Are oil and natural gas development sites ecological traps for nesting killdeer?

Abstract

Extraction of oil and natural gas is an emerging source of anthropogenic disturbance that threatens wild populations and important wildlife habitats. We compared daily nest survival estimates of killdeer Charadrius vociferous at graveled oil pads to those that nested on native grass cover in western Oklahoma, USA in 2015 and 2017. We conducted weekly searches for nesting killdeer around oil pads and in pastures (grass cover) at the Packsaddle Wildlife Management Area April-June. Killdeer showed a strong selection for graveled oil pad over grass fields with 64% of all nest attempts occurring on oil pads. A higher proportion (64%) of the nests we found were in the gravel substrates of oil pads, and daily nest survival estimates for oil pad nests were lower than our estimates for nests in grass substrates. We also identified a difference in edge effects between the two nesting substrates with the probability of nest survival on oil pads highest closer to the edge of the patches and the probability of nest survival in grass cover highest in the interior of the patches. This is an indication that risk of nest failure on oil pads increased towards areas of high human use: Nest failure on oil pads was almost entirely due to destruction by moving vehicles and by oil workers performing routine operations at well sites. Our results demonstrate that modified landscapes attract native species but could function as ecological traps. Management efforts to reduce the effect of oil and natural gas development or similar forms of human land use modifications on co-occurring nesting birds will benefit from reduction in habitat conversion and incorporation of natural gas developments into conservation planning.