Florence Augusta Merriam Bailey (August 8, 1863 – September 22, 1948) was an American ornithologist and nature writer. She was born in Locust Grove, New York. The youngest of four children, she was the younger sister of Clinton Hart Merriam. She organized early Audubon Society chapters and was an activist for bird protection. She wrote what is considered the first bird field guide in the modern tradition, Birds Through an Opera-Glass, published in 1890.