HOW TO USE THE KEYS 25 



Under the seasonal Heading, there are subdivisions accord- 

 ing to color, as already described, and in them the birds are 

 arranged in two groups, in the order of their size : Group A 

 contains birds larger than an English Sparrow ; Group B 

 those smaller than an English Sparrow. As a further help in 

 identifying the larger song-birds, the place in the list where 

 a Robin would come is indicated. If the student be in doubt 

 whether a bird be larger or smaller than an English Sparrow, 

 let him study the last birds in Group A, and the first in 

 Group B. If the bird be noticeably small, let him begin the 

 search at the bottom of Group B. The divisions A' and B' 

 are to be used only in southern Connecticut and in the lower 

 Hudson Valley ; the divisions A" and B" only in the north- 

 ern portions of New York and New England. An asterisk 

 beside the figures which give the size of a bird, indicates that 

 the bird does not occur every year ; two asterisks mean that 

 it is very irregular, and more often absent than present. 



The figures in the keys indicate in inches and decimals 

 the length of the bird ; the keys include, besides, a brief state- 

 ment of the kind of country in which the bird is generally 

 found, and brief clues for its identification, — some strik- 

 ing field-mark, or constant trick of action. If the bird has 

 been carefully watched under favorable conditions, the search 

 in the key will soon narrow down to a small number of spe- 

 cies. If there is still doubt, the descriptions of these species 

 and the accounts of their habits given in the body of the 

 book should be carefully read, the evidence weighed, and a 

 final choice, if possible, be made. A common fault of be- 

 ginners in identifying from printed descriptions is to ignore 

 some perfectly obvious and insuperable objection. I have 

 known the skin of a Brown Thrush labeled as a Cuckoo, in 

 spite of its spotted breast. Mr. Chapman tells me that the 

 Louisiana Water-thrush has been identified as the Olive- 

 backed Thrush : one is 6.28 inches long, the other 7.17; the 

 extra inch must tell, even in the field. 



