44 BULLETIN FERGUS COUNTY HIGH SCHOOL 



nest was about sixteen feet from the ground, made beside the main stem of 

 a small evergreen on the mountain-side. 



Distinguishing features: Upper parts ashy gray, lighter on the 

 head; wings and two middle tail feathers, black; other parts of wings and 

 tail, white; length 12-13 inches. 



494. BOBOLINK. Dolichonyx oryzivorus. 



A very common migrant, appearing about May 20, and lingering 

 two or three weeks in song. In the fall it is abundant in the weedy 

 borders of the stubble along the streams, where its metaillic "chink" can be 

 heard for several weeks in late August and early September. It is likely 

 that the bobolink breeds in suitable localities in the county. Messrs. 

 Richmond and Knowlton found the bobolink very common at one place 

 in the northern part of the Gallatin valley about the middle of August, 

 where a large number was observed in a rank growth of wild sunflowers 

 (Helianthus). In a considerable tract of nearly ripe oats nearby, they 

 found only a few stray birds. 



Distinguishing features: Back of head and neck, shoulders, rump, 

 and upper tail coverts, pale yellowish white; other parts black; length 

 about seven inches. The female lacks the whitish markings, and has up- 

 per parts streaked with brown and pale tawny. 



495. COWBIRD. Molothrus ater. 



The cowbird is not noticeably common in this region. It is not 

 often seen before the first week of May, but its shrill whistling call soon 

 announces its presence, and by the second week of May the cowbird is 

 well established in its haunts. As is generally well-known, this bird is 

 parasitic to the extent that its eggs are deposited in the nests of certain 

 other species, for the cowbird never makes a home of its own to rear its 

 young. Upon others, in whose nests its eggs are laid, is imposed the 

 burden of hatching its eggs and rearing its young, frequently to the utter 

 ruin of the family of the selected foster-parents. 



Brewer's blackbird is the chief victim of the cowbird in this locality. 

 I have found as many as five eggs of the parasite in a nest containing only 

 two eggs of the blackbird. Frequently the cowbird manages to deposit 

 the first egg in the finished nest. The yellow warbler also suffers very 

 generally from the impositions of the cowbird. Sometimes the little song- 

 ster prefers to cover over the cowbird's egg with its own, and thus avoid 

 the burden of caring for the alien. In the fall of 1900, I found two nests 

 of the yellow warbler in the rose bushes along Little Casino, which had 

 evidently served their purpose as homes of young warblers. Under the 

 soft bedding in each nest, however, two eggs of the cowbird were found 

 thus snugly covered. When the nests were finished, the cowbird had 

 found the snug cots before the owners had taken permanent occupancy, 

 and had deposited its eggs for the care of the warbler. The warbler, man- 

 ifestly unwilling to take upon themselves the care of the cowbird eggs 

 and younglings, had placed additional material over the eggs of the para- 

 site, thus defeating the purpose of the cowbird, while relieving themselves 

 of unwelcome aliens in their homes. 



