CLAEKE'S KTTTC BACKER. 423 



grasses and pine straw, forming a snug and comfortable structure. No hair or 

 feathers entered into the composition of any of these nests. The outer diameter 

 measures from 11 to 12 inches by about 7 inches in depth; the cup is from 4 to 

 5 inches wide and 3 inches deep. The quilted inner walls are fully 1£ inches 

 thick; it is quite deep for its size, and the female while incubating is well hidden. 

 Nest building must occasionally begin in the latter part of February, but more 

 frequently in March, and it appears to take these birds some time to complete 

 one of these structures. Both parents assist in this, as well as in incubation, and 

 the male is apparently equally as attentive and helpful as the female. While 

 they are noisy, rollicking birds at all other times, during the season of repro- 

 duction they are remarkably silent and secretive, and are rarely seen. The 

 eo-o-s, usually three in number but occasionally only two, are deposited during 

 March and April, according to locality, when the mountains are still covered 

 with considerable snow; incubation lasts, as nearly as I can judge, about 

 sixteen or seventeen days. The young are fed exclusively on hulled pine 

 seeds, and grow very rapidly, being able to leave the nest in about eighteen 

 days. Their plumage generally is much darker then than that of the adults, 

 and they are readily distinguishable. They follow the parents about for some 

 time, and when able to provide for themselves all these birds suddenly disappear 

 from the vicinity of their breeding grounds. This happens about the latter part 

 of May or early in June, and they are not seen again until fall, probably return- 

 ing to the higher mountains about this time. Only a single brood seems to be 

 raised in a season. 



The eggs of Clarke's Nutcracker are ovate and elongate ovate in shape. 

 The ground color is usually pale gray green, occasionally a clearer pale green. 

 They are rather sparingly flecked, spotted, and blotched with minute markings 

 of different shades of brown, gray, and pale lavender, usually heaviest about 

 the larger end of the egg, and these form sometimes a fairly defined wreath. 

 In others they are more evenly distributed over the entire egg, but never thick 

 enough to hide the ground color. In some the lower half of the egg is almost 

 unspotted. The shell of these eggs is close grained, smooth, rather thin, 

 considering their size, and slightly glossy. 



The average measurement of nine eggs, six of these only in the United 

 States National Museum collection, is 33.86 by 23.31 millimetres, or about 1.33 

 by 0.92 inches. The largest egg measures 34.80 by 22.86 millimetres, or 1.37 by 

 0.90 inches; the smallest, 33.78 by 22.61 millimetres, or 1.33 by 0.89 inches. 



The type specimen, No. 20384 (PI. 3, Fig. 22), from a set of two badly 

 incubated eggs, Bendire collection, was taken by the writer near Camp Harney, 

 Oregon, on April 8, 1878; No. 23683 (PI. 3, Fig. 23), is from a set of three eggs 

 collected near Gold Hill, Colorado, on March 5, 1888, by Mr. Denis Gale. 



