146 Birds of Colorado 



keeps to the heavy spruce timber most of the year. 

 It is a solitary bird, never forming large flocks, though 

 after the breeding season often seen in coveys or family 

 parties along the mountain meadows. During the 

 winter it remains in the thickest spruces, where it feeds 

 on the pine needles and buds, and where its presence 

 can often be detected by the debris collected underneath. 

 The food consists chiefly of vegetable matter, about 

 93 per cent, according to Judd ; this is mostly made 

 up of berries, especially those of the Kinnick-kinnick 

 (Arctostaphylos), and of pine needles, buds and flowers ; 

 the animal matter, about 7 per cent., is chiefly grass- 

 hoppers, taken at high elevations in the fall or late sum- 

 mer, when they are to be met with even above timber line. 

 In the spring especially the male makes a curious 

 booming or rumbling sound. It is said to most nearly 

 resemble the sound caused by whirling a rattan cane 

 round and roimd through the air. The production of 

 this sound is connected with the two naked patches on 

 each side of the neck. These are hollow vesicles in 

 connexion with the air sacs, and are inflated to the 

 size of half an orange at this time and are most con- 

 spicuous, while at ordinary times they are concealed by 

 the overlaying feathers. 



The nest, which has been described by Henshaw and 

 Burnett, is placed on the ground, generally in an open 

 glade, but sheltered or somewhat concealed ; that found 

 by Burnett was placed in a hollow under two old logs, 

 It is a simple structure of dried grass or pine needles ; 

 the eggs, eight or nine in number, are whitish to buffy, 

 with fine spots or dots of chocolate fairly evenly dis- 

 tributed. They average 2"0 x r40. Fresh eggs may 

 be looked for about the middle of June at the higher 

 elevations, earlier at lower elevations, according to 



