Seed Availability and Bird Occurrence in Freshly Drilled Onion and Carrot Fields in Brazil

Abstract

Agricultural landscapes in Brazil provide habitat to various bird species, some of which may be exposed to pesticide-treated seeds that have not been fully incorporated into the soil during drilling. Understanding the dynamics and interactions between birds and freshly drilled fields is crucial for developing sustainable farming practices that balance agricultural food production with wildlife conservation. This study investigated the presence and abundance of birds and the availability of pesticide-treated seeds in four onion fields and seven carrot fields in the Brazilian State of Minas Gerais. Bird surveys were conducted using scan sampling and point count methods to observe diversity and behavior before and after crop drilling. For carrot and onion fields, the study found that seed incorporation rates varied according to the distance from the field edges, with close to the edge having lower rates. In carrot fields, bird monitoring showed a decrease in observed species and individuals on the day of drilling, with an increase in bird sightings after drilling. In onion fields, similar trends were observed, with the species composition changing after drilling and a significant decrease in species abundance on the day of drilling. None of the species found foraging in the field after drilling were granivorous or omnivorous. These findings indicated that carrot and onion fields offer limited food sources for granivore bird species due to high seed incorporation rates and intensive seedbed preparation. The research suggests that freshly drilled carrot and onion fields are generally unattractive to foraging birds, with low seed exposure and a reduced likelihood of contact with pesticides applied as a seed treatment.