Influence of military training on breeding ecology of Bachman's sparrow

Abstract

ABSTRACTAnthropogenic disturbance may cause birds to flush and relocate, abandon breeding sites, experience increased nest failure, or fledge fewer young. Ground‐based military activities are of particular concern for ground‐nesting birds because of the increased risk of nest destruction and trampling of vegetation. We investigated how different intensities of disturbance from ground‐based military training affected reproductive ecology of Bachman's sparrow (Peucaea aestivalis) from 2014–2016, on Fort Bragg Military Installation, North Carolina, USA. We designated 2 training intensity regimes and monitored sparrows at 6 observation areas, 3 in high‐intensity training areas (i.e., foot traffic every 1–3 days) and 3 in low‐intensity training (i.e., foot traffic <1 per month) areas. We compared seasonal productivity metrics and daily nest survival between training intensities. Additionally, we compared male sparrow relative abundance and micro‐habitat use between high‐ and low‐intensity training areas. We monitored 106 male territories and located 110 nests opportunistically and by tracking telemetered female sparrows. We used fixed‐radius point counts to estimate relative abundance in each observation area and measured vegetation composition and structure at a subset of 10 locations in each male territory. Seasonal productivity metrics, daily nest survival, relative abundance, and vegetation composition and structure at male locations did not differ between areas with high and low military training intensity. In 2015, 1 sparrow nest was trampled by military personnel, but ≥1 nestling force‐fledged and the nest was considered successful. Bachman's sparrow nesting ecology was not affected by intensity of ground‐based military training activity, likely because activity was sufficiently dispersed across the landscape, even in high‐intensity training areas. We recommend ground‐based training attempts to minimize ground vegetation destruction by dispersing large groups and traversing variable routes when in forested uplands. © 2018 The Wildlife Society.