1104 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 2 



Some, probably most, dorsalis breed near the territory in which they 

 were raised. Hargrave (MS.) reports, also at Flagstaff, a female he \ 

 banded as a juvenile, Aug. 13, 1936, and which he beheved nested the 

 next year mthin 50 yards of the point of banding. The bird nested 

 there 2, 3, and 4 years after banding, and was last seen there in May of 

 the 5 th year, 1941. 



Recorded observations of territorial conflict between gray-headed 

 juncos are few. During population studies by the writer (Thatcher 

 1955a, 1955b, 1956) and others in three areas in the eastern foothills 

 of the Colorado Rockies, approximately 84 supposed territorial pairs 

 were observed during 5 breeding seasons, in or immediately outside 

 the study areas. Only one brief fight between two males of this species 

 was recorded, June 18, 1953. On May 12, 1952, two gray-heads, ap- 

 parently a pair in their nesting territory in open ponderosa pine, 

 attacked and drove off a migrating slate-colored junco. In the same 

 locality on Mar. 16, 1960 I attracted two gray-headed juncos and a 

 single J. 0. mearnsi with "tic" notes from a pewter-and-wood "bird 

 call." The gray-heads ignored the migrant mearnsi but presumably 

 regarded the bird call as a rival. 



Louise Hering (1948) found five pairs of caniceps beheved to be 

 nesting on a 75-acre study plot in the Black Forest of Colorado. 

 She reports: "Three pairs of juncos were far separated on the tract, 

 while two breeding pairs remained near each other thioughout the 

 season. The males of the latter two pairs sang rather often but both 

 famihes fed on the forest floor without any apparent territorial con- 

 flict." A. C. Twomey (1942) in Utah took a female hybrid caniceps- 

 meamsi "from a nest * * * within forty feet of a nesting pair of 

 camceps." 



Courtship. — The matmg behavior of the gray-headed junco probably 

 differs Uttle, if at all, from that of the better known Oregon and slate- 

 colored juncos. Twomey (1942) wrote of our species in Utah during 

 the nesting season: "The birds at that time could be heard singing 

 from aU corners of the forest. The male always chose the top of a tall 

 pine as a singing post. Considerable activity, consisting chiefly of 

 pursuit and nest-building, was observed here." 



Miller (1941b), in discussing hybridization between J. c. caniceps 

 and J. 0. mearnsi in northeastern Utah, describes interesting mating 

 behavior of some of the hybrids: 



A pair of birds about my camp west of Garden City was feeding young on July 22 

 [1931]. The male was collected at 5 a.m.; it was pure mearnsi on back and sides, 

 but with head intermediate. The female, which could be seen to have normal 

 mearnsi color on the sides and back, was left with the young. At 10 a.m. the small 

 young were in the same group of bushes with the female, and a new male was on 

 hand, singing, following her with tail fanned, and twittering with characteristic 

 mating behavior; she did not drive him away. This bird was taken and found to 



