BROWN-CAPPED ROSY FINCH 375 



The nest may be placed in a blowhole or shallow crevice only a 

 few inches within the cliff face, or it may be far back in a larger crack 

 beyond arm's reach. Less frequently it is built behind or under a 

 large rock amid finer detritus. One nest was discovered in a de- 

 pression on the surface of a cliff protected by a large overhang of the 

 escarpment. The nests always appear to be from 6 to 40 feet above 

 the top of the talus slide at the base of the cliff. These sites provide 

 shelter from the frequent blustery winds, rain squaUs, lightning storms, 

 and occasional snows that strike the alpine meadows during summer. 

 All the nests so far discovered appear to have been hidden in 

 perpetual shadow, entirely out of reach of the sun's rays. Niedrach 

 photographed parent birds feeding young in a nest on a shelf of rock 

 15 feet back in a cavelike opening that was so dark he could not 

 cast light on the nest itself even with the aid of mirrors. Such sites 

 must be very cold, especially at night. One nest on Mount Bross was 

 frozen tightly to ice formed by the congealing of water trickling down 

 during the frigid hours of darkness. 



The nest consists of a cup of fine material tightly woven into an 

 outer matrix of alpine moss {Sphagnum). Lincoln (1916) describes 

 it thus: "The bulk of the nest was of dry grass and flower stems 

 neatly and compactly woven together with a considerable quantity 

 of fine moss, and lined with a fine yellow grass and a few feathers 

 from the bird's body, with one White-tailed Ptarmigan feather. 

 It rested well into the silt which covered the bottom of the hole, 

 and the cup was placed to one side, thus giving walls of unequal 

 thickness on two sides. This inequality did not, however, change 

 the general exterior shape, which is practically round * * *." 



A nest collected by A. T. Wheeler, now in the University of Colorado 

 Museum, is practically circular, both exteriorly and interiorly, but 

 the sides of the cup flare outward below the rim so that the cavity 

 is wider inside than at the top. Lincoln's nest was 4.75 inches in 

 diameter, with an overall depth of 3.00 inches; the cup was 2.50 

 inches in diameter and 1.60 inches deep. A nest in the University 

 of Colorado Museum measures 5.69 inches in diameter and 2.81 inches 

 in overall depth; the rim of the cup is 2.37 inches in diameter; the 

 widest interior diameter is 2.75 inches; and the depth is 1.62 inches. 

 A third nest, in the Chicago Natural History Museum, of which 

 only the cup has been preserved, has the following dimensions: inner 

 diameter of rim, 2.60 inches; greatest inside diameter, 2.75 inches; 

 inside depth, 1.5 inches; overall depth, 2.50 inches. 



The outside of the nest appears always to be solely of alpine moss. 

 The cup is firmly woven into this matrix, the bowl composed of very 

 fine grasses, flower stems, and rootlets, the rim of slightly coarser 

 grass stems, and the underside of the cup, hidden by the moss, of stiU 



