My candle burns at both ends;
It will not last the night;
But ah, my foes, and oh, my friends–
It gives a lovely light!
Edna St. Vincent Millay
The lovely light of the candle is synonymous with the lives of the bizarre and beautiful birds. One pathway of evolution has resulted in the male’s flamboyant colors, tempting ornaments, and loud love songs, all to impress the female, even at the expense of his survival. The other more conservative pathway has led to identical males and females of subtle camouflage coloration; the keep-your-head-down, blend in, and stay safe approach to life, with survival being the ultimate goal.
The conservative approach follows the classic science of evolution by natural selection and survival of the fittest, first described by Charles Darwin and Alfred Russel Wallace. Darwin, however, later decided that a different theory was needed to explain the evolution of beauty; a process resulting in the dramatic bright plumages, long tails, striking crests, and unusual courtship behaviors. The aesthetic evaluation of mate choice and pleasure become the goal of these birds, apparently trumping survival determined by the classic idea of fitness.
Richard Prum expertly describes the consternation and debate that Darwin caused in his lifetime over the concept of evolution by sexual selection, a debate that has lasted to the present. The author takes up Darwin’s fight and supports his argument with fascinating accounts of avian courtship, emphasizing the central role of the female choosing a mate purely for the pleasure of it. Detractors say that assigning charm, sensory delight, and aesthetic discernment to birds is far too anthropomorphic. Darwin and Prum disagree.
It was the elaborate beauty of the Peacock’s tail with its eyespots that was so unsettling to Darwin. How could his “Origin of Species” and survival of the fittest explain this impractical plumage? His second book, “The Descent of Man”, introduced sexual pleasure and female choice as new and different driving forces in evolution. As you can imagine, Victorian patriarchal England had significant issues with this revolutionary concept.
Prum has impressive credentials, first as a childhood birder from New England, then from years of fieldwork in the tropical jungles, and later as a professor of ornithology at Yale. In the chapter “Beauty From the Beast” he describes the male Bowerbirds and their construction of architecturally elaborate bowers or bachelor pads. These males build competing aesthetic structures which have no practical use other than to charm and attract a female mate. The evolving male animal artists must match the corresponding evolution of female preference for their art to be successful.
The fossil record raises some interesting ideas about the origin of colorful feathers. It seems that feathers evolved and adorned reptiles prior to other structural changes that would allow flight. Recently electron microscopy has shown tiny color-forming melanosomes in the feathers of the theropod dinosaurs. Were these early colorful feathers initially sexual ornaments that only later evolved to the avian structures of flight?
In the chapter “Manakin Dances” Prum describes the bizarre social world of South American Manakin leks. A lek is a small, male-defended patch chosen as his personal stage upon which he performs to lure females. The male, in turn, is chosen for mating by a discerning female who is impressed by his plumage ornaments, acrobatic displays, dancing skills, and acoustic signals. It is female choice that drives male behavior and sexual evolution.
So why do I give this book only 4 stars out of 5? To me the wheels seemed to come off a bit in Chapter 5, “Make Way For Duck Sex”. The description of the ducks’ displays, female and male urogenital tracts (males are endowed with a long retractile penis), and the description of copulation, both consensual and otherwise, were fascinating. But the author at this point begins to enter into a highly speculative correlation of avian behavior with human sexuality, including female autonomy, feminism, fashion, eugenics, and even homosexuality. Although these are worthwhile topics, the jump from avian evolution which occurs over millions of years to human sociology and cultural evolution, which may change yearly, seemed somewhat farfetched and out of place.
But this book will have great appeal for birders and non-birders alike. As I read other reviewers it is clear that birders favor the first half of the book and its wonderful accounts of avian behavior, while non-birders relish the second half which evolves into a parallel discussion of human sexuality and social issues. Clearly the book will foster many interesting discussions and I can picture it as a popular book club selection.
The next time I am traipsing through the underbrush and see the brilliant crimson flash of the male Cardinal, the iridescent body of the Hummingbird, or hear the loud melodic call of the Carolina wren, I’ll remember Darwin and Prum and the millions of years of sexual selection that have created pleasure for both the birds and the birder.