Dawn’s early light slides over Nebraska’s wide Platte River, revealing what appear to be dusky gray islands. But as the March morning’s candlepower increases, one sees that the islands are moving. They are birds. Tens of thousands of them, standing knee-deep in the current, stretching their wings, prancing in place, throwing their beaks to the sky.
Each spring, from mid-February to mid-April, more than 600,000 of the gangly but elegant birds descend upon the Central Platte Valley. Representing about 80 percent of the North American crane population, they have come from Mexico, Arizona, New Mexico and Texas on their way to northern Canada, even Siberia, to nest.
The cranes have gathered here for eons on their migration to feed and socialize.
“The cranes stop here, we believe, because of the habitat,” says Keanna Leonard, education director at Audubon’s Rowe Sanctuary on the banks of the Platte near Kearney, Neb. “They use the shallow Platte River to sleep in. They stand in the shallow water, and there’s plenty of food for them.”
The food is primarily waste corn left in the rich farmland along the river, but in nearby wet meadows the cranes also will eat snails, frogs and snakes. They’ll turn over cowpies to pluck tasty insects or their eggs.
The cranes will put on an additional 18 to 20 percent of body weight during their stopover, critical stores for the coming nesting season.
The migrating birds roost in the river for safety. Standing in mid-river, the cranes can hear the splashing of any coyote or fox trying to steal a meal.
Big bird, big draw
The gathering of cranes is a spectacle to behold, and thousands of people are drawn to the river each spring to witness the phenomenon. Rowe Sanctuary draws about 20,000 visitors each spring from all 50 states and, last year, from 66 foreign countries. Some 6,000 of them make morning or evening visits to the sanctuary’s blinds along the river.
That’s where about 20 of us are gathered on this cool morning, along with two volunteer guides from Rowe Sanctuary. The cranes, 3 to 4 feet tall with 6-foot wingspans, are greeting the new day. They dance in place, doing intermittent hop-flaps that are thought to be part mating ritual, part tension relief, part pure exuberance.
Triggered by some cue unknown to humans, the cranes begin to lift off in gaggles of five, 20, 50 or more until at times the sky is darkened with their numbers. Before and during take-off, the morning air is saturated with their shrill and resonant calling. Their vocalizations, as wild and ancient-sounding as the calling of loons, is a guttural trill, a raspy rattle, not quite a tom turkey gobble, a truncated yodel. If you are close enough, you can distinguish the calls of practicing juveniles from adult males and adult females — a wild combination of terrier barks, yaps and squawks.
Their calls can be heard for at least a mile, and sometimes they seem to have a ventriloquism quality. You’ll hear a call and look up, expecting to see a crane directly overhead. But no crane is there. You scan the sky and perhaps eventually track down the source a cornfield away. Or maybe you never locate the bird at all.
Rob Ahlschwede, a 13-year volunteer at Rowe Sanctuary from Olympia, Wash., said the crane count during our recent visit was about 118,000. It peaked at more than 400,000 in mid-March.
Against the odds
Like many species of wildlife, these sandhill cranes have been affected by humans. The cranes compete for water in the Platte River, described by early settlers as “a mile wide and an inch deep.” It isn’t the Platte it once was. After originating in the mountains, 90 percent of its flow is siphoned off for irrigation, drinking water or urban development, according to the Audubon Society.
Spring floods once scoured the river’s sandbars clear of vegetation, but with reduced flows, that no longer happens. Brush and trees have taken hold on many of the sandbars, but those in the areas managed for cranes are machine-cleared so the birds will have places to roost.
The cranes remain in the fields each day until sunset or after. Travelers along I-80 in Nebraska are accustomed to seeing long lines of the big birds flying overhead or feeding in last fall’s picked corn fields between Grand Island and Kearney. As dusk gathers, the cranes begin streaming back to the river in a flight that lasts for at least an hour and a half.
At first, they come in small groups, but as dusk settles in, they assemble in huge waves. Their calling fills the sky. As daylight fades, the waves fly lower and lower, until it seems one could reach up and touch them. Four or five birds from a flight of hundreds might drop out and land lightly on a sand bar. Then hundreds or thousands pile in around them.
“You think there’s no more room on the sand bar, and they keep coming in,” said Rowe Sanctuary volunteer John Wupper of Blair, Neb.
They keep chattering after they’ve landed until the entire river is alive with movement and calling. Darkness envelops the landscape, and still more cranes come. Visitors pause on their way back from the Rowe Sanctuary blinds, gazing skyward at the dark forms of cranes flowing past Orion in the southwestern sky.