PLAN OF THE WORK. 



Nomenclature.— The nomenclature of the American Ornithologists 

 Union's * Check-List of North American Birds has been adopted. The 

 number preceding the name of each species is its permanent number 

 in the Union's " Cheolc-List." 



Definition of Terms.— The accompanying figure with its named 

 parts will explain the meaning of the terms used in the following de- 

 scriptions of birds. The words, upper parts and under parts, men- 

 tioned so frequently, refer respectively to the whole upper or under 

 surfaces of the body of the bird from the base of the bill to the root of 

 the tail, but are not applied to either wings or fail. 



There are infinite variations in the markings of feathers, and those 

 figured present only the patterns most frequently met with. The 

 shaft of the feather is the midrib, to either side of which the vanes 

 or webs are attached. 



The Keys.— It is of the utmost importance to thoroughly under- 

 stand the use of the keys. At first sight they will, no doubt, appear 

 confusing, but in reality they are exceedingly simple. The system 

 upon which they are arranged may be mastered in a few minutes, and 

 you will then be surprised at the ease and rapidity with which, even 

 in large families, you can "run a bird down." 



The Key to Families. — Strictly speaking this is not one key but a 

 series of keys, one under each order. 



The orders are placed in a natural sequence — that is, we begin with 

 the oldest or lowest forms of birds. Loons, Grebes, etc., and end with 



* The American Ornithologists' Union is the leading society of its kind in 

 this country. Its membership includes the foremost ornithologists of the world, 

 and is divided into four classes : 1. Honorary members, limited to 25 in number. 

 2. Active members, limited to 50 in number, who must be residents of North 

 America. 3. Corresponding members, limited to 100 in number ; and 4. Asso- 

 ciate members, who must be residents of North America, and are not limited as 

 to number. The total membership of the Union in December, 1894, was 616. 

 Annual meetings are held, usually in Washington, New York, or Cambridge. 

 The Auk, the official organ of the Union, is a quarterly journal under the editor- 

 ship of Dr. J. A. Allen, at the American Museum of Natural History. 



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