Passerine birds as bio-indicators of pesticide levels in farmlands and gardens: mitigation by organic farming and distance from treated fields
Abstract
Both farmworkers and residents living near agricultural areas face adverse health outcomes prevailingly attributed to pesticides. Proximity to intensive agricultural areas may increase exposure, although this association remains debated, partly because collecting human biological samples is difficult. Therefore, identifying relevant bioindicators of environmental pesticide exposure could provide an alternative approach, and passerine birds are promising candidates given their close coexistence with humans. Here, we compared pesticide levels and profiles in passerines from farmland hedgerows and residents' gardens within the same rural area, and explored the effects of two mitigating components, assuming lower pesticide pressure with a higher percentage of organic farming (%OF) around hedgerows and with greater distance from the nearest treated crop for gardens. Blood samples were collected from 217 individuals across 11 species, and 111 pesticide residues were analysed. Contamination levels and profiles did not differ between farmlands and gardens, suggesting pervasive pesticide occurrence driven by environmental persistence and broad-scale dispersal. In farmland, model-estimated pesticide concentrations declined by 61.3% (95% CI: 32.5-77.8%) as %OF increased from 0 to 100%. In gardens, the model-estimated number of compounds and pesticide concentrations decreased with distance to the nearest conventional plot by 30.1% (95% CI: 6.8-47.6) and 70.1% (95% CI: 49.2-82.4), respectively. These effects were species-dependent, suggesting that certain species, such as the European robin, are more relevant indicators of local pesticide levels, likely due to their smaller home ranges. By showing that bird contamination reflects local agricultural practices and proximity, this study supports using passerines as effective sentinels of local environmental pesticide pressure, offering a valuable proxy for assessing ecological exposure in environments shared with human populations.
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BibTeX
@article{bailly2026passerine,
title = {{Passerine birds as bio-indicators of pesticide levels in farmlands and gardens: mitigation by organic farming and distance from treated fields}},
author = {Audrey Bailly and Karine Monceau and Maurice Millet and Etienne Debenest and Sabrina Gaba and Vincent Bretagnolle and Jérôme Moreau},
journal = {Environment International},
year = {2026},
month = oct,
doi = {10.1016/j.envint.2026.110574},
url = {https://hal.science/hal-05838401v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Passerine birds as bio-indicators of pesticide levels in farmlands and gardens: mitigation by organic farming and distance from treated fields
AU - Audrey Bailly
AU - Karine Monceau
AU - Maurice Millet
AU - Etienne Debenest
AU - Sabrina Gaba
AU - Vincent Bretagnolle
AU - Jérôme Moreau
PY - 2026
DA - 2026/10/25
JO - Environment International
DO - 10.1016/j.envint.2026.110574
UR - https://hal.science/hal-05838401v1
AB - Both farmworkers and residents living near agricultural areas face adverse health outcomes prevailingly attributed to pesticides. Proximity to intensive agricultural areas may increase exposure, although this association remains debated, partly because collecting human biological samples is difficult. Therefore, identifying relevant bioindicators of environmental pesticide exposure could provide an alternative approach, and passerine birds are promising candidates given their close coexistence with humans. Here, we compared pesticide levels and profiles in passerines from farmland hedgerows and residents' gardens within the same rural area, and explored the effects of two mitigating components, assuming lower pesticide pressure with a higher percentage of organic farming (%OF) around hedgerows and with greater distance from the nearest treated crop for gardens. Blood samples were collected from 217 individuals across 11 species, and 111 pesticide residues were analysed. Contamination levels and profiles did not differ between farmlands and gardens, suggesting pervasive pesticide occurrence driven by environmental persistence and broad-scale dispersal. In farmland, model-estimated pesticide concentrations declined by 61.3% (95% CI: 32.5-77.8%) as %OF increased from 0 to 100%. In gardens, the model-estimated number of compounds and pesticide concentrations decreased with distance to the nearest conventional plot by 30.1% (95% CI: 6.8-47.6) and 70.1% (95% CI: 49.2-82.4), respectively. These effects were species-dependent, suggesting that certain species, such as the European robin, are more relevant indicators of local pesticide levels, likely due to their smaller home ranges. By showing that bird contamination reflects local agricultural practices and proximity, this study supports using passerines as effective sentinels of local environmental pesticide pressure, offering a valuable proxy for assessing ecological exposure in environments shared with human populations.
SN - 0160-4120
ER -