Pest control services on farms vary among bird species on diversified, low-intensity farms

Avian species provide pest control services in some agricultural systems, which may incentivize farmers to conserve natural habitats for native biodiversity. A critical component of this equation, however, is verifying that avian species are consuming potential pest species in the agricultural ecosystems. We used a DNA metabarcoding approach to determine the frequency of pest presence in songbird fecal samples collected from birds caught on diversified, low-intensity farms in New England, USA, during the bird breeding season. Twelve species of insect pest were identified in fecal samples, and across all songbird species 12.6% of samples included DNA from at least one pest. Frequency of pest presence depended on songbird species, with Common Yellowthroats and Gray Catbirds eating pests more frequently than Song Sparrows. Pests were also more frequently found in fecal samples collected from hatch-year birds and birds caught later in the year. Although we observed a lower frequency of pest consumption than observed in previous comparable research, growers can likely improve pest control by songbirds by promoting the woody, non-crop habitat types preferred by insectivorous species, in our system specifically Gray Catbirds and Common Yellowthroats.