276 Felger, Colorado Water Birds. [j$ 



I present herewith a detailed map containing measurements person- 

 ally made. These measurements represent in each case the size 

 of the body of water at the average high water line. They are not 

 assumed to be absolutely accurate, but sufficiently accurate for all 

 ornithological purposes. In taking these measurements I first of 

 all established base lines, then with the aid of a compass I pro- 

 jected upon these base lines the points marking the extreme limits 

 of the lengths and breadths of the several lakes, and stepped off 

 the distances between these projected points. The extreme points 

 of the lakes having thus been established, I sketched in their out- 

 lines as best I could from observation while on the ground. 



I have included in these notes the earliest and latest dates known 

 to me, of the occurrence of the various species within or adjacent 

 to this area. It is not to be presumed that these dates represent in 

 all cases the extreme periods in which specimens may be found; 

 they are given to serve as a basis for future observations. 



Realizing the value to the ornithological student in his field work 

 in any given area of being familiar with the records of species not 

 yet discovered in said area, but noted in adjoining areas, I have 

 deemed it advisable to introduce herein an hypothetical list with 

 notes appertaining thereto. 



I have aimed to give proper credit where due by adding the name 

 of the informant wherever a record not my own is used, and I 

 desire in this connection to express my gratitude to those whose 

 names are herein mentioned, for helpful notes. 



[1. .ffichmophorus occidentalis. Western Grebe. — Straggler, rare 

 in adjoining and near-by areas. (Oct. 25-Nov. 9.) A western species 

 found only six times to date east of the range in Colorado: at Sloane's, 

 Marston's, and Tynon's lakes near Denver, reported by H. G. Smith (Nid., 

 Ill, 1896, p. 48.); at Sheldon's Lake, near Fort Collins, reported by W. W. 

 Cooke (Birds of Colo., p. 191); at Citizen's Lake, near Denver, reported 

 by A. H. Felger (Auk, XXVI, 1909, p. 86). From these near-by records 

 it seems probable that this species will yet be found in the area covered 

 by this article.] 



[3. Colymbus auritus. Horned Grebe. — Migrant, very rare in near- 

 by area. (Oct. 8, only date known.) Only three apparently unquestionable 

 records to date for the eastern slope of the State, one at Fort Lyon, the 

 other two at Golden. (Birds of Colo., pp. 49, 155.) All these birds were 

 observed at points south of this area, and since it is a northern species 

 coming south in the winter, it should be found here.] 



