Date of this Version
Littlefield, Carroll D., and John E. Cornely. Nesting success and production of greater sandhill cranes during experimental predator control at Malheur National Wildlife Refuge, Oregon, 1982-83. In: Urbanek RP, Stahlecker DW, eds. 1997. Proceedings of the Seventh North American Crane Workshop, 1996 Jan 10-13, Biloxi, Mississippi. Grand Island, NE: North American Crane Working Group. pp. 62-66.
Greater sancfrtill cranes (Grus canadensis tabida) nest commonly on Malheur National Wildlife Refuge, Oregon, but depredations by common ravens (Corvus corax) and coyotes (Canis latrans) contributed substantially to low recruitment during the 1970's. An experimental predator removal study was initiated in 1982 to determine if nesting success and recruitment would increase if predator populations were reduced. We monitored 120 crane nests located in 2 treatment areas (ravens and coyotes removed, and only ravens removed) and 1 control area (40 nests per area). Nesting success between the 2 predator control areas differed significantly during the 2-year study, but not between either predator control area and the area where no predators were removed. Two years of predator removal did not sufficiently reduce the number of predators in the study area to increase nest success to a level that would maintain a stable nesting population.