Nesting Behaviour and Reproductive Success of Sprague’s Pipit (<i>Anthus spragueii</i>) and Vesper Sparrow (<i>Pooecetes gramineus</i>) during Pipeline Construction

Abstract

Industrial activity occurs in the breeding habitat of several species at risk, including the federally threatened Sprague’s Pipit (Anthus spragueii). To evaluate whether oil pipeline construction reduces the productivity of this species, we examined (a) noise levels in relation to distance from the pipeline right-of-way (ROW), (b) the extent to which noise and song frequencies overlapped, (c) the distribution of Sprague’s Pipit nests relative to the ROW, and (d) Sprague’s Pipit reproductive success during exposure to pipeline construction and clean-up activity. We also examined the songs, nest locations, and reproductive success of the Vesper Sparrow (Pooecetes gramineus) for comparison. Study plots (400 × 400 m, n = 30) were established in grassland adjacent to the pipeline ROW or 600 m away from the ROW in similar habitat. Mean maximum noise levels during pipeline activity included frequencies that overlapped the song range of both species and were louder than the recommended 49 dB threshold up to 250 m from the ROW. Sprague’s Pipit nests were evenly distributed across close and distant plots, whereas Vesper Sparrow nests were more abundant within 50 m of the ROW. Sprague’s Pipit daily nest survival rate and the number of young surviving to day 8 both increased with increasing distance from the ROW; and Vesper Sparrow daily nest survival decreased slightly with exposure to pipeline activities. Our findings validate the restricted activity period and indicate that the recommended setback distance of 350 m is a reasonable guideline for pipeline projects.