Sandhill Cranes are regularly found during the winter in the Sulphur Springs Valley of southeastern Arizona. The cranes migrate into the valley as early as September and stay as late as March, with the majority of the birds present during the months between November and February. Cranes that spend the winter in the Sulphur Springs Valley represent two populations, the Rocky Mountain and the Mid-Continent populations.

The Rocky Mountain population is made up of the greater subspecies, Grus Canadensis tabida. The nesting range for these birds centers around Grays Lakes National Wildlife Refuge in Idaho with other nesting sites in Wyoming, Montana, Utah, and Alberta. An estimate for this entire population based on a survey conducted in 2004 is approximately 20,000 birds. Winter range for these birds include southwestern New Mexico, mainly the area surrounding Bosque del Apache National Wildlife Refuge, the Sulphur Springs Valley and northern Mexico.

The Mid-Continent population includes three subspecies of Sandhill Crane: the lesser, Grus Canadensis Canadensis; the Canadian, Grus Canadensis rowani; and the greater. The nesting range of this population includes central and northern Canada, Alaska, and northeastern Siberia. This population, estimated to contain approximately 500,000 birds, winters in Oklahoma, Texas, New Mexico, southeastern Arizona, and northern Mexico. The Sulphur Springs Valley usually has around 30,000 cranes each winter. This number is based on an annual survey conducted by the Arizona Game & Fish Department. The 2008 Sandhill Crane count completed in January recorded the highest total ever at more than 36,400 birds.