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Alec Woolf, MS, is a 2024 graduate of the MS Program in Environmental Studies at Antioch University New England

Thesis Committee:

Michael Akresh, PhD, Committee Chair

Jeffrey Ritterson, MS, Committee Member

Keywords

brown thrush, Toxostoma rufum, habitat, preferences, habitat survey, New England, Northeastern United States

Document Type

Thesis

Publication Date

2024

Abstract

Early successional habitat and related species are in decline in the Northeastern United States. One species of shrubland bird that is declining in the northeast is the Brown Thrasher, considered a species of conservation concern in several states such as New Hampshire, Rhode Island, Connecticut, New York, Vermont, and New Jersey. However, few studies have focused on examining Brown Thrasher habitat preferences. The purpose of this study was to evaluate Brown Thrasher associations with early successional habitat adjacent to farmland, within deciduous forests, and within pine barrens. I conducted systematic point count surveys with playback to assess thrasher occupancy and habitat use. I surveyed birds at 47 points in 25 sites throughout inland Massachusetts between 2021-2023. Point counts were conducted 2-3 times per point between mid to late April and mid-May to maximize detection during this period of higher levels of singing activity for this secretive species. In addition, I examined vegetation characteristics at each point and recorded all avian species detected during each point count. Vegetation sampling was conducted at each point between early June through August. I used an occupancy model to determine the detection and occupancy probability of Brown Thrashers. I found Brown Thrashers had higher occupancy in shrublands within pine barrens compared to shrublands within deciduous forest and shrubby areas adjacent to agricultural fields. Vegetative and avian species varied among habitats. Early successional habitat adjacent to farmland had the least amount of canopy cover and the least amount of vegetation structure among the habitats in this study. The early successional habitat within pine barrens had the highest basal area and largest amount of course woody debris among the habitats. The environmental variables examined in the analysis (e.g., canopy cover, basal area) did not impact occupancy or detection probability. My findings suggest shrubland within pine barrens is crucial habitat for Brown Thrasher and future habitat management and restoration of shrublands in pine barrens would benefit the Brown Thrasher as well as other pine barren specialist species.

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