Like moon shots, animal migrations inspire a sense of the epic. Caribou herds hundreds of miles long, millions of monarch butterflies flying across North America each fall, Arctic terns migrating from pole to pole -- all these make us stand in awe of nature and the single-minded determination of its creatures. The tiny blackpoll warbler flies 9,000 miles on its seasonal passage; for its size, this is equivalent to 10 moon trips.
"The Mystery of Migration," an impressive tribute to these epic journeys, catches their primeval poetry. The book is beautifully illustrated, with superbly clear and stunning photos, many in color.
But the thrust of the book is less beauty than science. Its authors are a team of British zoologists led by Dr. Robin Baker, whose work on a possible "sixth," or gravitational, sense in humans has been featured on the "Nova" series on PBS television. Like the shows, the book is meant for a general audience, without jargon or inaccessible material.
Yet the book also pursues its subject with rigor, careful argument, and impressive documentation. It's unusual: not simply a big, beautiful nature book , but one that argues out several relatively new theories as well. A model of both technical and popular scientific writing, "The Mystery of Migration" belongs more in the study than on the coffee table.
One new theory redefines migration more broadly than we might think of it. The authors note that Salmon swim thousands of miles in a "return migration cycle" to their birthplace to spawn and die; yet monarch butterflies rarely return to an exact area, and they spawn in the middle of their migration route. Distance, moreover, is relative; minute zooplankton travel as far as salmon just by floating up and down through several fathoms in coastal seas. The authors argue that there is no single model or set standard for migration, and therefore "the study of migration must embrace all movements from birth to death." The sum of these movements they call the "lifetime track."