Date of Award

2026

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Wildlife Ecology and Conservation (MS)

Administrative Home Department

College of Forest Resources and Environmental Science

Advisor 1

Jared D. Wolfe

Committee Member 1

Sarah R. Hoy

Committee Member 2

Kristin E. Brzeski

Abstract

Habitat quality is often difficult to measure directly, particularly for songbirds occupying heterogeneous landscapes and experiencing shifting energetic demands across the annual cycle. Physiological indicators provide an objective, mechanistic basis for inference by revealing whether birds are depositing or mobilizing energy at the time of capture. β-hydroxybutyrate and triglycerides are widely used as indicators of catabolic and anabolic state, reflecting fasting and fat deposition, respectively. I quantify variation in these metabolites across a community of passerines and near-passerines captured in Michigan’s western Upper Peninsula across life-cycle phases. I assess whether metabolite distributions differ among phases and among banding stations, identify the periods in which spatial patterns are most interpretable as signals of habitat quality, and evaluate which species and metabolite metrics most reliably reproduce station-level differences. Our broad sampling provides baseline metabolic profiles across species, and across life cycle phases, producing the first metabolite library across migratory and resident species.

Available for download on Saturday, April 10, 2027

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