FALCONID^E. XLV. Ill 



fff. No ruff; 4 primaries emarginate; tail coverts white; tail 

 black. ASTUKINA, 9. 



/. FALCO, Linnaeus. FALCONS. 



* First primary only emarginate on inner web ; 3d longest, 1st 



shorter than 4th ; tarsal plates small ; sexes colored alike. 

 f Tarsus not longer than middle toe, scarcely feathered below 

 joint. (Falco.) 



1. F. communis, Gm. PEREGRINE FALCON. DUCK 

 HAWK. Blackish ash with paler waves; below whitish, 

 barred; black cheek patches; L. 16; W. 13; T. 7. U. 

 S., not common. 



tf Tarsus longer than middle toe and claw, feathered for some 

 distance. (Hierofalco, Guv.) 



2. F. sacer, Forst. GYRFALCON. Tarsus feathered 

 half way down, with only a bare strip behind; white or 

 ashy with dark markings; L. 24; W. 16; T. 10. Northern 

 regions of both continents; var. islanclicus, S. to U. S. 

 in winter. (F. gyrfalco, L.) 



3. F. mexicanus, Licht. LANIER FALCON. Tarsus 

 feathered way down; general color brown; L. 18; W. 

 14; T. 8. S. W., E. to Ills. 



** Two primaries emarginate t tarsal plates enlarged in front, 



appearing like scutella. 



\ Tarsus about equal to middle toe; basal joints of toes without 

 transverse scutella. (^Esalon, Kaup.) 



4. F. columbarius, L. PIGEON HAWK. AMERICAN 

 MERLIN. Ashy blue or blackish above, variegated 

 below; L. 13; W. 8; T. 5. U. S. 



\t Tarsus longer than middle toe; basal joints of toes with 

 transverse scutella. (Tmnunculus, Vieill.) 



5. F. sparverius, L. SPARROW HAWK. RUSTY - 

 CROWNED FALCON. Back tawny; wings bluish and 

 black; seven black blotches about head; tail chestnut, 



