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1 October 2012 What Were They Thinking? Is Population Ecology a Science?
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I admit that I love a good argument, not to mention a portrait of courage, and we get both in Bert's last book. In life Bertram G. Murray, Jr., was always challenging: I cannot remember a meeting or a phone conversation we had in which he did not have an intellectual ax to grind. He was singularly creative and demanding, and now all readers of the posthumously published What Were They Thinking? can take a look at some of the remaining questions from Bert's perspective. From the grave Bert's words appear, offering us a hand, speaking to those of us who ignored or failed to comprehend his work. So what if his tone is defensive—he had the courage to tell us what he thought. He reaches out to those of us who were not fair to his work and those who failed to openly criticize it. As Bert was dying, he resolved to speak after death even to those who dismissed his work as if it had not been done. Great credit for helping Bert achieve his goal goes to Joanna Burger and Joseph R. Jehl, Jr., who saw this book to publication months after Bert died.

I found Bert's papers, his rebuttals to anonymous critiques, and his philosophy demanding, just as he was in life, but also insightful: I learned a lot. By making sure that even his rejected papers were published, Bert showed his faith in the social, ethological aspects of science. You know: science is cooperative, and if our work remains unpublished, it's not science. I, for one, am sorrier than ever that I did not take more opportunities to know Bert's work while our colleague lived. He pleads with us to enter the fray of discussion and explain his errors: “My intention is to advance my science by having my views about ecological theory readily available for others to judge” (preface, p. viii).

Each chapter of Bert's last book is about something he was passionate about. The first chapter, “Philosophy,” is an introduction to what I consider exciting stuff. Here we glimpse the trailings of Bert's intensely intellectual life: it is a distilled primer of the great philosophers of science, particularly Popper, with whom all scientists should be familiar. I welcomed too the discussion of inductive and deductive hypotheses, and their conceptual differences and efficiencies that few of my new graduate students readily grasp. Could it be we're not teaching undergraduates the logic of scientific discovery? This chapter could be useful to those students. The second chapter, “Population Dynamics without Regulation: A New Equation,” reviews work from Murray's 1979 book and shows many results generated by a single, versatile equation that goes beyond the predictions of S-shaped population growth. The premise of Chapter 3, “Life-history Tables and Life-history Theories,” is that “life-history tables provide a foundational structure for testing life-history hypotheses” (p. 71), and from this came the study of clutch size in Prairie Warblers (Setophaga discolor; Murray and Nolan 1989) with its handy equation that uses other demographic parameters to predict clutch size. This equation, number 9, came out of Bert's “third law of evolution”:

Selection favors those females that lay as few eggs or bear as few young as are consistent with replacement because they have the highest probability of surviving to breed again, their young have the highest probability of surviving or both. (p. 99)

For me this law rings familiar because my own “compensation hypothesis” (2008, Journal of Evolutionary Biology doi:10.1111/j.1420-9101.2008.01559.x) says that females facultatively increase clutch sizes at an energy cost whenever their offspring are likely to suffer lower viability than other females' offspring. No, I didn't know about Bert's work. Like most readers, I was not familiar with his third law of evolution when I crafted my hypothesis. Nevertheless, the similarities make it easy for me to understand why Bert had pushback about his law claiming that females are going for replacement rather than maxed-out reproductive success. For some readers it is a counterintuitive idea. But both our ideas are testable using methods of experimental evolution in tractable model animals like Drosophila or even in birds, as he did with a population of Prairie Warblers. I believe Bert would be happy to know that a test of the predictions of his idea and an alternative is possible. Chapter 4 predicts the “Demography and Population Biology of Ivory-Billed Woodpeckers,” rejected from The Auk in 2006 and first published in this book. I cannot imagine why anyone would not be interested in a theoretical treatment of the life history of a potentially near-extinct species, for therein resides a “bold conjecture,” otherwise known as an “educated guess,” about the likelihood of their survival, and the news was not all bad. Chapter 5, “Clutch Size and the Length of the Breeding Season,” explains how his analytical solution to the problem of clutch size comes to predict what we frequently observe, namely that clutch sizes of passerine birds are smaller in the Southern Hemisphere than in the Northern Hemisphere. Chapter 6 takes up the math of the Mayfield method and Bert's responses to his critics. I have been interested for a long time in the lack of care and collegiality of reviewers in the face of “outside the box” authors. Here lies fodder for the historians of ornithology. Chapter 7 is a further discussion of the logic of scientific discovery. Henceforth, I will ask my graduate students to be familiar with it. Chapter 8 is about weighty issues of “mass” and “weight,” and this too our graduate students should read, and act accordingly.

With this review I invite you to read Bert's last book. All of us who take his advice and read him seriously will stand on Bert's scientific shoulders, and we will see farther than before.

© The American Ornithologists' Union, 2012.
Patricia Adair Gowaty "What Were They Thinking? Is Population Ecology a Science?," The Auk 129(4), 794-795, (1 October 2012).
Published: 1 October 2012

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