MUSEUM OF COMPARATIVE ZOOLOGY. 153 



ARDEID^J. 

 80. Demiegretta ? sp. ? A single heron was seen on the South Platte, 

 apparently a Demiegretta. 



ANATIDiE. 



81.? Anas boschas. A single specimen of apparently this species was 

 observed at Summit Lake. 



VI. List of Birds observed in South Park, Park County, Colorado 

 Territory, in July, 1S71 ; with Annotations. 



South Park is an elevated plateau enclosed in the mountains of 

 Colorado Territory, occupying nearly its geographical centre. Its 

 average elevation is a little more than nine thousand feet, its area 

 nearly two thousand square miles. It is situated between the 35th 

 and 36th parallels, about fifty miles west of the eastern base of the 

 Rocky Mountains, and has a length of about sixty miles by a breadth of 

 about thirty. The surface of the Park is somewhat diversified, low nearly 

 parallel ridges running through it in a northwest and southeast direc- 

 tion, dividing it somewhat irregularly into a series of valleys, through 

 which flow the South Platte River and its tributaries. Most of the 

 ridges are scantily covered with pines and aspens, especially their 

 northern declivities, and the streams arc fringed with various species 

 of willow and cottonwood. The ''bunch grass " generally grows luxu- 

 riantly, especially in the vicinity of the streams, but considerable por- 

 tions of the Park are arid and alkaline, particularly to the eastward, 

 where the vegetation strongly resembles that of the more barren por- 

 tions of the plains. Here the prevailing plants are low artemisia-like 

 forms, rising to but a few inches, and a Utw species of Cactus. 



The avian fauna of South Park is far from rich in species ; the 

 greater part of which are woodland birds, the remainder being such as 

 typically characterize the Plains. During a reconnoissance of two 

 weeks in duly, only fifty-four species of birds were observed, many of 

 which were seen but once or twice, and less than half of which were 

 very common. Of the numerous family Sylricolidcz, but two species 

 were observed; of the Tyrannidce, only representatives of two cenora 

 [Contopns and Empidonax) ; while swimming and wading birds were 

 almost wholly absent. A few others occur in close proximity to the 

 Park, the most of which doubtless frequent to some extent the belts of 

 timber that intersect it. 



