Old growth Longleaf Pine stand on Fort Bragg, NC
Chapter 1: Effect of military training on Bachman's sparrow reproductive output and abundance
Military bases are committed to managing for the native ecosystems, such as the longleaf pine forests in North Carolina. Yet, training and biological conservation objectives can come into conflict on military installations. For declining species of concern, such as the Bachman's Sparrows, military training may negatively effect breeding ecology. Bachman's Sparrow nest, forage and spend the majority of their time on the ground, making them particularity vulnerable to ground-based training exercises. We compared nest success, reproductive output and abundance across highly impacted areas and less heavily impacted areas. Using radio telemetry and opportunistic nest searching, we located 110 nests between 2014-2016, while simultaneously monitored 120 territories. We additionally conducted repeat visit point counts, to generate abundance estimates under various levels of military training. We did not find a significant affect of military training on Bachman's sparrow reproductive ecology. We did document one nest being trampled, but the nestling force-fledged and the nest was considered successful.
Chapter 2: Bachman's Sparrow occupancy in a continuous longleaf pine forest
Bachman's Sparrows have been described as disturbance obligates and are highly associated with longleaf pine forests in the southeastern United States. Bachman's Sparrows need a frequent prescribed fire regime, approximately once every three years, to maintain a lush herbaceous under-story of grass and forbs, while suppressing the growth of woody shrubs. Furthermore, very little is know about Bachman's sparrow ecology on the northern range limit (e.g North Carolina). We conducted repeat visit point counts to calculate occupancy of Bachman's sparrows on Fort Bragg, North Carolina and to identify micro-scale habitat selection. We found Bachman's sparrows selected for similar habitat as more southerly populations but also uniquely selected for areas adjacent to escape cover.
Side Project: Juvenile Bachman's sparrow survival and habitat selection during the fledgling period
Recent advances in micro-radio transmitters have allowed scientist to track juvenile birds during a life stage that was previously a mystery. Radio telemetry of other passerine birds has revealed unique habitat selection and survival patterns. To date no study has attempted to evaluate survival of juvenile Bachman's sparrows or describe selected habitat. Quantifying survival of juvenile Bachman's sparrows will allow for more accurate population modeling and guide understanding of movement and habitat selection. Current population models use survival estimates from other species or make broad biological assumptions. Preliminary results indicate that fledgling BACS move to dense vegetation, usually found in riparian areas or wildlife openings. Preliminary analysis indicates that juvenile movement is limited to the parents territory and juvenile selected habitat may be limited on the landscape.
In addition to the primary research objectives mentioned above, we re collaborating with researchers with the North Carolina Wildlife Research Commission on a Bachman's sparrow genetics project, with an additional graduate student at North Carolina State University on a nesting ecology project and with a Dorris Duke Conservation Scholar investigating female Bachman's sparrow biology.