110 University of California Publications in Zoology [Vol.30 



(Swarth, 1922, p. 212). Bishop (1900a., p. 73) speaks of the red-tails 

 of the Yukon region (referred to B. i. calurus) as being in both the 

 light and the dark phase, about half of each, and of light colored and 

 dark colored birds breeding together. Nothing of the sort M'as seen in 

 the Atlin region, which may indicate that while Jmrlami alone occurs 

 in that section, it has a relatively limited range. I did see one pale- 

 colored bird, apparently krideri, near Gladys Lake, but this was on 

 September 7, when the southward migration was going on, and many 

 hawks were seen passing southward overhead. 



Both as regards different color phases and geographic variation, 

 the coloration of the Buteo horealis group (as well as of some other 

 species of hawks) is admittedly a difficult subject, and one that is 

 still far from being understood by any one. The most I can claim 

 for the facts here adduced is that they are corroborative of the idea of 

 Buteo horeicMs harlard being a geographic race rather than a "color 

 phase," such as is the darkest type of coloration seen in B. 6. calurus. 



These dark-colored Buteos were seen by us almost daily through 

 the summer and in all parts of the region that we visited. On May 

 21 several were observed soaring low over the snow-covered slopes on 

 the east side of White Pass. During the next week, at Carcross, they 

 were seen daily ; apparently several pairs were settled on their nesting 

 grounds near the town. 



About Atlin these hawks were distributed throughout the lowlands ; 

 there were nesting pairs at intervals of a few miles in whatever direc- 

 tion one traveled. Although the species was thus relatively numerous, 

 specimens were hard to obtain ; the birds were remarkably wary. 



The Harlan hawk is in the Atlin region mostly a bird of the timber. 

 The sort of perch most often chosen is the top of one of the taller 

 spruce trees, often in fairly dense woods but Eilways with such a com- 

 manding view as to make approach unseen out of the question. With 

 the exception of the dark colored hawks seen in White Pass early in 

 the season and supposed to be of this species, none was observed in 

 the open country above timber line. The abundance of ground 

 squirrels might have been supposed to be an attraction to that region, 

 too. They were extremely wary always, so much so that although 

 both birds of a pair might circle about, screaming, as long as an 

 intruder remained in their territory, it was generally impossible to 

 approach within gun shot. 



One nest was found. It was in the valley a few miles from Atlin, 

 in rather open spruce woods, just above a stretch of marsh laud. The 



