Background
He was a member of the AOU committee that prepared the original edition of the Check-List of North American Birds (1886), including the classification and nomenclature to be used. Coues explored in the West and Southwest, where he discovered new species of birds. The Coues' cactus wren and the Coues' flycatcher, both birds of the far Southwest, are named in his honor.
Coues was born in Portsmouth, N.H., on Sept. 9, 1842. In 1853 his family moved to Washington, D.C., where he developed an interest in ornithology through his associations with naturalists at the Smithsonian Institution. Coues was educated at Columbian College (later Columbian University and now George Washington University), from which he received his M.D. degree in 1863. In 1862, during the Civil War, he enlisted as a medical cadet in the U.S. Army. He was appointed to the position of assistant surgeon in 1864, and he retained this position until he retired from the Army in 1881. While in the service, Coues was sent to posts in the West, and there he was able to study and collect specimens of native bird life. In 1864, while stationed in Arizona, he discovered a then-unknown species of wood warbler, which he named Grace's warbler in honor of his sister. His discoveries of western birds so outdated previous ornithological works that he wrote his famous Key to North American Birds in 1867.
From 1873 to 1876 Coues served as secretary and naturalist to the U.S. Northern Boundary Commission. His observations of the bird life in the northern part of the country are contained in his book Birds of the Northwest (1874). Coues also studied North American mammals, and in 1877 he published Fur Bearing Mammals. In the same year he became a professor of anatomy at Columbian University, remaining at this position until 1886. While at Columbian, he began to write his classic Birds of the Colorado Valley (1878), which he never completed. In 1880 he became secretary and naturalist to the Geological and Geographic Survey of the Territories. Many of his important ornithological papers appeared in the bulletin of the survey. Between 1884 and 1891 he contributed to The Century Dictionary on the subjects of biology, zoology, comparative anatomy, and ornithology.
During the 1880's Coues became interested in psychical research and was active in the formation of the American Society for Psychical Research. He later disagreed with and denounced the society, which, in turn, expelled him in 1888. The society filed a libel suit against him in 1892, but the charges were dropped. Coues then turned to editing the journals of early explorers and travelers to the W. He published 15 such works in all; of these, the most widely read are Expedition of Lewis and Clark (1893) and Expeditions of Zebulon Montgomery Pike (1895). In 1899 Coues became ill while on a trip to the Southwest to gather information for his book Diary of Francisco GarcésGarces (published posthumously in 1900). He died in Baltimore, Md., on Dec. 25, 1899.