“ He resigned from the army in 1881 to devote himself entirely to scientific research. He was a founder of the American Ornithologists’ Union, and edited its organ, The Auk, and several other ornithological periodicals. ”

“ He served as a medical cadet at Washington in 1862–1863, and in 1864 was appointed assistant-surgeon in the regular army. In 1872 he published his Key to North American Birds, which, revised and rewritten in 1884 and 1901, has done much to promote the systematic study of ornithology in America. In 1873–1876 Coues was attached as surgeon and naturalist to the United States Northern Boundary Commission, and in 1876–1880 was secretary and naturalist to the United States Geological and Geographical Survey of the Territories, the publications of which he edited. ”