14 THE PIGEON HAWK— MERLIN— " LITTLE CORPORAL." 



size, the species are easily separated by examining the tails. Both 

 sexes in F. colicmbarius have four distinct black bars — three ex- 

 posed and one concealed by the upper tail-coverts. In F. asaloii 

 the female only has the tail-bars distinct, and they are six in 

 number — five exposed and one concealed. The bars on the tail 

 of the adult male F. ccsalon, although six in number, are only 

 partially defined, and consequently very indistinct. The bill of 

 F. ccsalon is slightly more compressed laterally but not so much 

 so horizontally as that of F. coliimbarins. The tibia; in my adult 

 male specimens of the American bird [F. colmnbariiis) are darker 

 ferruginous, with narrower longitudinal lines than in my English 

 specimens of F. crsalon ; but this distinction may not be constant. 

 I had almost forgotten to state that the inner webs of the tail- 

 feathers of F. coliinibai'ius are white, except where crossed by the 

 black bars — in this respect diftering from F. ccsalon, which has 

 scarcely any variation in either web, both being bluish ash." Again, 

 in Coues' " Birds of the North-West," we find a distinct place 

 assigned to the Merlin, under the heading Falco RicJiardso)iii 

 (Ridgeway), American Merlin. To this bird he further gives a 

 defined habitat, namely, " Interior of North America, U. .States, 

 from the Mississippi to the Rocky Mountains, Arctic America." 

 Previous to the publication of the work just cited from, and in 

 1866, the same writer stated as follows : "In the immense series 

 of Pigeon Hawks which I have examined from all parts of the 

 West, I find a few specimens which constantly differ to a marked 

 degree from any of the diverse plumages in which F. colnvibariiis 

 presents itself. These specimens are invariably much larger than 

 any others in the series ; are much lighter colored, and differ con- 

 stantly in the increased number of light and dark bars on the tail. 

 Compared with a European specimen of F. ccsalon, they agree in 

 every particular. I think it most probable that future careful 

 research will demonstrate the existence of a species hitherto 

 usually confounded with F. columbariiis." We have found the 

 same resemblances and diversities in our collections of Canadian 

 specimens, but among these there are one or two which correspond 

 closely to that described as F. ccsalon in the Fauna Boreali-Ameri- 

 cana. Ridgeway, moreover, has detected some further differences 



