Two hundred pages on a single insect might strike some readers as overkill, but the monarch butterfly deserves every one.
As fall temperatures drop, monarch butterflies throughout the Eastern US and Canada migrate south of the Rio Grande. No one knows how they make this journey of several thousand miles (memory cannot guide them, since three or four butterfly generations pass in a year). No one even knew where they spent the winter until the 1970s, when researchers discovered that millions of migrating monarchs collect regularly in a few small patches of forest in the remote Neovolcanic mountains of Mexico, where they cover every visible surface and fill the air with the sound of their wings. This phenomenon has fascinated laymen as well as scientists. Halpern (Migrations to Solitude, not reviewed) was captivated after visiting a butterfly reserve during a Mexican vacation, and she manages to convey her enthusiasm to the reader. Rather than research the subject herself, she finds the experts and lets them tell the story. She drives a battered pickup to remote mountains (with a grizzled field biologist who has spent his life studying the monarch), visits universities where precise chemical analyses are teasing out the insect’s secrets, and reports on the work of the amateurs (an often eccentric but dedicated group who are making important contributions—they have, for example, tagged tens of thousands of butterflies, many later recovered far across the continent). Inevitably, the author writes about the future (almost always a depressing subject when wildlife is involved) and points out that the monarch is not endangered, even if logging operations are steadily reducing its wintering habitat in Mexico.
An appealing account.