| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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Reviews Sauce for the Goose Promiscuity: An Evolutionary History of Sperm Competition, by Tim Birkhead. Harvard University Press, Cambridge, MA, 2000, 272 pp., $24.95 cloth. In Jane Austen’s Northanger Abbey, hero Henry Tilney argues that marriage and dancing are very similar, saying “You will allow that in both man has the advantage of choice, woman only the power of refusal.” This viewpoint remains familiar today. People believe it natural for males to disseminate their genes as widely as possible, and for females to remain faithful to one mate, limiting the fertilization of her eggs to his sperm. But in Promiscuity, noted ecologist Tim Birkhead shows that what’s sauce for the gander is also sauce for the goose. Females, he contends, are equally interested in maximizing the survival of their own genes. They may sneak in extra-pair copulations, selectively eject the sperm of males they later find less than appealing, or improve a male’s paternity success by mating with him at the peak of her fertility. Even eggs can get in on the action; color plates show two sperm that have penetrated a comb jelly egg. The nucleus of the egg first swims toward one sperm, looks it over, then turns to the second and, finding it to “her” liking, fuses with it. Promiscuity, Birkhead says, gives females a way to get enough good-quality, fertile sperm to ensure she will pass on her genes to strong young. Males have evolved equally cunning tactics in the battle of the sexes. Bedbug males stab females randomly in the abdomen to deliver their sperm, while some male wasps fertilize females even before they have emerged from their pupal cases. Baboon males bully their harem females into submission, while dominant purple martin males exercise droit du seigneur with the female partner of other pairs who move into their large apartment nests. A researcher assessed paternity in such a co-housing project and found that the dominant male had fathered 96 percent of the chicks in his own nest as well as more than half of the other chicks. But getting sperm in is only part of the story. Males have also developed a range of techniques to keep it there. Some grow large testes to produce copious sperm to drown out other males’ contributions. Others possess tools for scraping out semen from rivals, or plugging the female’s insemination canal. But the humble fruit fly may take the cake; his seminal fluid contains a cocktail of chemicals that includes an anti-aphrodisiac to discourage females from further matings, mixed with a poison that considerably decreases her lifespan. What does he care if she dies young, provided she makes him a father first? Birkhead sometimes fails to overcome his Western male conditioning, such as when he refers to dissenting women as “strident North American feminists.” And he forgets that daughters are just as necessary for expressing genes as sons when he claims females engage in promiscuity to ensure they will produce attractive sons who will in turn inseminate many females. But overall, he has written a thought-provoking, titillating, and often very amusing book that covers this racy topic with thoroughness and authority.
Two For the Birds Birds of North America, by Kenn Kaufman. Houghton-Mifflin, New York, NY, 2000, 384 pp., $20.00 paper. The Sibley Guide to Birds, by David Allen Sibley. Knopf, New York, NY, 2000, 544 pp., $35.00 paper. Say goodbye to the basic pocket birding book. Two new guides to North American birds are setting new standards. Kenn Kaufman’s Birds of North America pioneers a novel technique—the use of digitally enhanced photographs. Debates in birding circles have long raged over the merits of paintings versus photos in field guides, so Kaufman tries to provide the best of both with modern computer technology. He alters high-quality photos to emphasize field marks, making each bird’s appearance more typically representative of the species while retaining a lifelike realism. For the most part, he succeeds. The pictures are substantially more helpful for identification than those in traditional photo-based guides. However, photographs capture only one posture under one set of lighting conditions, while illustrations can better represent the essence of a species’ appearance. Kaufman keeps the text simple, color-codes major bird groups, and categorizes birds partly by similarity rather than the traditional scheme of scientific classification. Thus the unrelated bobolink, dickcissel, meadowlark, and lark bunting are grouped together as “Birds of Open Fields”; swifts and swallows are adjacent due to similar flight styles; and Kaufman’s amusing catch-all, “Miscellaneous Micro-Birds,” includes tiny species from three different families. This doctored order may benefit the beginner, but will likely give experienced birders fits as they flip through the index