THE BIRD STUDY BOOK 



knows that Bald Eagles are comparatively rare, and 

 that Robins and Chipping Sparrows exist by millions. 

 The Number of Birds in Different States. — The num- 

 ber of kinds of birds found in any one State depends 

 on the size of the State, its geographical situation, and 

 the varieties of its climate as affected by the topog- 

 raphy in reference to mountains, coastlines, etc. 

 The number of "bird students and the character of 

 their field studies determine the extent to which the 

 birds of a State have been catalogued and listed. 

 The following list indicates the number of kinds of 

 birds that have been recorded in forty-three of the 

 States and the District of Columbia. The authority 

 for the statement in each instance and the year in 

 which the figures were given is also stated : 



Alabama, 275 (Oberholser, 1909). 

 Ari:!ona, 371 (Cooke, 1914). 

 Arkansas, 2^^^ (Howell, 1911). 

 California, 541 (Grinnell, 1916). 

 Colorado, 403 (Cooke, 1912). 

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