James Cushing Merrill, military surgeon and naturalist, the son of James Cushing and Jane (Hammond) Merrill, was born in Cambridge, Massachusetts, on March 26, 1853. He received his early education at private schools in Cambridge and Boston and then went to Germany to begin his medical education. He returned later to the University of Pennsylvania, where he received his medical degree in 1874. In 1875 he was commissioned assistant surgeon in the United States Army and assigned to St. Louis Barracks, Missouri. His next assignment was Fort Brown, Texas, where from February 1876 to June 1878 he made observations and collections of the avifauna. His annotated list of 252 species was published as "Notes on the Ornithology of Southern Texas" in the Proceedings of the United States National Museum (1878).
Although the bird life of the lower Rio Grande valley had been studied by Jean Louis Berlandier, Henry Eeles Dresser, and the naturalists of the International Boundary Commission (later the International Boundary and Water Commission), it was still incompletely known during the 1870s. Merrill's study and that of George Burritt Sennett, which was published the same year, served to expand the observations of earlier naturalists and to draw attention to the unique avifauna of this region of Texas. Twelve species and subspecies of birds were recorded by Merrill as being new to the fauna of the United States. Most of the nests and eggs that Merrill collected were deposited in the National Museum, and many of the birdskins were given to his friend William Brewster at the Museum of Comparative Zoology at Cambridge. In addition to birds, Merrill also collected other zoological specimens, particularly insects.
After leaving Fort Brown, he was successively stationed at Fort Shaw, Montana, Fort Custer, Montana, Columbus Barracks, Ohio, Fort Klamath, Oregon, Watervliet Arsenal, New York, Frankford Arsenal, Pennsylvania, Fort Reno, Oklahoma, Washington, D.C., and Fort Sherman, Idaho. His important publications during this time included "Notes on the Birds of Fort Klamath, Oregon" (1883) and "Notes on the Birds of Fort Sherman, Idaho" (1897). In 1894 Merrill was made a full surgeon with the rank of major, and in 1897 he was appointed librarian at the surgeon general's office in Washington, a position that he retained until his death. He was a member of numerous professional organizations, including the American Ornithologists' Union, the Linnaean Society of New York, the Boston Society of Natural History, the Nuttall Ornithological Club, the Biological Society of Washington, the Washington Academy of Sciences, the Association of Military Surgeons, and the Association of Medical Libraries. His contributions to ornithology are memorialized by three subspecies of birds named in his honor: Merrill's pauraque, Merrill's song sparrow, and Merrill's horned lark. On November 16, 1892, Merrill was married to Mary Pitt Chase of Maryland. They had no children. He died on October 27, 1902, and was buried in Mount Auburn Cemetery, Cambridge, Massachusetts.