1122 U.S. NATIONAL MUSEUM BULLETIN 23 7 pakt 2 



1958-59. Not one of these birds was reported during the three sum- 

 mers, 1958-1960, though several observers watched for the colored 

 bands west of Boulder and in Rocky Mountain National Park 20 to 40 

 mUes northwest. This suggests that the birds migrating through or 

 wintering at Boulder breed some distance farther north in Wyoming or 

 extreme northern Colorado. 



J. c. dorsalis has more of a vertical than a horizontal migration, and 

 few birds move any great distance outside the pine forest of the breed- 

 ing range. H. S. Swarth (1924b) vmtes from northern Arizona: "One 

 specimen was collected in juniper woods September 28 * * *. This 

 was the only occasion on which dorsalis was seen below the yellow 

 pine belt. When the migrating northern juncos arrived, the mixed 

 flocks of caniceps, shufeldti [probably montanus (Miller, 1941b)] and 

 others were abundant at the lower edge of the pines and in the piilons 

 and junipers, but no specimen of dorsalis was found in any of these 

 aggregations. I found dorsalis at a higher altitude, in small flocks, 

 and never accompanied by any other species." A. R. Phillips 

 (Phillips, Marshall, and Monson, 1964) says dorsalis "* * * seems 

 a fine example of an altitudinal migrant, at first glance. During 

 severe winters, at least, it occurs commonly in the Verde and upper 

 Gila Valleys * * * just below the MogoUon and Natanes Plateaux. 

 It is notable, however, that these valleys lie to the south of the breed- 

 ing range. * * * the available evidence indicates that these birds 

 move downward in a southerly dnection only." 



In summarizing his account of the raising of three broods of dorsalis, 

 Hargrave (1936) comments on fall behavior: "* * * (6) that shortly 

 after leaving the nest the young of all but the last brood moved out of 

 the nesting territory; (7) that the third and last brood remained within 

 the nesting territory until the postjuvenal molt was nearly completed; 

 (8) that the parents apparently left the nesting territory together and 

 ahead of their offspring of their third brood ; (9) that, after the summer 

 adults had left, the young of the third brood remained and mixed with 

 others of their race; and (10) that the members of the third brood 

 apparently left the nesting territory together after the fall migration 

 was well under way." The young of the second brood left the nesting 

 territory August 3, 1935. The first birds from outside were trapped 

 September 10 and 11, "indicating that the fall movement was under 

 way." The next season, Hargrave and A. R. Phillips (MS.) noted 

 that dorsalis juveniles became numerous at Flagstaff August 15, 

 nearly 4 weeks earlier than the preceding year, but no adults were 

 seen at that time. 



Winter. — While in general the northern gray-headed juncos, 

 caniceps, move downward and southward for the winter, a consider- 

 able number winter in the mountains, well into the Canadian Zone in 



