BIRDS OF NOBTH AND MIDDLE AMERICA. 



13 



Young in second S'lriifner." — Upper parts gi'ayish, as in summer 

 adults, but superciliary stripe and under parts paler (dull pale buft'y 

 or dull butfy white) than in winter adults, the chest, sides, and flanks 

 conspicuously streaked with dusky, bill and feet blackish, as in 

 summer adults. 



Young in fi7'st autumn, and winter: — Similar to winter adults, but 

 upper parts decidedly brown and superciliary stripe and under parts 

 rather deeper brownish buff, with streaks on chest, etc. , less sharply 

 defined. 



Yoking, first plumage. — Similar to winter adults, but scapulai's and 

 interscapulars much darker centrally, the dorsal region being distinctly 

 spotted with dusky, pale superciliary stripe indistinct or obsolete; 

 streaks on chest and sides of lower throat blacker, usually heavier, 

 those on sides and flanks indistinct or obsolete. 



Adult maZe.— Length (skins), 140-160 (149.6); wing, 78-92 (86.1); 

 tail, 57.5-70 (64.7); exposed culmen, 11-13 (12.5); tarsus, 20.5-23 

 (21.7); middle toe, 13-15 (14.4); hind claw, 7-11 (8.9).* 



Adult female.— luength (skins), 135-155 (146.7); wing, 78-87 (81.9); 

 tail, 60-66 (62.2); exposed culmen, 11-13 (12.1); tarsus, 21-22.5 (21.7); 

 middle toe, 13.5-15 (14.4); hind claw, 7-11 (9.4). < 



« The species breeds in this plumage, which is very different from the fully adult 

 summer dress. 



6 Thirty specimens. 



"^Twenty specimens. 



Specimens from separate geographic areas (nearly all breeding birds) average, 

 respectively, as follows: 



Nearly all the specimens from Colorado, especially the females, were taken after 

 the middle of July, and have the primaries and rectrices much worn at ends; conse- 

 quently Colorado specimens in unworn plumage would show greater average length 

 of wing and tail. 



I am unable to make out any constant difference in coloration according to locality. 

 Possibly western specimens (including both the Kocky Mountain and Alaskan series) 

 average a little paler, with the chest more often unstreaked, or but slightly streaked, 

 than eastern, but the individual \ariation is so grfeat in exampk-.s from any locality 

 that I doubt the possibility of subdividing the specioM satisfactorily. 



