Florence Augusta Merriam Bailey (born Aug. 8, 1863, Locust Grove, N.Y., U.S.—died Sept. 22, 1948, Washington, D.C.) was an American ornithologist and author of popular field guides.
Florence Merriam was a younger sister of Clinton Hart Merriam, later first chief of the U.S. Biological Survey. She attended private school in Utica, New York, and during 1882–86 she was a student at Smith College, Northampton, Massachusetts; she did not follow a degree course at Smith but was later, in 1921, granted a B.A. Her interest in bird life was already well developed, and a series of articles she wrote for the Audubon Magazine were later collected in her first book, Birds Through an Opera Glass (1889).
Travel and dabblings in social work filled the next few years, but the onset of tuberculosis sent her west to convalesce. Her experiences in Utah, southern California, and Arizona bore fruit in My Summer in a Mormon Village (1894), A-Birding on a Bronco (1896), and Birds of Village and Field (1898). She then took up residence with her brother in Washington, D.C., and in December 1899 married Vernon Bailey, a naturalist with the Biological Survey. Thereafter they shared the life of field naturalists, her energy and enthusiasm enabling her to undertake expeditions on foot or horseback through mountains and across plains.
She continued to publish articles regularly and in 1902 produced her Handbook of Birds of the Western United States, a counterpart to Frank M. Chapman’s Handbook of Birds of Eastern North America. She also contributed to several of her husband’s books, notably Wild Animals of Glacier National Park (1918) and Cave Life of Kentucky (1933). She was a founding member of the Audubon Society of the District of Columbia and frequently led its classes in basic ornithology. She became the first woman associate member of the American Ornithologists’ Union in 1885, its first woman fellow in 1929, and the first woman recipient of its Brewster Medal in 1931, awarded for her comprehensive book Birds of New Mexico (1928), which she had begun under the auspices of the Biological Survey. Her last major written work was Among the Birds in the Grand Canyon National Park, published by the National Park Service in 1939.
A variety of California mountain chickadee was named Parus gambeli baileyae in her honour in 1908.