CAPTURING COMMON RAVENS AND TRACKING BREEDING-SEASON MOVEMENT PATTERNS

Charles G Meyer; U.S. Geological Survey; cmeyer@usgs.gov; Peter S. Coates, Steven R. Mathews

The common raven (Corvus corax; raven) is an intelligent generalist avian predator with a high degree of behavioral flexibility, allowing for populations to exploit anthropogenic resources for breeding substrates and forage. In the American West, raven populations have increased substantially in recent decades, especially in sagebrush ecosystems where they are an important nest predator of greater sage-grouse (Centrocercus urophasianus; sage-grouse). Predation by over-abundant ravens on sage-grouse nests is thought to be a primary contributor to local sage-grouse population declines, particularly across the southwest portion of sage-grouse range. Our study objective was to capture territorial breeding ravens from their nests and fit them with GPS units to identify foraging patterns and relate to sage-grouse nesting areas within sage-grouse nesting periods. Here, we present 1) methodological descriptions of raven captures after testing multiple techniques, 2) preliminary estimates of home range sizes across different life stages, and 3) preliminary movement patterns of ravens during nesting and fledgling stages in relation to sage-grouse nesting habitat. These initial results could help inform management decisions aimed at minimizing adverse effects of nest predation by ravens on sage-grouse populations. These findings are preliminary, subject to change, and provided for best timely science.

Poster Session