1922] Swarth: Birds and Mammals of the Stikine Region 297 



about eight or teu feet of their destination ; then they dropped to the 

 ground and hopped to the entrance. To the casual observer they dis- 

 appeared at a point some distance from the nest, and it was not until 

 they had been observed for some time that this subterfuge was detected. 

 The staple food that was being brought to the young was a small green 

 caterpillar infesting the poplars at that time; also a white grub, a 

 green katydid, and many mosquito-like insects. 



Thirty specimens were collected (nos. 40235-40264), six adults, 

 eighteen in juvenal plumage, and six in various stages of the molt from 

 Juvenal to first winter plumage. Two of the latter category, from 

 Great Glacier, August 12, have nearly finished the change. The birds 

 of this series, in color and size, exhibit the characters ascribed to the 

 subspecies septentriomdis, that is, as regards differentiation from the 

 eastern atricapillus. "Within the rather extensive habitat of septen- 

 trionalis there appears to be some variation in color, perhaps enough 

 to separate the Stikine River birds as distinguishably darker colored 

 than typical septentrionaUs. A few specimens at hand from the middle 

 west suggest this possibility, but there is not enough material available 

 to verify the supposition. The buffy coloration on the sides and flanks 

 appears to be an extremely evanescent character, conspicuously pre- 

 sent in the fresh fall plumage, but absent in breeding adults (in which 

 this same plumage has been subject to several months of wear). In 

 very young birds (nestlings) it is strongly apparent, but in juvenals 

 that could have been out of the nest no more than a month it has 

 almost entirely vanished. 



Penthestes gambeli abbreviatus Grinnell. Short-tailed Mountain 



Chickadee 



The limited opportunities we had for observation of this bird did 

 not suffice to demonstrate its ecological relationships with P. atrica- 

 piUus septentrionaUs. That is, as regards choice of local habitats of 

 the two — an interesting point where two such closely related species 

 of one genus occur in the same general region. SeptentrionaUs, as 

 previously remarked, strongly favors the poplar woods, and other 

 subspecies of the species atricapillus are known as denizens of 

 deciduous forests elsewhere. The species gamieli, on the other hand, 

 is largely an inhabitant of coniferous woods, and it seems likely that 

 in the Stikine region P. gamibeli atireviatus makes its summer home 

 amid the spruce and balsam of the higher mountain slopes, where we 

 never encountered P. atricapillus septentrionaUs. At Doch-da-on 



