Due to reductions in winter food resources, newly sown cereal seeds have become a key component of many bird species’ diet, but these seeds are often treated with pesticides that may cause toxic effects. We studied the abundance of pesticide-treated seeds available for birds in the field, the pesticides and their concentrations in treated seeds, and the bird species observed in the field that were feeding on these pesticide-treated seeds. The exposure of red-legged partridge to treated winter cereal seeds was characterized through the analysis of crop and gizzard contents of hunted individuals (n=189). Moreover, we measured the contribution of cereal seeds in the autumn–winter diet of partridges in order to assess the potential risk of exposure to pesticide-treated seeds. Up to 30 bird species were observed consuming treated cereal seeds in recently sown fields. Corn bunting was identified as an appropriate focal passerine species for the risk assessment of pesticide-treated seeds. We found that treated seeds were an important route of pesticide ingestion for red-legged partridge; pesticide residues (six fungicides and two insecticides) were found in 32.3% of crops and gizzards. Cereal seeds represented more than half (53.4 ± 4.3%) of total biomass consumed by partridges from October to February. The field exposure data combined with previous studies about the toxicity to partridges of using pesticide-treated seeds point to an unacceptable risk of this practice to farmland birds. Our results suggest that the prophylactic use of pesticide-coated seeds should be avoided.
Source:
Ana Lopez-Antia, Jordi Feliu, Pablo R. Camarero, Manuel E. Ortiz Santaliestra and Rafael Mateo
Journal of Applied Ecology DOI: 10.1111/1365-2664.12668
http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12668/abstract
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