Masters Theses
Date of Award
12-2024
Degree Type
Thesis
Degree Name
Master of Science
Major
Wildlife and Fisheries Science
Major Professor
David A. Buehler
Committee Members
David Buckley, Jeff Atkins, Darin mcneil
Abstract
The Swainson’s Warbler is a Nearctic-Neotropical songbird that breeds across the southeastern United States in two main, geographically-disjunct regions: the Southeastern Coastal Plains and the Appalachian Mountains. In Tennessee, the Swainson’s Warbler is a species of conservation concern, but the breeding territory characteristics and distribution of this species in the Appalachian Mountain portion of its range remain largely unstudied. Our objectives for this study were to 1. identify vegetation metrics that drive Swainson’s Warbler territory selection, 2. model Swainson’s Warbler abundance on the 88,000-ha, southern ranger districts of the Cherokee National Forest, 3. inform Swainson’s Warbler management in the southern Appalachian Mountains. We conducted Swainson’s Warbler point-count surveys in 2022 and 2023 along 99 km of secondary roads on the forest and located a total of 125 unique individuals, with 1.26 territories/km. We randomly selected 60 territory and 60 absence plots where we collected on-the-ground and LIDAR-derived vegetation metrics and analyzed all metrics in a resource-selection framework via logistic regression. The best-supported model contained percent understory (β [beta] = 7.34 ± [plus-minus] 1.45 SE, 95% CI [4.28, 10.4]) and visual obstruction (β [beta]= 0.56 ± [plus-minus] 0.18 SE, 95% CI [0.18, 0.95]). Additionally, we used multinomial N-mixture models with remotely-sensed covariates to determine which covariates best predicted Swainson’s Warbler relative abundance. The best-performing model included slope, mean outer canopy height, topographic wetness index, and percent of first returns below 1 m. We estimated there was 3,520 ha of potential Swainson’s Warbler habitat on the southern ranger districts of Cherokee National Forest, 55% of which was within 200 m of roads, and therefore accessible to monitoring via roadside counts. An estimated 26% of potential habitat was located within 30 m of streams and was thus affected by current streamside management zone guidelines. This study documented the largest known breeding population of Swainson’s Warblers in the Appalachian Mountains. Knowledge of the key characteristics linked to territory selection and distribution of this species on a landscape may inform management for this priority songbird species in the Appalachian region.
Recommended Citation
Rader, Dawson W., "Habitat use and relative abundance of the Swainson’s Warbler (Limnothlypis swainsonii) in the Appalachian Mountains on Cherokee National Forest, Tennessee. " Master's Thesis, University of Tennessee, 2024.
https://trace.tennessee.edu/utk_gradthes/12824
