36 USE OF THE KEYS. 



Now let us take a somewhat less simple case a male English Spar- 

 row. This bird, you will doubtless remember, has a black patch on 

 the throat and breast, a slate-colored crown, chestnut marks on the 

 sides of the head, and a streaked back. Turning to the key to the 

 family Fringillidce, or Finches, Sparrows, etc., we read first the head- 

 ings to the main divisions which, in the larger families, are placed at 

 the beginning of the key in order that they may be more readily com- 

 pared. 



" I. Under parts with red. 



" II. Under parts with no red, and without distinct streaks ; throat 

 or breast sometimes with a patch or spot. 



" III. Under parts without red, and with numerous streaks." 



Our bird undoubtedly belongs in Section II. Under ,this section 

 we read first : " 1. Tail with white spots, bars, or patches." Our bird 

 has no white in the tail, so we go to " 2 " and read : '* Without large 

 white spots or patches in the tail." There is no number 3, so we have 

 no hesitation in placing our bird in Section " 2." The first subsection 

 here is " A. Back without distinct streaks." Our bird is unquestion- 

 ably streaked, and we therefore go to " B. Back distinctly streaked." 

 There is no Section (?, and it follows that our bird belongs in " B." 

 Under B we have " a. Bend of the wing yellow " and " b. Bend of 

 the wing not yellow." Our bird has no yellow on the wing, and we 

 therefore place it in subsection b. This subsection is subdivided 

 into " b 1 . Crown bright reddish brown," etc., " c 1 . Crown streaked or 

 spotted," etc., and " d l . Crown mixed grayish brown and rufous, ashy, 

 or slate-color, without black streaks." Evidently our bird belongs in 

 the group headed d l , which we find includes four species, d 9 , d 3 , d*, 

 and d*. After reading the characters assigned to each of these, we 

 have no hesitation in deciding that those under d* apply to our bird, 

 and we prove our identification by turning to the description of Passer 

 domesticus. 



I have purposely taken a comparatively complicated case. If I 

 have made it clear, you will have no further difficulty in using the 

 keys, so far as their construction goes. It might be supposed, from 

 this somewhat lengthy description, that the process required much 

 time ; but as you become familiar with the use of the keys it should 

 never take you more than five minutes to identify a bird with them. 



Descriptions of Plumage. The descriptions, with quoted excep- 

 tions, are from specimens in the American Museum of Natural His- 

 tory, and my thanks are due the authorities of that institution for 

 permission to use its valuable collections. I have tried to make them 

 as concise and simple and, at the same time, as detailed as seemed 

 necessary for the purpose of identification. 



