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Sandhill Crane Migration

Written by Bill Kendall

This is the time of year when the migratory bird species which departed Interior Alaska last Fall return. We celebrate the reappearance of robins calling each other as they seek out the twigs and grasses which they will form into a mud-reinforced nest placed in one of the backyard birches. As much as I welcome the return of the ubiquitous robins, it is a more exotic species that I’m hoping to see: the Sandhill Crane.

Presently I live on a hill which happens to be the high point along the Parks Highway between Fairbanks and Nenana. Because the Sandhill Cranes use this hill as a visual navigation and during clear weather I am situated under a “flyaway,” an aerial migration trail, even though the top of this feature in the landscape is a mere 400 meters above sea-level. In an overcast sky the cranes can make use of the sun as a visual navigational aid so long as they can discern it as the bright spot obscured by clouds. When thick soup makes visual navigation impossible the Sandhills have a fail-safe internal navigation system aboard: the mineral magnetite (non-oxide) functions as their magnetic compass.

Usually I hear the migrating cranes before I see them even if I’m indoors and they are flying, give or take, 500 meters above my roof. Some describe their call as a bugeling sound which carries long distances. You could also describe their calling as similar to the racket which ensues when a stranger walks past a musher’s dog lot while the owner is absent.

One Spring evening I had just set off on a bike ride south-bound on the Parks Highway when I heard the sound of barking high overhead. I pulled off onto the apron of a defunct logging spur road and looked up. It was a flock of cranes, well over fifty but less than a hundred, milling around in a circular fashion. I began counting by tens as additional flights added themselves to this aerial circle dance: sixteen, twenty-seven, twenty-one—- until they had coalesced into much larger flock which came to an estimated 238. In short order a leader emerged and, with everyone accounted for, set a course, roughly north, toward the Minto Flats, presumably for an overnight camping place.

The Minto Flats consist of what one could call ideal habitat for cranes, a huge expanse of true wetlands. These they would find all manner of ponds, pothole lakes, lakes large enough for landing a floatplane, the lower Chatanika River where it meanders slowly as if it had gotten lost plus an endless supply of sticks and grasses to pile up into mounds to nest upon and the fresh shoots, insects and fresh water mollusks they require as food.

Once, while berry picking along a stretch of the Elliott Highway where it makes a sort of line of demarcation between the Minto Flats and the White Mountains, I discovered the location of a Sandhill Crane nest without actually getting to see the mound or the birds on it. It would have been easy enough to step from tussock to tussock until I had everything in full view. I settled for listening to some avian conversation before slipping away, lest I frighten them into taking flight. Later that Summer, on a gloomy, overcast August afternoon I spotted the two adults flying across the highway on the way back to their nest and then the two juveniles following close behind. That was a sufficient thrill – the joy of knowing everyone had made it.

Sandhill Cranes are large birds with wingspans reaching 2.3 meters, comparable in size to eagles and swans, for example. Adult weights range from 3.5 to 5 kilograms. Adult plumage is mostly gray, with black wingtip, a red patch atop their heads and a white check patch behind their black beaks. There is a good reason for this species to be slightly secretive about their nest location; only one or two eggs, greenish are produced per year. (This figures in the slow recovery of the Whooping Crane population which dwindled to near extinction in the mid-twentieth century).

A good place to view cranes during migration is at Creamers Field where spotting scopes are located along the fence near the parking area, the U.A.F. Experimental Farm fields near Geist Rd. and the Parks Hwy and sometimes private farm fields. Between Spring and Fall migrations it is much more difficult to spot cranes because they spend most of their time in close proximity to their nests until the juveniles are close to being able to join the Fall migration.

 

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Bill Kendall

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