Chestnut-collared longspurs reduce parental care in the presence of conventional oil and gas development and roads

Abstract

Anthropogenic disturbances such as energy extraction may affect numerous behavioural strategies, including competition for optimal nesting sites and predation risk avoidance. Impacts may result either from the structures themselves, or from associated anthropogenic noise and activity. Using surveillance cameras, we recorded behaviours of chestnut-collared longspurs, Calcarius ornatus, a threatened grassland songbird, at nests in a region of dense conventional oil development to determine whether increasing proximity to oil structures and roads had an impact on parental care and productivity. After behavioural analyses, we recorded age and size of breeding longspurs to test the alternative hypothesis that infrastructure and roads alter population demographics, which could in turn affect parental care. Parental care was consistently reduced near oil structures and roads, with additional effects attributed to noise and human activity. Females reduced parental care near roads, whereas males were more sensitive to noise and activity. While adult females were heavier and older near wells, they were smaller near roads; male morphometrics were independent of distance to roads or wells. Fewer offspring successfully fledged at nests near roads, and these offspring fledged at an older age, perhaps as a result of decreased care. Our results suggest that energy development in grasslands impacts parental care and alters demographic distributions. Increased perceived risk may explain some of the observed decrease in parental care; songbirds' reproductive strategies are altered near roads and energy infrastructure, potentially leading to decreased fitness. Mitigation measures should reduce effects of the presence of well infrastructure, roads, noise and activity to be effective.