1072 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 2 



soon notices the pink-sided Oregon j uncos, so named for the rich pink- 

 ish cinnamon of their sides. I believe they are the most common 

 birds in Yellowstone. 



Yellowstone is indeed junco country. The mixture of meadow and 

 pine affords much of the "edge" that all juncos favor. Most of the 

 undergrowth is not dense, but is open and grass-covered beneath the 

 pines. 



I have seen pink-sided Oregon juncos equally at home in the iso- 

 lated mountain ranges of southern Idaho, the high country near 

 Mount Borah which is the highest peak in Idaho, the dense forests 

 of aspen {Populus tremuloides) and Douglas fir {PseudoUuga taxifolia) 

 near Grand Teton National Park, Wyo., and the high mountains of 

 the Continental Divide along the Idaho-Montana border. Westward 

 through the Sawtooth Mountains mearnsi intergrades with montanus 

 and southward toward Utah and southern Wyoming this race hybrid- 

 izes with J. c. caniceps, the gray-headed junco. In its habits I detect 

 no significant differences from those of other related Oregon juncos. 



A. H. Miller (1941b) says that mearnsi tolerates drier forests than 

 shujeldti or montanus. Nevertheless an adequate ground cover of 

 grasses and small flowering plants must be available during the nest- 

 ing season. Wherever the ground cover is suitable, one is almost 

 almost certain to find nesting juncos, especially if there is water nearby. 

 In the Bannock Range, Bannock County, Idaho, for instance, the 

 slopes have much aspen interspersed with big-tooth sage (Artemesia 

 tridentata) and here and there a Douglas fir; each opening in the 

 aspen or "edge" not too far from water supports a pair of nesting 

 juncos. 



On the other hand, L. B. McQueen (pers. comm.) found juncos 

 nesting abundantly in the Lost River Range, Custer County, Idaho, 

 and not necessarily near water. The forest growth of this arid range 

 is open and park-like, with many "edge" situations, and a thick 

 ground cover of grasses under the trees. The forest is Douglas fir 

 and at higher elevations Engelmann spruce {Picea engelmanni) and 

 some limber pine {Pinus jiexilis) . Mountain mahogany (Cercocarpus 

 ledvfolius) is quite common on terraces and ridges not otherwise occu- 

 pied by the conifers, and McQueen observed juncos nesting in this 

 cover. The use of mountain mahogany by mearnsi is not reported 

 previously, although caniceps uses it often. McQueen found chipping 

 sparrows abundant in the same habitat as the juncos. In 1960 in 

 the Caribou Range, Bonneville County, Idaho, near the Wyoming 

 border, I found chipping sparrows more common than juncos in the 

 drier places in the forest, and seldom found juncos at any distance 

 from water, nor far from the "edge" of the denser growth. 



Spring. — M. P. Skinner (1920) says of the juncos in Yellowstone: 



