Conventional oil and natural gas infrastructure increases brown-headed cowbird ( Molothrus ater ) relative abundance and parasitism in mixed-grass prairie

Abstract

The rapid expansion of oil and natural gas development across the Northern Great Plains has contributed to habitat fragmentation, which may facilitate brood parasitism of ground-nesting grassland songbird nests by brown-headed cowbirds (Molothrus ater), an obligate brood parasite, through the introduction of perches and anthropogenic edges. We tested this hypothesis by measuring brown-headed cowbird relative abundance and brood parasitism rates of Savannah sparrow (Passerculus sandwichensis) nests in relation to the presence of infrastructure features and proximity to potential perches and edge habitat. The presence of oil and natural gas infrastructure increased brown-headed cowbird relative abundance by a magnitude of four times, which resulted in four times greater brood parasitism rates at infrastructure sites. While the presence of infrastructure and the proximity to roads were influential in predicting brood parasitism rates, the proximity of perch sites was not. This suggests that brood parasitism associated with oil and natural gas infrastructure may result in additional pressures that reduce productivity of this declining grassland songbird.

Landscape heterogeneity influences the response of grassland birds to energy development

“…Various mechanisms have been proposed explaining changes in grassland bird abundance surrounding infrastructure. These include: 1) variability of vegetation around infrastructure including invasive species (Kalyn Bogard and Davis 2014, Ludlow et al 2015), 2) avoidance of predators and nest parasites that may be more abundant near development (Hethcoat and Chalfoun 2015, Bernath‐Plaisted et al 2017), 3) avoidance of increased human activity (Holloran et al 2015), 4) chronic noise (Francis et al 2011), and 5) innate avoidance or attraction to tall structures in an otherwise open landscape (Grant et al 2004). While our analysis was not designed to test these alternatives, heterogeneity‐based management can influence a number of these mechanisms, particularly vegetation structure, potentially explaining the variation in response to infrastructure by species such as eastern meadowlarks, dickcissels and grasshopper sparrow across patches with different times since fire.…”

Varying dataset resolution alters predictive accuracy of spatially explicit ensemble models for avian species distribution

“…Two species were always better with statewide models (Brown‐headed Cowbird and Dickcissel). The cowbird is strongly dependent on habitat structure (Benson et al, ; Bernath‐Plaisted, Nenninger, & Koper, ), but these variables are not what is measured by the predictor layers that we used. Dickcissel is known for its semi‐nomadic movement patterns (Temple, ); as such, neither species may be as dependent on local climatic variation mapped by the BioClim predictor inputs.…”

“…The cowbird is strongly dependent on habitat structure (Benson et al, ; Bernath‐Plaisted, Nenninger, & Koper, ), but these variables are not what is measured by the predictor layers that we used. Dickcissel is known for its semi‐nomadic movement patterns (Temple, ); as such, neither species may be as dependent on local climatic variation mapped by the BioClim predictor inputs. The inconsistencies in the remainder of the species suggest that a larger sample of species and predictor resolutions is needed to compare why models are appropriate for given situations.…”

Rat snakes, cowbirds, and vines lower passerine nest survival in remnant bottomland hardwood forests in east-central Arkansas, USA

“…Specifically, cowbirds are thriving due to fragmentation of our forested system (e.g., Bernath-Plaisted et al 2017) and presence of livestock (e.g., Goguen and Mathews 2001) especially along the levees surrounding the periphery of our study sites. These levees are, in part, managed by the agencies responsible for the administration of the forested reserves included in our study; thus, livestock use theoretically could be phased out.…”