LINKING MICRO AND MACRO-SCALE HABITAT FACTORS TO VITAL RATES OF DECLINING RING-NECKED PHEASANTS IN THE CENTRAL VALLEY OF CALIFORNIA.
Ian A. Dwight; U.S. Geological Survey; 800 Business Park Drive, Dixon, CA, 95620; (916) 838-0351; idwight@usgs.gov; Peter S. Coates, Jessica H. Vogt, Joseph P. Fleskes, Daniel P. Connelly, Scott C. Gardner
Avian species within agricultural landscapes of California have experienced considerable declines in recent decades. Large-scale changes in farming practices have been reported as major drivers of population dynamics, but effects of habitat conditions at multiple spatial scales on probability of occurrence and demographic rates (e.g., nesting and brood rearing) are not well documented for many species. We evaluated factors influencing demographic rates of ring-necked pheasant (Phasianus colchicus; hereafter, pheasant), a potential biomonitor species, within the Central Valley of California. Specifically, we measured environmental characteristics directly at nest and brood locations in the field, as well as within a Geographic Information System, to characterize large-scale effects relative to radio-marked female pheasant (n = 190) across five study areas during 2013-2017. We used these environmental factors as covariates in models of selection and survival. Our models indicate that management actions focused on promoting increased perennial grass cover at the microsite level and proportion of upland vegetation at larger spatial scales would be most influential toward increasing recruitment rates of pheasant. Evaluating environmental factors influencing selection and fitness can help guide management aimed at increasing productivity of pheasant and native farmland bird species. Findings are preliminary and provided for timely best science.
Ecology and Conservation of Birds I