16 
Plate I 
Central Tail Feathers 
Showing common variations in the principal subspecies of Buteo borealis 
Buteo borealis borealis 
Figure 1. 5652 d'&d. Detroit, Michigan, January 20, 1908. 
A rather richly coloured bird, tail without subterminal band. 
Figure 2. 14725 d”ad. London, Ontario, January 9, 1892. 
Not quite as warmly coloured a bird as preceding, but with suggestions of purplish reflections 
in blacks of back. Tail with usual subterminal band. 
Figure 3. 17323 9jv. Near Bathurst, New Brunswick, August 25, 1921. 
The common juvenile type. There is very little variation in the juveniles of this race. 
Buteo borealis calurus 
Figure 4. Hoyes Lloyd collection, cf? Armstrong, British Columbia, 1892. 
Completely melanotic, but with strongly red underparts and flags. Like Plate II, figure 8, 
but throat brown and the red below extending to undertail coverts. 
Figure 5, 54845 Univ. of Mich. 9 ad. Grafton, North Dakota, October 14, 1923. 
Melanotic, like type of calurus (Plate III, figure l), but with broad, decided red breast-band. 
The right, outertail feather departs widely from the rest. It looks as if the pattern and 
colour of figure 23 were superimposed on figure 17 with the subterminal band broken into 
harlani mottling. 
Figure 6. Walter Koelz collection, 9 ad. Bcntonville, Arkansas, Dec. 20, 1924. 
Melanotic. Body close to type of calurus, but slightly redder on breast. 
Figure 7. 10518 sex? nestling. Near Drumheller, Alberta, July 13, 1917. 
Light phase. Body like that of pure borealis, except for more heavily marked flags. This 
amount of red in the tail at this age is unusual in borealis and even in calurus seems rather 
evanescent, usually fading within a few' weeks after leaving the nest to a dull greyish brown. 
Figure 8. 3267 d’jv. Skagit river, British Columbia, August 3, 1905. 
Light phase, but body rather heavily banded with dark across abdomen and throat. 
Buteo borealis krideri 
Figure 9. 37635 (L. B. Bishop collection), d'ad. Hamilton, Kansas, Dee. 2, 1924. 
Body like a juvenile borealis, but with a noticeable admixture of w'hite on crown, nape, lower 
back, and wing coverts. 
Figure 10. 10503 (Acad. Nat. Sci., Phila.) ad?. Mississippi. 
Lower breast and abdomen almost clear w'hite, flanks slightly and faintly barred. 
Figure 11. 26382 (Acad. Nat. Sci., Phila.) sex?, ad?. Winnebago county, Iowa, August 30, 1879. 
Back almost half w'hite, crowai more than half white, and only a few dark shaft streaks and 
incipient bars on flanks. 
Figure 12. 6573 9 jv. Teslin lake, Yukon territory, September 3, 1912, 
In body almost exactly like Plate II, figure 2. 
Figure 13. 47154 (Univ. of Mich.). Clay county, Iowa, September 25, 1914. 
Flanks and abdomen with dark streaks and drops almost as in normal borealis, but head and 
neck three-quarters white, and much white on back. 
Figure 14. 16727 cfnestling, three-quarters grown. Oak lake, Manitoba, July 8, 1921. 
Body figured Plate II, figure 7. A borealis-looking bird identified as krideri by accompanying 
parent , also figured on same plate. Note red in tail. 
Figure 15. 10485 sex? nestling, three-quarters grown. Near Nevis, Alberta, July 9, 1917. 
Body figured Plate II, figure 4, almost identical with preceding and identified as krideri by 
accompanying parent, also figured. This parent is almost normal borealis, but with strongly 
marked krideri tail. Note lack of red in tail. 
Buteo borealis harlani 
Figure 16. 20521 (Jonathan Dw'ight collection) sex? ad. Portage la Prairie, Manitoba, April 14, 
1899. 
Melanotic. Body nearly entirely black, but breast and throat about one-third w'hite. Very 
little white on crown, nape, or face and none on scapular edges. Back lightly flecked with 
white. 
Figure 17. 55569 (Univ. of Mich.), d’ad. Grafton, North Dakota, November 17, 1925. 
Melanotic. Black deep, with little brownish. Throat and lower breast with considerable 
white. Undertail coverts and flags barred with ochreous rust. 
Figure 18. 20628 9 ad . Grafton, North Dakota, May 1, 1916. 
Similar to preceding, but black browner, and less white on throat and breast. 
Figure 19. Walter Koelz collection, efad. Pea Ridge, Arkansas, December 3, 1925. 
Almost solidly dark, rich brow'n. A few w'hite feathers on lower breast and a broken chin- 
spot. 
Figure 20. 19826 9 ad. Whitewater lake, Manitoba, April 2, 1925. 
An almost complete metano. A small, broken, w'hite patch on breast and a few T semi-concealed 
white streaks on throat. 
Figure 21. 20629 9 ad. Grafton, North Dakota, October 28, 1924. 
Light phase. Much white below and considerable on crown, nape, and back. More white 
than Plate III, figure 3, body much like ordinary juvenile borealis. 
Figure 22. 20394 cf nestling. Chitina River glacier, Alaska, near mount Logan, July 19, 1925. 
In full black phase, but with much ochreish feather streaks and edges on breast, flags, and 
elsewhere. Figured with parents, Plate III, figure 5. 
Figure 23. 2664 (Provincial Museum, Victoria, British Columbia), 9 ad, Wilson creek, Atlin, 
British Columbia, June 9, 1914. 
All deep, rich brown rather than black. Pale thumb-marks on wings. Slight, semi-concealed 
white streaks on nape. A few light flecks on breast and abdomen, those on breast tending 
towards ochre. An interesting bird, fully adult, as incoming tail feathers show the same 
pattern as the old ones. It has been identified by various good authorities as calurus, 
harlani, and even B. swainsoni. There is another almost exactly similar bird in the Koelz 
collection cf\ Bentonville, Arkansas, December 13, 1914, wdth the black extreme even for 
harlani, comparable to Plate III, figure 4, in this particular. The outer tail feathers of 
this Arkansas bird show strong harlani mottling. Note also final remarks under figure 5 
of this plate. 
