Ingested Plastic in the Great Northern Diver, the Common Loon (Gavia immer)

Plastic pollution and its impact on water-reliant avifauna is a global, pervasive issue. We evaluated necropsy data of Gavia immer (Common Loon) from freshwater and marine environments in the northeastern US from 2011 to 2022, and found 16.2% (106/654) had ingested plastic items (macroplastics). We examined Common Loons stranded from 2020 to 2022, quantified macroscopic plastic items in detail, and processed the ingesta for suspected microplastics. We found macroplastics in 20.7% (11/53) and suspected microplastic particles, predominately clear fibers, in 100% (37/37) of the Common Loons. While we found no evidence that sex, mass, or geography correlated with microplastic load, both macroplastics and suspected microplastics were widespread and prevalent in Common Loon ingesta in the northeastern US. © 2025 Humboldt Field Research Institute. All rights reserved.