ego) KEY TO THE BIRDS OF EASTERN NORTH AMERICA. 
Group 5. Wing, 15 to 17 inches long. 
Section 1. Second primary, longest; only first primary, 
emarginate, or notched. 
Duck Hawk. 
Length, under 19° primaries. dark brown, banded on inner web with pale rufous. 
Duck Hawk. 
Falco peregrinus anatum. 
See No. 291. 
Length, over 19; under tail coverts, white, without spots. 
White Gyrfalcon. 
Falco islandus, and races. 
See No. 286. 
Length, over 19; under tail coverts, marked with dusky or spotted. 
Gray Gyrfalcon. 
Falco rusticolus. 
See No. 287. 
