Robert Ricklefs

During his career, he has made major contributions to the island biogeography, including testing E. O. Wilson's Taxon Cycle Concept, His most-cited scientific paper examined ecological communities. Recent work has sought to rescale the concept of an ecological community. He has made major contributions to life-history theory of birds, avian growth and development, tropical ecology, and avian disease research. His original method for avian growth rate estimation continues to be used today though modifications have been proposed. His textbook Ecology, first published in 1973, continues to be updated and used in university courses. He has also published The Economy of Nature, Avian Growth and Development: Evolution Within the Altricial-precocial Spectrum and Aging, A Natural History.

Robert Eric Ricklefs (born June 6, 1943) is an American ornithologist and ecologist. He was the Curators' Professor of Biology at the University of Missouri, St. Louis from 1996 until August 2019.

Born in 1943, he grew up near Monterey, California, where his interest in biology was fostered by a teacher. He graduated with a Bachelor of Science from Stanford University in 1963 and a Ph.D. from the University of Pennsylvania in 1967. His doctoral advisor was originally Robert H. MacArthur (prior to his move to Princeton University), but he finished his dissertation under W. John Smith. During his PhD, he studied avian growth and development, which he continued for much of his career. He completed a year as a postdoctoral fellow at the Smithsonian Tropical Research Institute in Panama 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.