Exploring the impact of a perfluoroalkyl substance (PFAS) and interspecific variation on passerine metabolism (2025-04-04)

Abstract

Integrated study of physiology is essential to better inform risk assessment and management as organisms face compounding stressors, such as environmental contaminants and climate change. Passerines, being a diverse, abundant, and sometimes vulnerable group of birds, warrant further study in their physiological responses to these stressors. We took a novel approach by using field flow-through respirometry to investigate the effects of a perfluoroalkyl substance (PFAS), perfluorooctane sulfonate (PFOS), on the metabolic regulation and thyroid function of Tree swallows (Tachycineta bicolor). Additionally, we examined interspecific differences in metabolic rates and liver weights among three passerine species in northern Minnesota: Tree swallows, House wrens (Troglodytes aedon), and Black-capped chickadees (Poecile atricapillus). We found that PFOS exposure impacts thyroid hormone concentrations in Tree swallows but does not significantly impact metabolic rate or growth. Furthermore, interspecific differences in metabolic rates and liver weights were significant, and liver weight may be better at explaining differences in metabolic rate than mass alone. This integrative study contributes to both an understanding of ecotoxicological impacts of PFAS and a foundation for future comparative physiology studies in passerines.