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San Luis Valley Sandhill Crane Migration

By Jared Coburn

"A Miocene crane fossil, thought to be about ten million years old, was found in Nebraska and is structurally identical to the modern Sandhill crane, making it the oldest known bird species still surviving!"

- savingcranes.org

Cranefest

Each spring, the population of Monte Vista nearly doubles as enthusiastic birders gather to celebrate the Sandhill crane migration. The Cranefest festival features lectures, guided refuge tours, films, a craft fair, workshops and meals. Most activities are free and open to the public; tours are by donation and meal prices are quite reasonable. A detailed schedule, registration forms and lodging information can be found at www.cranefest.com. Lodging reservations should be made far in advance.

Alamosa/Monte Vista National Wildlife Refuge

March - November, Monday - Friday, 10 a.m. - 4 p.m.(719) 589-4021; www.fws.gov/alamosa

The Monte Vista National Wildlife Refuge is located 6 miles south of Monte Vista on Colorado Hwy. 15.")

For the last hundred centuries or so, the San Luis Valley has borne witness to Colorado's most spectacular annual ornithological event - the spring Sandhill crane migration. Standing close to four feet tall, these enormous birds sport six-foot wingspans, and they gather each spring by the thousands.

The migration begins in mid-February when a trickle of Sandhills arrive from its winter grounds around Bosque del Apache National Wildlife Refuge near Socorro, N.M. In the following weeks, the birds continue to pour into the valley until by mid-March, the peak of migration, the Monte Vista National Wildlife Refuge is bursting with close to 25,000 of these magnificent birds.

It is a density that must be seen to be believed. It is breathtaking. Morning and evening, on their way to and from their feeding grounds, the cranes crowd vast fields with their gray forms. The cranes travel in small groups of several dozen. When the birds are on the move, it is a pleasure to witness flight after flight passing overhead while distant flocks dot the sky from horizon to horizon.

Sandhills are noisy birds, and the sound of several thousand of them in close proximity borders on deafening. It is a bizarre croaking vocalization that sounds far more reptilian than avian. For a bird that is said to have populated this planet for the past 40 million or 50 million years, it is a sound entirely suggestive of the Sandhills' prehistoric origins.

These are the birds of the Rocky Mountain Sandhill population. Their migratory pattern resembles an hour glass; the neck of which is centered squarely in the heart of the San Luis Valley. And it is here they pause for a few weeks each spring before the journey to their northern breeding grounds. They spend their days loafing in wet meadows, fattening up on waste grain in surrounding agricultural fields, and most spectacularly, dancing for their mates.

The Rocky Mountain population comprises three sub-species of Sandhill: Greater, Lesser and Canadian. But the differences between them are subtle. The Greater Sandhills are the larger birds and make up the vast majority of the cranes in the valley. The Lesser and Canadian Sandhills, slightly smaller, number only in the several thousands each. East of the Continental Divide, another Sandhill population pauses for a few weeks along Nebraska's Platte River. This Central Flyway population is dominated by Lessers rather than Greaters and gathers to the tune of a quarter-million birds.

Beyond the wonder and amazement at the sheer number of birds, it is the dancing that delights viewers young and old. Their courtship display involves an elaborate sequence of bows, head bobs, wing flaps and great leaps into the air. When things get really heated up, the cranes might begin tossing sticks or tuffs of grass into the air. It is an indescribable ritual; probably best described as a dance. While sub-adults and unpaired adults spend their days practicing their moves, perhaps tempting a future mate, mated pairs dance in affirmation of their mutual commitment. Cranes, it should be noted, mate for life. Often the dancing is contagious. A single pair might incite a dozen or more to dance. These are big birds and dozens flapping and leaping in close proximity can appear a little ungainly. But it can't fail to elicit a smile.

Then one morning, on some random date in late March when the thermals are just right, the birds will get up en masse and push north to their summer breeding grounds in the greater Yellowstone region of Wyoming, Idaho and Montana, concentrating around Gray's Lake National Wildlife Refuge near Pocatello, Idaho. The migration works both ways, spring and fall. But the cranes tend to trickle through in the fall. They do not concentrate in the numbers that make the spring migration such a special event.

Jared Coburn is a birding nut, following birds wherever he finds them from either behind a pair of binoculars or his bird dog, Ellie. He lives in Fort Collins, Colo., but makes regular forays to the Southwest to play.