174 



THE BIRDS OF COLORADO. BY ROBERT RIDGWAY. 



THE present paper is based upon the observations of Mr. Charles 

 E. Aiken, made in El Paso county, Colorado, chiefly in the vicinity of 

 Fountain.* The results of this gentleman's explorations in that field 

 were communicated, from time to time, to Professor Baird, Dr. 

 Brewer and myself, for use in our forthcoming work on North Amer- 

 ican Birds ; but they are of such great interest that we cannot 

 refrain from giving the public the benefit of them sooner than their 

 appearance in our work. 



In a paper on the birds collected by Mr. C. H. Holden, Jr., in the 

 .southern part of Wyoming,! Dr. Brewer has incorporated some notes 

 furnished by Mr. Aiken upon the birds observed by him in the con- 

 tiguous portions of northern Colorado ; but Mr. Aiken having since 

 sent to me a list of all the birds obtained and observed by him within 

 the limits of the latter Territory, I have availed myself of his list as 

 a nucleus for preparing a catalogue of all the species known to have 

 been found within its limits. A few additions to Mr. Aiken's list have 

 been made from Mr. Allen's "Ornithological ReconnoissanceJ" of por- 

 tions of Colorado, and from the collections made by the Government 

 exploring parties under the direction of Dr. F. V. Hayden, U. S. 

 Geologist, each species so included having the fact properly noted. 



Mr. Aiken's researches were attended by many very important re- 

 sults. A new snowbird (Junco hyemalis, var. Aikeni RIDGWAY, Am. 

 Nat., vol.vii, No. 10, Oct., 1873, p. 615), with two white bands on the 

 wing, and of much larger size than the common form, was found 

 among the high peaks and valleys of El Paso county ; and two 

 specimens of Centronyx Bairdii were taken in the same locality, being 

 the second and third examples that were then known. These speci- 



*See American Naturalist, vii, No. 1, p. 13. " A Glimpse at Colorado and its 

 Birds. By C. E. Aiken." 



t Notes on the Birds of Wyoming and Colorado Territories. By C. H. Holden, 

 Jr; with additional memoranda by C. E. Aiken. (Edited by T. M. Brewer, M.D.) 

 Proceedings of the Boston Soc. of Nat. Hist., vol. xv, pp. 19J-210 : Dec., 1872. (142 

 species.) 



J Notes of an Ornithological Reconnoissance of portions of Kansas, Colorado, 

 Wyoming and Utah. By J. A. Allen. Bulletin of the Museum of Comparative 

 Zoology, Cambridge, Mass., vol. iii, No. 6. Part iii. List of Birds observed at the 

 eastern base of the Rocky Mountains in Colorado Territory, between Colorado City 

 and Denver, in July and August, 1871; with annotations, pp. 147-153. (81 species.) 

 Part vi. List of Birds observed in South Park, Park County, Colorado Territory, 

 in July, 1871; with annotations, pp. 153-159. (54 species.) Part vii. List of 

 Birds observed in the Vicinity of Mt. Lincoln, Park County, Colorado, from July 

 19 to July 26, 1871 ; with annotations, pp. 159-164. (36 species ) 



