170 



KEY TO THE BIRDS OF KASTEltN NOUTH AMERICA, 



Group 5. Wing, 15 to 17 inches long. 



Section 1. Second primary, longest; only first primary, 



emarginate, or notched. 



Duck HaM'k. 



Leugth, under 19- priniurioj. tlurk brown, banded on inner sveb with pale rufous. 



Duck Hawk. 

 Falco percgrinns (tnatum. 

 See No. 201. 

 Leugth, over 19; under tail coverts, wliite, without spots. 



White Gyrfalcon. 

 Falco islamlus, and races. 

 See No. 286. 

 Leugth, over 19; under tail coverts, marked witli dusky or spotted. 



Gray Qyrfalcon. 

 Falco rusticolns. 

 See No. 287. 



MMiii 



