Last Friday morning, as a cold sun struggled to rise above the eastern wall of the San Luis Valley – the 125-mile-long, 7,000-foot-high, Oklahoma-flat basin that lies between the San Juans and the Sange de Cristos in southern Colorado – a throng of birdwatchers climbed aboard a yellow school bus to observe one of the greatest migrations in the West.
The occasion was the arrival of sandhill cranes, majestic gray birds graced with red-feathered facemasks and six-foot wingspans. Around 20,000 sandhills pass through the San Luis Valley every year on their way from wintering grounds in New Mexico to summer homes in Idaho and Yellowstone. While that population pales in comparison to the half-million cranes that annually flock to Nebraska’s Platte River, 20,000 giant birds are nothing to sneeze at – especially in a world losing its migrations to habitat destruction and fragmentation.
Every year, the sandhills’ return catalyze another movement of biomass: Thousands of humans, from as far as Japan and Australia, congregate in the town of Monte Vista (population: 4,400) for the Monte Vista Crane Festival. Perhaps because it was the festival’s first day, no one on the bus last Friday was from Japan – the most exotic place of origin was Boulder. Still, these were craning veterans; war stories of migrations come and gone trickled up the aisle. Refuge manager Suzanne Beauchaine, blond curls popping from beneath a brown baseball hat, spoke into a microphone at the front of the bus. “They showed up three weeks ago en masse,” she said as we hung a wide left at Dairy Queen and headed for the Monte Vista National Wildlife Refuge. “Maybe it was the mild winter, but it’s been great so far this spring.” An excited shiver went through the bus.
At the refuge, the first stop was a large rectangular wetland where cattails glowed gold with the waxing dawn. Mallards cruised the pond; American coots plunged beneath the surface like fishing bobbers. A quartet of buffleheads, small ducks en route to Alaska and Canada, skittered along the water in surprised flight. Beauchaine scanned the bucolic scene. “This will be chockfull of nesting yellow-headed blackbirds,” she said.
There was a long, serene silence. “Where are the cranes?” someone called from the back. The bus grumbled obediently back into motion.
Five minutes down the road, there they were, perhaps a hundred elegant sandhills, curved necks dipping like pumpjacks as they browsed a dun-colored grainfield. We stood behind a wooden fence, binocs lifted, cameras clicking. The U.S. Fish and Wildlife Service, Beauchaine explained, allows a local farmer to plant alfalfa on this land for free, provided he grows an equal amount of barley for the cranes to carbo-load. While other farmers harvest barley in the fall, FWS lets it stand until spring, then mows the grains to the ground once the birds show up.
“They’re actually kind of lazy,” Beauchine laughed. “They won’t eat the seed off the head.”
While two centuries of agriculture have spelled disaster for many western wildlife species, sandhill cranes are among its primary beneficiaries. Migrating cranes have two major needs, says Mike Blenden, project leader for the San Luis Valley’s refuges: a food source and a wet roost. (Cranes sleep with their feet in shallow water in order to hear predators approaching.) In the valley, agriculture provides both the food, in the form of grain, and the roost, in the form of artificial wetlands. The San Luis is a high-elevation desert that gets only 7 inches of precipitation per year, and while the San Juan Mountains provide runoff into the valley, farmers have created lots of additional wetland habitat by pumping up groundwater and diverting surface water to irrigate pastures. “We frankly don’t know how many cranes were here 200 years ago (before agriculture),” Blenden says. “Was it 20, or 20,000?”
When the federal government created the Monte Vista Wildlife Refuge from private farmland in 1952, refuge managers kept on pumping and channeling water into 7,500 acres of wetlands (compared to just 1,000 acres that existed pre-ag). And when Colorado mandated that the irrigation season not begin until April 1, the refuge finagled a dispensation allowing them to provide water year-round so that wetlands would be open for the March migration.
Yet with the San Luis Valley suffering through a decade-long drought – or perhaps coming to grips with a new normal – those artificial wetlands, which the refuge fills with 2.67 billion gallons of groundwater, could eventually be in jeopardy. Stop me if you’ve heard this one before, but snowpack and groundwater are on the wane, while consumption levels still don’t reflect the arid reality. “People who’ve been around Monte Vista all their lives can’t believe how dry it is now,” Blenden says. “The trendlines are not comforting.”
The community-based groundwater management system that now governs parts of the valley – an innovative, ambitious approach to water conservation whose collaborative design has earned the region the nickname “Kumbaya Basin” – could eventually prove the San Luis Valley’s salvation. In the nearer-term future, however, the new scheme may make life harder for the refuge, which has to find water (perhaps through the acquisition of new surface rights) to replace the groundwater it pumps, or risk paying fees of over $1 million. “We’re part of the system, and we’re also part of the problem,” says Blenden. “This isn’t an agriculture versus wildlife controversy – this is about how we all have to collectively bring groundwater back into a sustainable situation.”
Regardless, letting crane habitat go dry, Blenden told the Denver Post last week, is not a “realistic outcome.”
Back on the bus, returning from the crane field into town, the bearded man behind me raised his hand. “You know how a flock of geese is called a gaggle?” he asked. “What’s a group of cranes called?”
Beauchaine was stumped. “I’m going to have to cheat on this one,” she said. She took out her iPhone and ran her finger across the screen. “A group of cranes is called a herd, a siege, or a sedge,” she read. “A sedge of cranes. I like that.”
Out the window, black rivers of birds flowed through the heavy sky, voices blaring like trumpets. Siege seemed more apt – a beautiful, cacophonous siege in need of food and water like any army, now dependent on humans for provisions.
Ben Goldfarb is an editorial intern at High Country News. He tweets @bengoldfarb13.