218 THE BIRDS OF MAINE 



c\ Upper tail coverts pure white. Marsh Hawk. (Im- 

 mature), 

 c*. Upper tail coverts not pure white. 



d'. Lesser wing coverts prominently margined with 



rufous. Red-shouldered Hawk. (Immatiure). 

 d". Lesser wing coverts not prominently margined with 

 rufous. Red-tailed Hawk. (Immature). 

 ??. Outer primary prominently or numerously barred with dark 

 bars, 

 a'. Wing under 10.00. 



b'. General color of back rufous. American Sparrow Hawk, 

 b*. Back not rufous. 



c'. Second primary longest ; back fuscous or bluish slate. 



Pigeon Hawk, 

 c*. Fourth primary longest. 



d'. Wing under 8.80 ; tail feathers nearly equal. Sharp- 

 shinned Hawk. (Immature), 

 d*. Wing over 8.80; outer tail feathers half an inch 

 shorter than the inner ones. Cooper's Hawk. 

 (Immature). 

 a*. Wing over 10.00. 



b'. Second primary longest. 



c'. First quill longer than third; tail under 9.00. Duck 



Hawk, 

 c*. First quill shorter than third ; tail usually over 9.00. 

 d'. Lower tail coverts pure white. White Gyrfalcon. 

 d*. Lower tail coverts more or less marked with dusky, 

 e'. Lower parts with dusky prevailing. Black Gyr- 

 falcon. 

 e*. Lower parts with dusky not prevailing. 



f. Top of head uniform dusky or with dusky pre- 

 vailing. Gyrfalcon. 

 f^ Top of head much streaked with white, or with 

 white prevailing. Gray Gryfalcon. 



(Note the Gyrfalcons are hard to tell apart, and this key is not satisfactory for distinguishing 

 the last three, but is the best I can do). 



b^. Second primary not the longest, either the third or 

 fourth longest, 

 c'. Upper tail coverts white. Marsh Hawk, 

 c*. Upper tail coverts not white. American Goshawk. 



(Immature). 



