Dr Robert Eric Ricklefs is an American ornithologist and ecologist. He is the Curators' Professor of Biology at the University of Missouri, St. Louis.

Born in 1943, he graduated with an Bachelor of Science from Stanford University in 1963 and a Ph.D. from the University of Pennsylvania in 1967. He completed a year as a postdoctoral fellow at the Smithsonian Tropical Research Institute before taking up a faculty position at the University of Pennsylvania. He was the 1982 recipient of the American Ornithologists' Union's William Brewster Memorial Award, the union's most prestigious award given annually for an exceptional body of work on birds of the Western Hemisphere. In 2003, he received the Pacific Seabird Group's Lifetime Achievement Award for his work on growth and development in seabirds. He was awarded the 2003 Margaret Morse Nice Medal by the Wilson Ornithological Society. He was the 2006 recipient of the Cooper Ornithological Society’s Loye and Alden Miller Research Award, which is given in recognition of lifetime achievement in ornithological research.