86 BULLETIN 17 0, UNITED STATES NATIONAL MUSEUM 



from any point whatsoever, and, so far as I am aware, no specimens of suckleyi 

 have been collected on the coast north of Vancouver Island. On the other hand, 

 migrants have been collected east of the Coast Range the entire length of British 

 Columbia. South-bound migrants collected by myself near Atlin, where the 

 form is not uncommon, were taken such a short distance south of the Yukon 

 Territory boundary as to make it obvious that suckleyi must breed in at least the 

 upper portion of the Yukon drainage. In the Atlin region, columbarius and 

 suckleyi occur in about equal numbers. Indeed, so far as I know, wherever 

 suckleyi has been collected typical columbarius has been found as well. Do not 

 these facts point toward the probability of the existence of two color phases of 

 Falco columbarius in the northwest rather than of two geographic races? Is 

 there, indeed, anything corroborative of geographic segregation of these forms?" 



Hamilton M. Laing (1935) evidently does not agree with the above 

 theory, and produces some evidence to indicate that the black pigeon 

 hawk is a good race and occupies a fairly definite breeding range in 

 the heavily forested coastal region of British Columbia and the 

 interior of Vancouver Island. 



FALCO COLUMBARIUS RICHARDSONI Ridgway 



RICHARDSON'S PIGEON HAWK 



HABITS 



This beautiful little falcon, the palest of the American merlins, is 

 a bird of the Great Plains, breeding mainly in southern Alberta and 

 Saskatchewan, in Montana, and in northwestern North Dakota. Its 

 summer home is on the wide rolling plains and prairies, where they 

 are dotted with small groves of poplars, aspens, cottonwoods, and 

 other deciduous trees. Prof. William Rowan writes to me that in 

 Alberta this falcon "breeds quite regularly, though not abundantly, 

 in the Edmonton district, in the Cooking Lake and the Sullivan Lake 

 districts, also on the Red Deer." He also thinks that it "breeds 

 farther north than is indicated in the Check-List, at least up to 

 Athabaska and possibly to the northern limit of the Canadian Zone." 



This falcon, when first discovered by Richardson, on the plains of 

 the Saskatchewan, was supposed to be identical with the European 

 merlin, which it somewhat resembles. Richardson's specimen, figured 

 in Fauna Boreali-Americana, plate 25, under the name Falco aesalon 

 was taken near Carlton House on May 14, 1827. Its distinctness from 

 that species was not discovered for many years, when Ridgway (1870) 

 described it as a full species and named it for its discoverer. Mr. 

 Ridgway (Baird, Brewer, and Ridgway, 1905) later decided to regard 

 it as a subspecies of columbarius, and it has so stood in the last two 

 editions of our Check-List. 



Spring. — T. E. Randall writes to me that Richardson's merlin, as 

 the bird was called for many years, is the first migrant to appear in 

 the spring in the vicinity of Castor, Alberta. His earliest record is 

 February 22, 1924, a male bird. "The bird is quite common by April 1. 



