42 PACIFIC COAST AVIFAUNA. [No 4 



distribution at the different seasons, is that up to the end of March they 

 are fairly abundant between 5500 and 6500 feet, while but very few breed 

 at so low an altitude. They begin to pair off about the first week in 

 April ; on April 25 I shot a female which had laid part of its set, while the 

 latest nest I have seen was one containing three badly incubated eggs, 

 on July 30. The nest is usually built upon the ground, under a bunch 

 of grass, a log, or, as I have occasionally found it, under a flat stone ; but 

 this is not invariably the case, as I have known one or two instances of 

 its being placed in some thick shrubbery, a drooping pine limb, or a 

 young fir, a foot or two above the ground. The Arizona Junco is much 

 more arboreal in its habits in general than any other of the genus that T 

 have come in contact with, and on several occasions specimens were shot 

 from the topmost branches of the pines, fluttering about like warblers, 

 for which I mistook them, and from their actions apparently in search 

 of insect food. In the spring the male bird frequently ascends high in 

 the tree tops, and sits there motionless, uttering his short song at fre- 

 quent intervals ; and two or more may often be seen pursuing one an- 

 other through the trees, seldom descending to the ground at such times. 

 About the middle of June the young birds in the spotted plumage begin 

 to appear, and all through July they are quite numerous, often two or 

 more broods running together, accompanied by the various parents. 

 The young birds are at this time heavily streaked above and below, 

 though less on the throat and abdomen than elsewhere, the bill is uni- 

 formly black, and the iris brown. The dark streakings are confined 

 principally to the tips of the feathers, and, as the soft juvenile plumage 

 wears away very rapidly, those birds which have nearly attained their 

 full size have these markings much more faintly indicated than those 

 which have just left the nest. Specimens taken late in July, nearly ready 

 to discard the juvenile plumage, have the dorsum nearly uniform red, as 

 in the adults though much paler; and the dark streaks of the lower parts 

 restricted almost entirely to the upper breast. As the bird becomes older 

 the iris gets paler, changing from brown to whitish, then to pale yellow, 

 and finally, about the time the juvenile plumage is shed, to the bright 

 yellow of the adult bird. At the same time the lower mandible is grad- 

 ually becoming paler than the upper, the change in this respect as well as 

 in the iris, being completed about the time the adult plumage is assumed. 

 The juvenile plumage is shed in August, at tbe same time that the adults 

 are undergoing their post-nuptial moult ; specimens secured on Septem- 

 ber 2 being hardly distinguishable from adults, and wih but a few faint 

 spots remaining on the breast, sides of the head, and scapulars. The 

 scapulars seem to retain the juvenile markings the longest, and I have 

 one specimen, a female, presumably of the previous year, taken on April 

 4, in which not only the scapulars, but the greater wing coverts also, are 

 tipped with dusky, and there are one or two faint spots on the red of the 

 dorsum as well. An adult male taken September 2, has not quite 

 completed the moult, some of the rectrices having not yet acquired their 

 growth ; and is practically indistinguishable from specimens taken in 

 February, the principal difference being in the softer more blended ap- 

 pearance of the plumage. 



In the specimens collected there is some difference, mainly seasonal, 

 in the intensity of the red of the back, those taken in February and 

 March, having the color obscured by grayish edgings to the feathers. 

 In a number of cases there is more or less admixture of grayish in the 

 red of the scapulars and greater wing coverts, these parts occasionally 

 being almost entirely gray. In the tertials also there is considerable 



