DISTRIBUTION AND STATUS OF GREATER SANDHILL CRANES IN NEVADA

Nesting habitat of the Lower Colorado River Valley Population (LCRVP) of greater sandhill cranes (Grus canadensis tabida) was censused in northeastern Nevada from 1983 through 1986. Ninety-two nesting pairs and 594 cranes were located. Eighty-two percent were observed in central Elko County. Cranes were marked from 2 summer range locations and from the Lund, Nevada traditional spring migration stopover with patagial streamers. Cranes marked on summer range wintered on the lower Colorado River, in the Imperial Valley near Brawley, California and on the Gila River in southwestern Arizona. Cranes marked at the stopover were observed on summer range in Elko County and lower Colorado River winter range. Two cranes marked at the stopover were also observed on Rocky Mountain Population (RMP) fall staging and wintering areas indicating a portion of cranes using the stopover are members of the RMP. Spring stopover counts are not a valid measure of LCRVP trend because an unknown number of cranes from at least 1 other population also use the stopover, peak periods of use vary from year to year and peak numbers using the stopover can fluctuate drastically between years. The only method currently used to monitor the size and trend of the entire LCRVP are censuses cond ucted on winter range. The LCRVP probably numbers between 1800 and 2000 birds. If significant numbers of cranes from adjacent populations also winter with the LCRVP, winter range counts would be rendered invalid