Abstract
Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus) have experienced range-wide population declines, primarily as a result of habitat loss or degradation, and currently occupy <10% of their historical range. Expansion of wind-energy development across the current, occupied Columbian sharp-tailed grouse range is a potential threat to the subspecies. To assess the potential effects of wind-energy development on vital rates of Columbian sharp-tailed grouse offspring, we monitored 68 broods of radio-marked females captured at 11 leks in restored grasslands within 14 km of a 215-turbine wind-energy development complex in eastern Idaho, USA from 2014–2015. We assessed the influence of wind turbine density, habitat characteristics, brood-rearing female age, hatch date, and weather on brood success and chick survival using an information-theoretic model selection approach. Wind turbine density did not influence early (14-day) brood success, but there was weak evidence for a negative effect of wind turbine density on late (42-day) brood success. There was strong evidence that increasing turbine density within the late brood-rearing home range negatively affected chick survival to 42 days after hatch. The probability of an individual chick surviving to 42 days decreased by 50% when there were ≥10 wind turbines within 2,100 m of the nest. Late brood success and chick survival increased with earlier hatch dates. There was weak evidence for positive effects of post-hatch precipitation on early brood success and chick survival and weak evidence that adult females had higher early brood success than yearlings. Habitat characteristics such as vegetation composition in restored grasslands were poor predictors of offspring survival. Multiple variables, including wind-energy development, are important to Columbian sharp-tailed grouse brood success and chick survival. Wildlife managers should consider the potential for negative impacts of wind-energy development on Columbian sharp-tailed grouse recruitment when addressing wind-energy siting and mitigation.