Availability of Pesticide-Treated Seeds and Bird Occurrence in Freshly Drilled Onion and Carrot Fields in Brazil

Abstract

Agricultural landscapes in Brazil provide habitat to various bird species, which may be exposed to pesticide-treated seeds that have not been incorporated into the soil during drilling. Understanding the dynamics and interactions between birds and drilled fields is crucial for developing sustainable farming practices that balance agricultural food production with wildlife conservation. This study focused on the attractivity of freshly drilled onion and carrot fields to birds and the potential exposure of birds to the pesticide-treated onion and carrot seeds available on the soil surface after drilling in Minas Gerais, Brazil. Bird surveys were conducted using scan sampling and point count methods to assess diversity and behavior before, on the day of drilling, and after drilling. Carrot fields showed a decrease in observed species and individuals on the day of drilling, with an increase in bird sightings after drilling. Similar trends were observed in onion fields, with the species composition changing after drilling and a significant decrease in abundance on the day of drilling. None of the species found foraging in the field after drilling were granivorous or omnivorous. Seed exposure was assessed by counting available seeds on the soil surface at different timepoints after drilling. Seed exposure was higher in the field border than in the field center. These findings indicate that carrot and onion fields offer limited food sources for granivore bird species probably due to low seed availability and intensive seedbed preparation. The research also suggests that freshly drilled carrot and onion crops are unattractive to foraging birds, with low seed exposure and a reduced likelihood of contact with pesticides applied as a seed treatment.