- Robert “Bob” Ricklefs, who died on June 7th, a day after his 83rd birthday, helped shape modern ecology through his work on birds, island biogeography, life histories, and biodiversity.
- His textbooks, Ecology and The Economy of Nature, introduced generations of students to the field with uncommon clarity and breadth.
- He believed that careful observation and field experience remained essential to science, even as ecology became more model-driven and publication-focused.
- Colleagues and students remembered him as exacting, generous, independent-minded, and gentle in manner while firm in judgment.
At the mouth of the Carmel River, a teacher set up a spotting scope and let a boy look through it. The birds were the first thing he saw. The habit of looking came next. He saw that the world could be understood, though not quickly, and that its order did not reveal itself to those in a hurry. Later he would say he never recovered from that experience. The remark was light, but also true. A childhood near Monterey, with woods behind the house and the Pacific within walking distance, gave him the subject of his life.
Robert “Bob” Ricklefs, who died on June 7th, a day after his 83rd birthday, spent that life asking how living things came to be where they are, and why they lived as they did. He became one of the most influential ecologists of his generation: an ornithologist, biogeographer, theorist, teacher, author and member of the National Academy of Sciences. His textbooks, Ecology and The Economy of Nature, shaped how thousands of students first encountered the field. Their authority came from clarity. He could take a tangled subject and find a usable path through it.
Birds were his beginning. As a boy he joined weekend outings with the local Audubon Society and gained the status, modest but real, of a child with a serious interest. At Stanford he briefly followed the spirit of the space age into engineering, then returned to biology. At the University of Pennsylvania he entered the circle of Robert MacArthur soon after MacArthur and E.O. Wilson had proposed the theory of island biogeography. The West Indies, birds and islands all seemed natural to him. They stayed with him, through Jamaica, the Caribbean, Panama, Antarctica and many other field sites.
He began with avian growth and development. His early work on bird life histories helped make development, energetics and reproduction subjects of evolutionary explanation. He asked why tropical birds often incubated eggs longer, why some species grew faster than others, and how trade-offs shaped life. These questions were biological, but they also suited the way he thought. They rewarded long looking. They did not yield much to haste.
Much of his later work had the same character. He returned to island biogeography after years away from it, helped develop and test ideas about taxon cycles, and argued that local communities could not be understood apart from the larger regions and histories that supplied them. He challenged ecologists to think less in terms of fixed places and more in terms of species, populations, movement, and time. In his final decades he pressed the role of pathogens and parasites in shaping communities. He could take a topic that seemed narrow, such as avian malaria, and use it to reopen a question many others had set aside.
He was also willing to dissent. He was skeptical of neutral theory, of overconfident models, of tidy accounts that outran the natural history. He did not treat data as ornament for theory. He thought observation could disturb theory, correct it and sometimes precede it. He worried that young scientists were being pushed toward rapid publication before they had mastered a place, an organism or a body of fact. “For ecologists, there is no substitute for working in the field,” he said. That was advice, and also a statement of method.
His manners softened the force of his opinions. In tributes published online, colleagues remembered him as courtly, generous, warm and sharp. He could challenge an idea without trying to wound the person holding it. His wit had an edge, but was seldom aimed cruelly. His wife, the botanist Susanne Renner, recalled a motto he had inherited from his father: suave in modo, fortiter in re—gentle in manner, firm in deed. It suited him.
He carried his distinction lightly. Awards came: the Wallace Award, major ornithological honors, the Ramon Margalef prize, election to the academy. He appeared to care more for the work than for academic apparatus. He was not a great pursuer of grants. He took on relatively few graduate students. He practiced, in an academic world of acceleration, a deliberate science: reading, thinking, writing, looking again.
This could make his mentorship demanding. Students were often given space before they knew how to use it. One former student called the lab “sink-or-swim,” then added that it taught independence. Another remembered that a visit to Ricklefs’s office rarely ended with answers. It ended with better questions. When that same student was hospitalized, Ricklefs visited more often than anyone outside the family. The detachment was intellectual, not human.
In 1995 he left Penn for the University of Missouri-St. Louis, partly so that he and Susanne could work in the same department. Later her career took her back to Germany, and the two spent years crossing the Atlantic. At retirement he said he most looked forward to being together again. Even then he did not intend to leave the department. He wanted to keep his office, advise students and remain among colleagues. “I’m not going to miss anything,” he said, because he would keep doing what he wanted to do.
That was the shape of the life. Curiosity did not dim. The boy at the spotting scope became the scientist who still believed that observation mattered, that nature had to be met before it could be explained, and that the best science left room for wonder disciplined by evidence. He leaves a plainer inheritance: that a large mind can be carried with restraint.
Banner image: Bob Ricklefs. Photo by August Jennewein
Citations:
- J. Viegas (2012). Profile of Robert E. Ricklefs, Proceedings of the National Academy of Sciences (PNAS). U.S.A. 109 (38) 15075-15077, https://doi.org/10.1073/pnas.1213178109.
- B. McGill (2026). Robert Ricklefs – in memoriam. Dynamic Ecology
- R. G. Gillespie (2011). Interview with Robert E. Ricklefs, recipient of the 2011 Alfred Russel Wallace award. Frontiers of Biogeography
- S. Walentik (2019). Noted ecologist and ornithologist Bob Ricklefs aims to remain involved at UMSL even after retirement. UMSL Daily.
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