Songbird response to seismic lines in the western boreal forest: a manipulative experiment

Abstract

Millions of kilometres of seismic lines have been created for hydrocarbon exploration in the boreal forest and their impact on songbirds is unknown. I conducted a replicated before–after control–impact (BACI) field experiment in southern Northwest Territories to evaluate the impact of 6 m wide seismic lines on songbirds. Territories of all birds on six pairs of 12 ha control and treatment plots were mapped for one year before and one year after seismic lines were cut through the treatment plots. The songbird community was not dramatically affected by seismic lines. At the community level, birds did not decline in abundance or move their territories relative to the seismic lines, and they included the seismic lines in their territories. However, ground and shrub nesting species that had territories spanning the seismic lines increased the size of their territories. At the species level, only the Ovenbird ( Seiurus aurocapilla (L., 1766)) showed a consistent response to seismic lines. Ovenbirds declined in abundance, moved their territories away from seismic lines, and were not observed crossing the lines. Pressure on industry from land managers to reduce the width of seismic lines should continue to minimize the impact of these clearings on all species.