ALAMOSA, Colo.—Quiet, except for the squawking. Vacant, except for thousands of squawking birds and the occasional gawking motorist. And blissful, except for the birds whose day-to-day busyness keeps them squawking. That pretty much sums up life at the San Luis Valley wildlife refuges for the next few weeks. After that, the sandhill cranes—the loudest and most charismatic of the squawkers—and other birds will head south for the winter.
“My guess is that by mid-November, if not a little bit sooner, the cranes are going to be gone,” said Scott Miller, refuge biologist at the San Luis Valley National Wildlife Refuge Complex.
The complex is a trio of national wildlife refuges—Monte Vista, Alamosa and Baca—managed by the U.S. Fish and Wildlife Service. The 14,804-acre Monte Vista refuge was the first of the refuges, created by the Migratory Bird Conservation Commission in 1952. The 11,169-acre Alamosa refuge followed a decade later, the 78,697-acre Baca refuge in 2000.
Having emerged recently from years of litigation over a gas-exploration proposal, the Baca refuge, located near Great Sand Dunes National Monument, remains closed to public access. Project leader Michael Blenden, who oversees the operation of all three national wildlife refuges, said a planning process is under way to reopen the refuge.
“It’ll be closed to public access until we go through a public process to open it. And that’s what we’ll be doing starting this November.”
The complex provides haven for migratory birds, songbirds, raptors, water birds and other wildlife like mule deer, coyotes, rabbits and beaver. Canada geese and ducks, especially mallards, are bountiful at the refuges. About 40 percent of Monte Vista and Alamosa refuges are open to waterfowl hunting in the fall, said Blenden, but this takes place apart from prime viewing opportunities.
Miller said the ducks and geese depart when temperatures consistently dip below freezing.
Colonial waterbirds, such as the white-faced ibis, snowy egrets and black-crowned night herons, are already gone, he said, but sandhill cranes remain in abundance.
Vocal birds, a spree of squeaky-wheel yawps from a congregation of excited sandhill cranes is unforgettable. In the fall, sandhill cranes use the San Luis Valley as a major stopover point on their migration from their breeding grounds in the greater Yellowstone area. From the valley, cranes fly to wintering grounds in New Mexico.
“Right now, we have about the peak numbers that we’ll have in the fall,” Miller said. “We’d estimate about 18,000 to 20,000.”
He said all cranes visible now are greater sandhill cranes, the largest of three migrating subspecies of sandhill crane—greater, Canadian and lesser.
With grayish plumage and a red forehead, they can reach 5 feet tall and weigh 14 pounds.
In the spring, the number of cranes jumps to 26,000 because both greater and lesser sandhill cranes pass through.
Lesser sandhill cranes can reach 3-1/2 feet tall as adults and weigh up to 7 pounds.
Weather and food determine when the greater sandhill cranes fly to wintering grounds in New Mexico’s Rio Grande Valley and the Bosque del Apache National Wildlife Refuge near Socorro.
Roosting areas in the wetlands have remained unfrozen, which is a determining factor in whether cranes stay or go.
“Cranes will stand in the water during the night, primarily to avoid predators,” Miller said.
He said that in the fall, the refuge floods the wetlands with water from artesian wells to maintain roosting habitat, much of which is within view of either side of Colorado Highway 15 from auto pullouts just a half-mile south of the Monte Vista refuge’s visitor center.
“Our auto pull-offs down there are probably the best opportunities to really see them,” Miller said, adding that the best times for viewing are early morning or just before dusk.
After sunrise, cranes fly to wetlands and farm fields to feed.
Miller said they eat insects, spiders, mice, frogs, barley, grass seed—whatever.
“They’ll eat everything. Cranes are pretty much the ultimate omnivore,” he said.
When roosting areas freeze over, the cranes move out. Within months of the cranes’ departure, the next winged celebrity arrives. Bald eagles will take up residence in the wetlands of the Alamosa refuge.
The draw there, explained Blenden, is a banquet of dead fish, primarily carp, which bald eagles and other raptors find flash-frozen in pools left over from irrigation.
When the pools thaw slightly, the birds feast.
“They’ll be down here around Christmastime or so,” said Miller.
Around the second week of January, wildlife officials drive almost every road in the valley counting eagles.
“The last number of years, it’s averaged about 100, give or take,—100 or 120 eagles,” Miller said.
The best place to view them in January and February is at the Alamosa refuge along the Rio Grande River, if the river isn’t frozen over.
And when the bald eagles disperse in March, the crane migration starts anew.
