long, stiff "quill feathers" known as remiges, those attached to 

 the "hand" portion of the wing being the primaries and those attached 

 to the forearm being the secondaries, while the several innermost ones, 

 often differently colored from the others, are the tertials. 



The bird's foot is also curiously modified. The heel is elevated, and 

 is usually held up near the body, while the long section between it and 

 the toes, which is covered with horny plates or scales (rarely feathers), 

 is known as the tarsus, and corresponds to the "instep" of a man's 

 foot. The feet are webbed, elongated, etc., according to the various 

 methods of progression. The bird's jaws are encased in horny sheaths 

 forming the bill, which exhibits great diversity of shape and structure 

 according to the varying food habits of the different species. 



Birds are hatched from eggs which are laid in nests especially pre- 

 pared for their reception, and are incubated by the parents, the female 

 performing the greater part of this labor. 



Existing birds comprise two main groups the Ostriches and their 

 allies on the one hand, and all other birds on the other. 



The latter are variously subdivided, the groups represented in New 

 Jersey being distinguished in the following key, which is to be used 

 as the first step in identifying an unknown bird, the page references 

 taking one on to the various family keys contained in the main text. 



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