Ringing high above the West Texas plains, the sound is as bracing as a winter morning, as sharp and clear as a November sky.
The sound of the sandhill crane is winter's calling card for many in West Texas. Tens of thousands of the birds winter on the Llano Estacado, and parts of the Trans-Pecos, each year. The cranes have been making the annual journey to this region for hundreds of thousands of years.
Sandhill cranes typically arrive in West Texas between mid-October and early November – announcing their presence from high above.
Michael Nickell, museum scientist and naturalist at the Sibley Nature Center in Midland, said he anticipates the cranes' clattering song each year.
“They're very high flying birds, and often times I will hear them before I see them,” Nickell said. “Sometimes they fly so high, and with the color of their plumage, they basically disappear in the blue sky. You don't see them, but you can hear them. And so, to me personally, that is probably the iconic sound of fall and the coming winter here on the Llano Estacado – the sandhill cranes.”
Sandhill cranes stand 3 to 4 feet tall, and have wingspans of up to 7 and a half feet. Their plumage is gray, and their foreheads are crowned with streaks of red.
The birds are notable for their stature and their distinctive, rolling cries. But the cranes are just as impressive for the journey they make.
The birds that winter in West Texas have often traveled 3,000 miles or more, from nesting grounds in Alaska and Canada. Some have come from as far away as Asia. Among the birds that winter in the Southwest, 50,000 spend their summers in Siberia.
The cranes travel at great elevations – of up to 12,000 feet – in V formations. They can cover 500 miles a day.
A century ago, sandhill cranes were near extinction – as a result of over-hunting and habitat destruction. But efforts to preserve the bird have been successful, and sandhill cranes are now one of the most abundant crane species in the world. The population is estimated at more than 650,000.
The cranes are drawn to the Llano Estacado because of its playa lakes. The playas are formed when rainfall fills shallow depressions on the plateau. Thousands of these ephemeral lakes dot the Llano Estacado. When rains come, the playas become sites of rich biodiversity.
“Whenever it does rain, there's life and there's life abundant,” Nickell said. “There are tremendous numbers, in the freshwater playas, of amphibians – frogs and toads and salamanders – all good sources of food for migrating birds.”
Salinity varies among the playas. In the lake beds of salt playas, the eggs or cysts of tiny shrimp can lie dormant for years. When playas fill, the shrimp proliferate – providing another food source for migratory birds.
“Fairy shrimp, brine shrimp, tadpole shrimp – we can see some of these in tremendous numbers in our salt playas,” Nickell said, “to the exclusion of just about everything else.”
In addition to the aquatic life of the playas, cranes feed on rodents and insects. For West Texas farmers, the birds can be nuisance. The cranes dine on alfalfa, wheat, sorghum and other grains.
But the playas continue to provide a crucial role for the cranes. When darkness arrives, the cranes retreat to the water.
“They mostly use the salt playas as roosting places at night, to keep them safe from predators like coyotes and bobcats,” Nickell said.
Thousands of cranes can roost in a single playa or salt lake. Large numbers can be seen at Muleshoe National Wildlife Refuge, and at the salt lakes west of the Guadalupe Mountains. To watch the birds gather at dusk – or take flight at dawn – is an awesome sight.
Cranes are among the most ancient of the world's birds. Their lineage extends back into the Eocene epoch, 35 million years ago. A crane fossil found in Nebraska, identical in structure to the modern sandhill crane, is estimated to be 10 million years old.
As markers of seasonal change, cranes have been part of myth and legend around the world. Sandhill cranes feature in the creation stories of native peoples in Alaska.
Hearing the cranes' wild clamor overhead, West Texans are linked to the continent's ancient rhythms.