EXPLANATION TO PLATE X. 



Fig. 1. Falco rusticolus obsoletus, Gmelin. Black Gyrfalcon. 



Figs. 2,3. Falco mcxicanus, Sohlegel. Prairie Falcon. 



Figs. 4,8. Falco columbarius, Linnasus. Pigeon Hawk. 



Figs. 5,6,7. Palco peregrinus anatum, Bonaparte. Duck Hawk. 



Figs. 9, 10. Falco tusco-coerulescens, Vieillot. Aplomado Falcon. 



Figs. 11, 12, 13,14, 15, 16. Falco sparverius, Linnaeus. American Sparrow Hawk. 



Pig. 17. Pandion haliaetus carolinensis, Gmelin. American Osprey. 



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