Friday, March 9, 2007

San Luis Sandhills

The Rocky Mountain sandhill cranes winter in New Mexico. Come February, they begin to migrate toward their summer range in Wyoming, Montana and Idaho. Their one and only stop will the the San Luis Valley of southern Colorado, a high basin surrounded by majestic peaks of the San Juan, La Garita and Sangre de Cristo Ranges. The cranes are attracted to this valley by its shallow wetlands, crop fields, mudflats and wet meadows; though the San Luis Valley sits at 7600 feet and receives only seven inches of precipitation each year, abundant ground water is supplied by streams and subsurface flow from the adjacent mountains.

More than 20,000 sandhill cranes arrive in the Valley by late February and usually find enough worms, tubers, insects and waste grain to keep them around until mid April; their numbers generally peak in mid March. One of the better places to observe these migrants is the Monte Vista National Wildlife Refuge, six miles south of Monte Vista, Colorado. The refuge is accessed by an auto tour road and refuge naturalists will direct you to some of the better viewing areas. In addition to the cranes, March visitors should see bald eagles, short-eared owls, golden eagles, mountain bluebirds and an excellent variety of waterfowl. Mammals include coyotes, mule deer and wintering elk.

In 1975, conservationists began using the Rocky Mountain sandhills as "foster parents" for whooping cranes, attempting to establish a second wild flock in North America. While they managed to imbed 33 whoopers by 1985, the birds never reproduced in the wild and their numbers dwindled to a dozen by 1992. Collision with powerlines, predation, starvation and disease all took a toll.