374 U.S. NATIONAL JVIXJSEUM BULLETIN 23 7 paet i 



occasional song in flight is heard, and the characteristic call that birds 

 of both sexes give on the wing as they fly directly between the feeding 

 and nesting grounds. He found flocks of 10 to 15 individuals together 

 just before the nesting season, but during the nesting period the birds 

 were observed singly or in pairs. Where several nests are in fairly 

 close proximity, as on a single side of a peak, a number of individuals 

 may be seen at one time in a limited area. At Rocky Mountain 

 National Park I noticed that rosy finches did not occur in flocks 

 during the nesting season. 



Nesting. — The brown-capped rosy finch nests at elevations above 

 12,000 feet throughout the western half of Colorado and extreme 

 northern New Mexico wherever alpine tundra, precipitous cliffs, 

 talus slides, and slow-melting snowbanks combine to form the requisite 

 ecological conditions. The species probably nests also along the 

 Colorado border in Utah and Wyoming where a similar habitat exists, 

 but evidence of this is lacking. 



Despite the species' abundance in many parts of its range, very few 

 nests have been studied or collected. F. C. Lincoln (1916), reporting 

 the discovery of the first known nest by H. R. Durand, A. H. Bums, 

 and himself, writes: 



The nest was discovered July 11, 1915, on the southwest exposure of the south 

 peak of Mt. Bross, Park County, Colo., at an elevation of 13,500 feet, or within 

 600 feet of the summit, the elevation of Mt. Bross being 14,000 feet. This 

 altitude of the nest site here marks the limit of plant growth, the remaining 

 600 feet being bare rock, either slides or in the form of outcropping or small 

 cliffs. 



It was in one of these latter that the nest was found * * *. The face of this 

 cliff had suffered considerably from erosion, resulting in "chimneys" and cavities 

 from a few inches to several feet in diameter, and in one of the smaller of these 

 the nest was placed. The hole, forming the upper terminus of a vertical crack, 

 ran back twelve or fourteen inches and was about forty inches [sic] from the 

 base of the cliff. 



A number of nests from Mt. Bross were studied and added to the 

 collection of W. C. Bradbury. About these nests, F. W. Miller in 

 1921 writes: "On Mount Bross, the rosy finch is abundant everywhere 

 above timberline, though it nests exclusively on the southwestern 

 or Buckskin side at an altitude of 12,000 feet up. This locality is 

 ideal, the entire side of the mountain being one huge rock slide, 

 varied and broken with clifts and outcrops * * *, AU the nests 

 were found in clifts; one was placed on a shelf of rock in a prospect 

 tunnel. The usual site is in a hole or crevice in the face of a sheer 

 rock cliff. Where the rock is in lime formation, the nest is occasion- 

 ally placed several feet back in a narrow fissure. No nests or signs 

 of nests were found in the rock slides." 



