COUES ON BIRDS OF DAKOTA AND MONTANA. 



List of specimens. 



597 



CALAMOSPIZA BICOLOE, [Towm:) Bp. 



Lark Bunting. 



The apparent absence of this species from the E,ed River region, with 

 its abundance on the Missouri, is one of the strong marks of difference 

 in the fauna of the two watersheds. It is an abundant and characteristic 

 species of the sagebrush country of the Upper Missouri, and extends 

 thence to the Rocky Mountains through the Milk River region. Speci- 

 mens were taken soon after leaving Fort Buford, and others at various 

 points to the headwaters of Milk River. The bird is rather a late 

 breeder, unless the eggs found July 9 and 21 were those of a second 

 brood, which is probable, since at no time did I hear the mating song 

 of the males, or witness the singular aerial excursions which mark the 

 same period of the bird's life, like those of the Yellow- breasted Chat. 

 The earliest male specimens procured were already in worn and faded 

 plumage. The eggs are four or five in number, measuring 0.80 to 0.95 

 in length by about 0.65 in breadth ; they are pale bluish-green, like those 

 of Sialia, and normally unmarked, though occasionally sparsely dotted. 

 Two Cowbird eggs were found in one of the nests secured. The nest is 

 sunken in the ground, so that the brim is flush with the surface, and is 

 built of grasses and weed-stalks, lined with similar but finer material. 



List of specimens. 



