7 
by three specimens in our collections (the nestlings mentioned before from 
near Red Deer, Alberta), which are assuming a practically complete dark 
plumage. It is notable that four supposedly breeding birds collected near 
Belvedere, 60 miles northwest of Edmonton, on the edge of the northern 
spruce forest, are almost pure borealis and that no marked calurus char- 
acters have been noted in the summer birds of that neighbourhood, even 
by Mr. A. D. Henderson, who has had long experience with the raptores 
of that locality. 
Along the southern edge of these prairie provinces many specimens of 
distinct krideri type occur with the predominating borealis. There are 
nesting krideri with the young belonging to them, from Oak Lake, Manitoba 
(Plate II, figures 6, 7), and from various points along Red Deer river below 
Red Deer, Alberta (Plate I, figure 15; Plate III, figures 3, 4). A juvenile 
in the collection of Mr. Hoyes Lloyd, taken from a family group with the 
parents still in attendance in Riding mountains, Manitoba, is also strongly 
krideri. Harlani is common during a short period in spring and autumn, 
through Manitoba, where it has been noted in numbers and collected by 
Hamilton M. Laing and C. G. Harrold. Autumn flights are also reported 
by H. V. Williams (1926) at Grafton, North Dakota. At Belvedere, 
Alberta, H. M. Laing and C. G. Harrold noted considerable numbers 
passing over during September, 1926. We have juvenile specimens, 
that may be this form, taken at similar dates at and between these various 
stations. 
In British Columbia well-marked calurus predominates. The normal 
bird there runs consistently darker than breeding prairie specimens, with 
heavy abdominal bands and much rusty red in the light parts (Plate II, 
figure 8, is typical). The tail is usually decidedly banded in the adult, 
and melanotic specimens are comparatively common. Mixed with these 
are occasional birds of stronger borealis type, but the writer has never seen 
any from there whose identity was very doubtful. These heavily marked 
birds extend northward an unknown distance into the Yukon. 
Near the northern boundary of British Columbia a strange and 
complicated condition exists. In the neighbourhood of the Alaska, Yukon, 
and British Columbia boundary intersection calurus , krideri, and harlani 
are inextricably intermixed, breeding together and throwing both pure and 
mixed strains. At Atlin lake, Brooks and Swarth took eight harlani , 
of which one juvenile is accompanied by a parent. The other parent was 
seen and its general characters noted, but it was not taken. These birds 
vary between complete melanism and a condition rather whiter in body 
than Plate III, figure 3 (Swarth, 1926). 
Of the Red-tails of this region, Allan Brooks (1927) writes: “The 
ordinary type of Red-tail (pale-coloured calurus ) was seen by me in the 
heart of the breeding range of i harlani > at least seven times. In fact I 
suspect that a pair of typical red-tailed birds were breeding only a few 
miles from our quarters at Atlin.” 
No. 2664, Wilson creek, Atlin, June 19, 1914, an adult calurus, is in the 
Provincial Museum, Victoria, B.C. This bird is described in detail by 
Mr. Swarth (loc. cit.). It is fully melanotic, but with light-barred tail 
(Plate I, figure 23). In the L. B. Bishop collection there is also a calurus 
(4349, Lower Laberge, Yukon river, July 17, 1899) almost duplicating 
Plate III, figure 2. 
