Dermal death? New publication on birds’ insecticide exposure
New publication out: "Acute mortality in sand martins (Riparia riparia) and barn swallows (Hirundo rustica) linked to dermal or inhalation pyrethroid insecticide exposure" by Aafke Saarloos, Maarten Schrama, Henrik Barmentlo, Judith van den Brand, Natashja Ennen-Buijs, Reina Sikkema, Wouter Bakker, Tijs van den Berg, and Nico van den Brink (Wageningen University) in Environmental Chemistry and Ecotoxicology.
The study investigates acute mortality incidents in swallow colonies in the Netherlands. The findings suggest a significant "blind spot" in how we assess chemical safety for birds.
The team examined swallows that exhibited severe neurological symptoms, including loss of muscle tone and coordination. Wageningen University & Research performed necropsies and comprehensive testing, ruling out viral infections, physical trauma, or common diseases. Screening for 648 different pesticides revealed the ubiquitous presence of two specific insecticides, permethrin and tetramethrin, on the feathers of the birds sampled.
Key Findings:
🗺️ Exposure Route: While the chemicals were low or absent in the birds' stomachs (ruling out ingestion), they were found in the brain tissue and on the feathers.
☠️ The Cause: The study concluded that the swallows died from acute neurotoxicity caused by dermal (skin) contact or inhalation, rather than eating contaminated food.
🕳️ The Gap: Current regulatory risk assessments for birds and mammals focus almost exclusively on oral exposure.
This research demonstrates that dermal and inhalation routes can be lethal, yet they are currently overlooked in environmental safety standards. Without accounting for how birds "touch and breathe" their environment, we may be significantly underestimating the lethal risks pesticides pose to wildlife.
👁️ Read now! ➡️➡️ https://doi.org/10.1016/j.enceco.2026.03.019
The paper has also got attention from Dutch media, and team members Aafke Saarloos and Nico van den Brink were on the radio:
Insecticiden en de plotselinge sterfte van zwaluwen | NPO Radio 1