Research had already shown that the intensification of agriculture, and by extension the use of herbicides and insecticides such as glyphosate, were responsible for the decline in farmland birds over several decades. However, the impact of fungicides, used in particular to combat mildew and powdery mildew, remains largely unstudied.
To do this, the scientists compared the reproductive success of a control group of house sparrows with that of a group exposed to tebuconazole in proportions similar to real-life conditions. Although exposure to this fungicide did not affect the health of the second group, dates of breeding entry, number of eggs laid or hatching success, adverse effects were observed on the chicks after hatching. The chicks, particularly the females, showed altered growth (almost 10% smaller) and twice the mortality rate of the young sparrows after fledging from the nest than the control group, rising from 20% to 47%.
Further studies are still needed to better document the contamination of wild animals by this substance and the physiological disturbances it can cause.
1 From the Centre d’études biologiques de Chizé (CNRS/La Rochelle University) and the Chrono-environnement Laboratory (CNRS/Marie et Louis Pasteur University).
Chronic exposure to tebuconazole impairs offspring growth and survival in farmland birds: An experiment in captive house sparrows. Pauline Bellot, François Brischoux, Clémentine Fritsch, Loula Lièvre, Cécile Ribout, Frédéric Angelier. Environmental Research, March 29, 2025. https://doi.org/10.1016/j.envres.2025.121321