searching for out-of-place species. However, the geographic range maps alone are worth the cover price. An eight-color scheme shows where each bird summers, winters, lives year-round, migrates, and whether it is common or uncommon in the area. For the beginning birder or all-around naturalist, Kaufman’s book provides clear and easy ways to identify and learn about birds. For the advanced birder, it’s a handy field reference and useful complement to other guides. Those advanced birders will surely want to turn to The Sibley Guide to Birds, the most comprehensive field guide to North American birds ever published. Sibley captures details of plumage, voice, and behavior in ways that reveal a deep knowledge of birds. He supplements detailed illustrations with treatments of special subjects, such as how to identify gnatcatchers by tail pattern and hummingbirds by flight display. And his diagrams of the different feather groups, including song, shore, and seabirds, are masterful. Viewing these diagrams and notes, one realizes what has been missing all these years from other guidebooks. Sibley also emphasizes the identification of birds in flight. Every species is shown flying, often with notes on flight behavior. Some of his drawings, however, lack life because of their small size, and the rufous tones run far too orange. Sibley includes many subspecies, but labels them with common rather than the more recognized Latin names employed in other sources. The maps, like Kaufman’s, are superior to those found in other guides; they include locations where birds have occurred as vagrants, suggesting how likely or unlikely it is to find them in areas outside of their normal range. With such depth, Sibley’s book sets a new standard for guides aimed at the active birder. Armed with the new Sibley and Kaufman books, 2001 should be a great year for birding.
Recommended Reading from the Editors’ Desks Bears of the World, by Lance Craighead. Voyageur Press, Stillwater, MN, 2000, 132 pp., $29.95, hardcover. Polar bears can smell the breath of a surfacing seal from several miles away. Sloth bears have evolved large, mobile lips and long tongues to capture ants and termites, their main food source. Combining interesting tidbits like these with striking photography, Lance Craighead takes readers on a guided tour of the world’s bears—the American black, Asiatic black, brown, polar, sloth, sun, spectacled, and the giant panda. But Craighead delves deeper into bear habitat and covers everything from evolution to conservation, providing a succinct but well-rounded snapshot of these awesome and fear-inspiring creatures. Though his discussions of bear evolution can be repetitive, Craighead portrays well the tight-knit relationships of species and the intricate balance of nature. For example, brown bears in the Rocky Mountains, facing a shortage of salmon, now rely on protein-rich moths that migrate there after hatching from agricultural fields in the Great Plains. The result is a beautiful coffee-table book that goes well beyond pretty pictures and pleasing anecdotes. A Living Bay: The Underwater World of Monterey Bay, by Lovell and Libby Langstroth. University of California Press, Berkeley, CA, 2000, 315 pp., $60 cloth, $29.95 paper. The driving force behind this marine tour of Monterey Bay lies in Lovell and Libby Langstroth’s astonishing collection of underwater images. Veteran scuba divers, the authors taught themselves the art of closeup photography to document the tiny universe clinging to the kelp and tidepool crannies along this curve of the California coast. The book is organized by habitat, describing the salient features of illustrated organisms with an emphasis on life cycles and connections with human biology. Though it suffers from uneven writing that explains basic concepts in one paragraph but requires a strong background in biology to understand the next, the book is a beautiful and informative addition to any marine maven’s library. The Oceans, by Ellen Prager, with Sylvia Earle. McGraw-Hill, New York, NY, 2000, 315 pp., $24.95 cloth. Recent oceanographic research that predicted the last El Niño has galvanized the conservation community to renew its arguments for ocean preservation. Ellen Prager and Sylvia Earle argue that we need a sea change to convince the public we need a sea tax to enforce a sea ethic and allow for the exploration and protection of the almost pitch-black wilderness below. Prager, Assistant Dean of the Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, has written wonderful chapters on geography, the restless sea, ocean changes, and marine life. Earle is renowned for her deep-sea explorations and strong advocacy of marine conservation. The work is an easily read introduction to oceanography. And it reminds us that we are not listening closely enough to the song of the endangered seas. |
Spring 2001
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