BIBLIOGRAPHY. 
This is a list of all the Titles up to December, 1910, containing 
anything of importance for the study of Colorado Ornithology. They 
are referred to throughout the text under the name of the author, with 
the abbreviated date only, 
72 Arxen, C. E., and Hoxpen, C. H., Jr. Notes on the Birds of 
Wyoming and Colorado Territories. Proc. Boston Soc. Nat. 
Hist., xv., 1872, pp. 193-210. This paper is edited by Brewer, 
and only the notes signed ‘‘C. E. A.,” contributed by Aiken, 
refer to Colorado. Mr Aiken spent the winter 1871-72 at 
Fountain, near Colorado Springs, and these observations were 
made at that time; some fifty-nime new birds are accredited 
to the State. 
73 AIKEN, C. E. A glimpse at Colorado and its Birds. Amer. Nat., 
vi., 1873, p. 13. 
73 Armen, C. E. A New Species of Sparrow. Amer. Nat., VIL, 
1873, pp. 236-7. Centronyx ochrocephalus (= C. bairdi) described. 
75 Arcen, C. E. The Nidification of the Blue Crow and the Grey- 
headed Snowbird. Amer. Sports., v., 1875, p. 370. 
00 Arcen, C. E. Seven New Birds for Colorado. Auk, xvir., 1900, 
p. 298. i., Gavia arctica, Ardea egretta, Syrnium nebulosum, 
Astragalinus tristis pallidus, Geothlypis agilis, Geothlypis trichas 
and Wilsonia canadensis. 
81 Armen, C. N. Songs of the Western Meadow-Lark. Bull. Nutt. 
Orn. Club., vi., 1881, p. 145-150. 
72 Auten, J. A. Notes of an Ornithological Reconnaissance of 
portions of Kansas, Colorado, Wyoming and Utah. Bull. Mus. 
Comp. Zool., mz1., 1872, pp. 113-183. This is an important 
paper for the history of Colorado ornithology. Mr. Allen was 
the first trained ornithologist to visit the State. He was in 
Colorado in July and August, 1871, chiefly near Colorado Springs, 
in South Park and on Mount Lincoln. Some eighty-four species 
were observed by him for the first time in the State. 
