EFFICACY OF MANIPULATING REPRODUCTION OF COMMON RAVENS TO CONSERVE SENSITIVE PREY SPECIES: THREE CASE STUDIES

Corina A Sanchez; Idaho State University, U.S. Geological Survey; corinasanchez@isu.edu; Brianne E. Brussee, Peter S. Coates, Kerry L. Holcomb, Seth Harju, Timothy Shields, Mercy Vaughn, Brian G. Prochazka, Steven R. Mathews, Steffen Cornell, Chad V. Olson, David J. Delehanty

Predation by subsidized common raven (Corvus corax; raven) populations is linked to population declines of several sensitive species. Ecosystem managers seek strategies for mitigating the adverse effects of raven predation where unsustainable predator-prey conflicts exist. We present three case studies examining how manipulating reproductive success of ravens influences demographic rates of two sensitive prey species. These studies examine impacts of removing raven nests or oiling raven eggs on nest survival of greater sage-grouse (Centrocercus urophasianus; sage-grouse) in Wyoming and the Great Basin as well as survival of juvenile Mojave desert tortoises (Gopherus agassizii; tortoise) in the Mojave Desert using tortoise decoys. Initial trial years from all three studies were consistent in finding improved vital rates associated with the application of strategies for reducing reproductive success of ravens. Raven nest removal resulted in increased nest survival of sage-grouse within treatment areas where predation by ravens was the primary cause of nest failure. Additionally, nest survival of sage-grouse and survival of juvenile tortoise decoys was higher following raven egg-oiling across six treatment areas. These findings inform raven reproduction management practices as important tools for conserving wildlife. Findings are preliminary and provided to meet the need for timely best science.

Raven Management for Conservation Outcomes   Student Paper InPerson Presentation