If you have an invitation to fly with cranes on their annual spring migration, by all means take them up on it! If not, I highly recommend reading The Birds of Heaven: Travels with Cranes (North Point Press, 2001), by Peter Matthiessen. This book is one of my all-time favorites.

Matthiessen, now 83 years old, is a naturalist, environmental activist, and wilderness traveler, and a prolific writer of fiction and nonfiction. He has won the National Book Award twice. Robert Bateman's beautiful paintings and drawings of cranes guide the reader through the book.

Cranes are the largest flying birds on earth and are considered sacred in many cultures. They migrate long distances, sometimes at great heights.

"That cranes may journey at such altitudes, disappearing from the sight of earthbound mortals, may account for their near-sacred place in the earliest legends of the world as messengers and harbingers of highest heaven," Matthiessen writes.

Since ancient times, cranes have symbolized longevity, good fortune, harmony, and fidelity. Preserving their ecosystems has become an international challenge:

The crane family (Gruidae) occurs on every continent except South America, but the genus Grus (to which taxonomists presently assign all but five of the 15 extant species) attained its greatest expansion in eastern Asia. Of those 15, 11 are threatened or endangered by Homo sapiens, either directly through hunting, poisoning, or trapping, or indirectly through despoliation of the earth's resources, most dangerously its dwindling fount of good freshwater.

In researching The Birds of Heaven, Matthiessen made many journeys in search of cranes—from their breeding grounds in Siberia and Mongolia to India, Bhutan, China, Japan, and Korea; on to Australia, Africa, and Great Britain; then to Wisconsin, Nebraska, and the Gulf Coast and Florida. He often traveled with other "craniacs," including George Archibald and James Harris, officers of the International Crane Foundation in Baraboo, Wis., who wrote the foreword to this book. Although nationalities, politics, and economics create tensions among crane researchers, helping ensure the survival of these beautiful birds and their endangered habitats brings the scientists together in a unified cause.

In a fascinating but ironic part of The Birds of Heaven, Matthiessen describes his trip to a strange "bird sanctuary" in Korea. The armistice that ended the Korean War in 1953 established the demilitarized zone, or DMZ. This stretch of peninsula between North and South Korea, which has been aggressively patrolled by soldiers from both nations and where Homo sapiens is excluded, has been hospitable to other species. This no-man's-land several miles across and 149 miles long has been "the most fiercely protected wildlife sanctuary anywhere on earth, and an accidental paradise for the great cranes."

One of my treasured bird-watching memories is a trip I took in 2001 with my favorite editor and another dear friend to the Lillian Rowe Sanctuary on the Platte River in Nebraska, which is administered by the National Audubon Society, to watch the spring migration of sandhill cranes. This species, which has been estimated at 650,000 birds (more than three times as many as the Eurasian crane and almost as many as all of the other 14 species together) is also the oldest bird species on earth. Matthiessen describes this migration:

In late winter and early spring, all over the Gulf Coast, the Southwest, and northern Mexico, the sandhill cranes grow restless. Calling and circling, they gather up their flocks until at last the cycle of the turning earth propels them on their annual migration. … [T]he skeins of birds funnel like sand grains into the narrow waist of the great hourglass of the continent's central flyway and descend to the great staging area along the Platte River ...

Because farming requires massive irrigation, this crane habitat has shrunk from 200 miles of river to a 60-mile stretch, where crane flocks crowd dangerously together. This loss is a consistent theme throughout The Birds of Heaven:

One way to grasp the main perspectives of environment and biodiversity is to understand the origins and precious nature of a single living form ... [I]f one has truly understood a crane—or a leaf or cloud or a frog—one has understood everything. In the growing scarcity of good water and the impending competition for this resource—which may well become the greatest crisis for all life on earth in the new millennium—the plight of Homo may not differ much from that of Grus.

If we want to preserve the last wild creatures and their habitat, we need to find the will and the means to undo the damage we have created.

Related readings and resources

• Peter Matthiessen, The Snow Leopard (Viking Press, 1978). This National Book Award winner is an account of Matthiessen's two-month journey, after his wife's death from cancer, with naturalist George Schaller in 1973 to Crystal Mountain, in the Dolpo region of the Himalayas, to observe the rare and beautiful snow leopard.
  
• Paul A. Johnsgaard, Crane Music: A Natural History of American Cranes (Lincoln, Neb. University of Nebraska Press, 1998.) Crane Music describes in detail the two North American crane species, the sandhill and the whooping crane, struggling back from near extinction.
  
• The International Crane Foundation, www.savingcranes.org. This foundation works worldwide to preserve cranes and their wetland habitats. It maintains a population of all 15 species for breeding and reintroduction to the wild.