American Scientist

Chasing Monarchs: Migrating with the Butterflies of Passage. Robert Michael Pyle. 307 pp. Houghton Mifflin, 1999. $24.

Fascinated by butterflies since boyhood, Bob Pyle has long been an active participant in efforts to conserve the monarchs' overwintering grounds in Mexico and California and is well qualified to write about them. His previous publications include natural history guidebooks and essay collections, but this is more of a travel book—with butterflies.

It chronicles a journey inspired by a glaring gap in our knowledge. The migration patterns of eastern North American monarchs are well established (they converge on surprisingly small areas of Mexico), but knowledge of the travel routes of the sparser western monarch populations is largely inferential. Their only known overwintering ground is a section of the California coast, and extremely few specimens tagged outside California have been recovered there.

Pyle's approach to investigating the movements of western monarchs was idiosyncratic, to say the least: With his car "Powdermilk" and his butterfly net "Marsha," he set out to literally follow the insects south, starting at their northernmost western breeding grounds near the Canadian border and taking the direction of each migrating monarch he saw as a cue to determine his own trajectory. Finding the next suitable habitat in that direction, he would search for another butterfly and do it again, "monarch by monarch."

This idea seemed more straightforward in anticipation than it proved to be in practice. Again and again he lost sight of monarchs before they took wing. Roads dead-ended, blocking further progress. Although he had expected the monarchs to lead him to California, he actually took a very different route, through the Great Basin and the American Southwest to the Mexican border. Huge gaps in the chain of butterfly observations prevented Pyle's journey from demonstrating the migration to Mexico of any western monarchs from north of Arizona, but his experiences certainly suggest a direction for further study.

Those expecting a straightforward narrative do not know their author. He is given to philosophizing, and digressions are found on almost every page, ranging from what he was listening to on the radio, to the local history of hamlets he passed through, to an account of chasing his windblown sleeping bag through the night—buck naked. The storytelling mode is vintage Pyle. Verbal flights of fancy range from the poetic to the occasionally jarring. In such a wide-ranging book, a few bloopers are perhaps inevitable—parasitic wasps don't dig burrows, nor do spiders give live birth—but these are minor.

Telling tales of the wonders encountered on a journey through strange lands is a book strategy that dates back to Homer but still has the power to fascinate. Some readers may be put off by the discursive style, but those who have enjoyed Pyle's previous books won't be disappointed.—Rod Crawford, Burke Museum, University of Washington, Seattle