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PFAS Exposure Was Linked to Oxidative Stress in Starling Chicks, but Not to Similar Changes in Great Tits

Two common starling chicks at a nest opening in a stone wall
Research: Physiology, Molecular biology & biochemistry · Conservation: Threats

Birds breeding near a fluoropolymer plant in northwestern Italy carried far more PFAS in their eggs than birds from an agricultural reference area, but the physiological response differed between species. PFAS — per- and polyfluoroalkyl substances — are a large group of highly persistent synthetic fluorinated chemicals; several can accumulate in living organisms and move through food webs, making transfer into bird eggs biologically relevant. Common starling (Sturnus vulgaris) nestlings near the plant showed signs of oxidative stress, while the analysis did not support similar clear changes in the same measured stress markers in great tit (Parus major) nestlings.

The researchers screened eggs for 38 older and newer per- and polyfluoroalkyl substances (PFAS). Twenty-one were detected. Total concentrations reached as much as 6,576 nanograms per gram fresh weight in great tit eggs and 1,451 nanograms per gram in starling eggs, and levels near the plant were up to ten times those in the reference area. Chlorinated perfluoropolyether carboxylic acids, a group of newer PFAS associated with fluoropolymer production, dominated the contamination profile.

PFAS in eggs documented maternal transfer

Finding PFAS in eggs shows that compounds accumulated by adult females had been transferred into the eggs before hatching. The researchers then measured antioxidant and detoxification systems in nestling blood together with lipid peroxidation, which indicates oxidative damage to fats in cells.

Starling and great tit nestlings responded differently

The analysis did not support clear differences in the measured oxidative-stress markers between areas for great tit nestlings. That does not demonstrate that PFAS had no biological effect in great tits; it means that this study did not detect the same oxidative-stress pattern measured in starlings. Starling nestlings near the plant, however, had altered antioxidant defences and increased lipid peroxidation. The authors interpret this combination as evidence of oxidative stress, and lipid peroxidation in starlings was also positively associated with several PFAS measured in eggs from the same nest boxes.

The contrast shows why contaminant concentration alone does not necessarily predict the same biological effect in different species. The paper notes that starlings and great tits differed in their PFAS profiles, including a greater contribution of long-chain compounds in starling eggs, and calls for further field studies of how PFAS mixtures move through food webs and affect free-living wildlife.

Sources and image credit

  1. Parolini, M., et al. (2026). Exposure to PFAS induced differential oxidative stress-related responses in nestlings of two resident passerine birds nearby a fluoropolymer production plant. Environmental Pollution, 128979.Peer-reviewed primary study published online 18 August 2026. Eggs of great tits and common starlings near a fluoropolymer plant in northwestern Italy contained much higher PFAS concentrations than eggs from a reference area; oxidative-stress responses differed between the two species.
  2. PubMed — Exposure to PFAS induced differential oxidative stress-related responsesBibliographic record and abstract confirming the publication date, PFAS concentrations and species-specific oxidative-stress results.

Image: Common starling (Sturnus vulgaris) chicks at a nest opening in a stone wall in Clarinbridge, Galway, Ireland, 22 May 2011. Photo: Eoin Gardiner / Flickr via Wikimedia Commons. CC BY 2.0. Representative image; not birds from the Italian PFAS study. · CC BY 2.0 · Source

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Physiology

SPECIES IN THIS STORY

Species in this story

Great Tit Parus major Explore species Common Starling Sturnus vulgaris Explore species

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