GRAY-HEADED JTJNCO 1105 



have a mixed yellow back, nieamsi sides and intermediate head. Female X, as she 

 now became known, had another male attached to her party shortly after 11 a.m. 

 This male was mearnsi in all characteristics except for intermediate tone of head. 

 A fourth male came to female X at noon and proved to have pure mearnsi back, 

 pure caniceps sides, and intermediate head. I am doubtful that these males were 

 all unattached previous to their interest in female X. Mjiles of various sparrowrs 

 are known to be polygamous on occasion. There was no doubt of the attraction 

 of the female for all of them, however. Not knowing the history of the case, an 

 observer would have considered each to have been her normal mate. No intoler- 

 ance was evidenced by the female. Some of the males gathered food for the 

 young. This indicates disregard on the part of the junco for differences in colors 

 of sides and backs. 



A^esting. — The graj-headed junco is with rare exceptions a ground 

 nester and is ordinarily the only such passerine within its usual 

 habitat, except the larger and much less plentiful Townsend's solitaire 

 (Myadestes townsendi) , whose nest is not likely to be confused with the 

 junco's. At timberline the junco's nest may be placed under a rock 

 like that of the Avater pipit (Antkus spinoletta) and the two may be 

 confused readily. Ground nests of the Wilson's warbler {Wilsonia 

 pusilla) and the Lincoln's sparrow {Melosyiza lincolnii) in wet places, 

 of the white-crowned sparrow (Zonotrlchia leucophrys) at timberline 

 and of the western flycatcher (Empidonax difficilis) in roadside or 

 stream banks might be confused with the junco's. 



Nesting activity commences as soon as most of the winter's snow 

 disappears, and often before the last heavy spring sno\\^alls. My 

 earliest observation of caniceps nesting activity in north central 

 Colorado was Apr. 28, 1954, when I (Thatcher 1954) saw one of a pair 

 carrying nest material near the upper limit of the ponderosa pine, 

 at 7,800 feet during a "warm, dry spring when breeding activity was 

 two to tlu-ee weeks earlier than usual." The earliest nest in the same 

 area had five eggs when I found it Maj'- 29, 1952, and young 3 days 

 later. Assuming 5 days for laying and 12 for incubation, the nest 

 was probably completed by May 15. 



The latest definite nesting acti\aty date is contributed by Louise 

 Hering (MS.) of two young that seemed "to be just out of nest" at 

 Grand Lake, Colo., at approximately 8,500 feet, Sept. 4, 1949. As 

 parental feeding of the young probably continues 18 to 20 days more, 

 the nesting period of caniceps in Colorado presumably extends through 

 a period of at least 21 weeks: AprU 28 to September 22. 



The May 29 caniceps nest mentioned above was at the edge of a 

 large opening in the pines on a slight southwesterly slope, hidden in 

 a shallow hollow beneath the downhill side of a clump of mountain 

 rauhley (Muhlenbergia montana), the major grass of the south-slope 

 pine forest. A heavy, 3-inch snowfall 6 da3^s before the nest was 

 discovered had no adverse effect on it. Three other nests found 

 nearby during 5 years of population studies were similarly located 



