28 



least no specimens of the true pallida type were taken, while the 

 other form was abundant, the sage brush plains seeming to be its 

 favorite haunts. 



43a. Spizella pallida var. Breweri Coues. Brewer's 

 Sparrow. 



A common inhabitant of the sage brush everywhere; especially 

 numerous in the valleys of the Yellowstone and Musselshell. 



44. Chondestes grammaca Bon. Lark Finch. 



One of the most abundant and generally diffused species, frequent- 

 ing the edges of the wooded bottom-lands and the bushy ravines, but 

 also found occasionally quite far out on the prairies. 



45. Calamospiza bicolor Bon. Lark Bunting. 



Very abundant at localities from near the Missouri to the valley of 

 the Musselshell. Prefers wet prairies and bottom-lands near streams, 

 where scores of pairs were sometimes found inhabiting a small area. 

 I have often seen six or eight males hovering and singing in the air 

 at once. Observed it first about fifty miles west of Fort Rice; saw 

 it in the valley of the Yellowstone the first week in August, in con- 

 siderable flocks, consisting mainly of young birds ; but it disappeared 

 entirely about the end of the month, being one of the earliest species 

 to migrate. 



In this species the colors are much less intense here than on the 

 plains of Middle Kansas and Colorado, the black being more ob- 

 scured by brownish edgings to the feathers, and more frequently 

 mixed with brownish patches. This region probably forms nearly 

 the northern limit of its distribution, it doubtless not extending its 

 range much to the northward of the Upper Missouri. 



The eggs of this species are very variable in respect to size, form 

 and depth of color. Some twenty sets were collected, varying in 

 color from pale bluish white to quite deej) blue. The average dimen^ 

 sions may be given as .90 by .73 of an inch, the variation ranging 

 from .80 to .95 of an inch in length, and .63 to .75 of an inch in 

 diameter. The considerable variation in form is indicated by the 

 following extremes of projections: .80 X -73, .95 X -65, and 

 .86 X -63. , The nest varies from a very slight to a quite bulky and 

 substantial structure. 



This species proves to be one of the favorite foster-parents of the 

 cow bird (Mohihrus pecoris). In a series of eighteen nests, five, or 

 nearly one-third, contained eggs of the cow bird, two even containing 

 two each, and one had three; while out of twenty-nine pests of 



