Sandhill crane colt. (photo: USFWS)

Marti Collins, Ruby Lake NWR
In early June 2008, Ruby Lake National Wildlife Refuge and other select areas in northeast Nevada became the center of a three-year research project on the Lower Colorado River Valley population of the Greater Sandhill Crane (Grus canadensis tabida).  The purposes are to determine crane colt survival rates on their known breeding range; verify factors that affect these rates; and ascertain what changes to previously described summer breeding range, winter range and stopover sites for this population have occurred since the last major marking study. 

This study compliments a simultaneous crane distribution study coordinated by the Arizona Department of Game and Fish that is designed to mark this same population of birds on winter habitat along the lower Colorado River.  Other cooperators include the Nevada Department of Wildlife, the Service’s Division of Migratory Bird Management, Cibola and Sonny Bono National Wildlife Refuges, and other members of the Pacific Flyway Study Committee (from California, Idaho, Utah and Oregon).

This research was initiated, in part, because of the poor crane colt survival documented on Ruby Lake NWR.  A previous investigation determined that 60 percent of the loss of crane colts on the refuge was from coyote predation.  Colt survival on ranches and other agricultural lands in northeast Nevada is thought to be higher because of standard ranching practices.