EFFECT OF DIFLUBENZURON APPLICATION ON EASTERN DECIDUOUS FOREST BIRDS

Conducted a replicated experiment in E West Virginia. Diets of 7 insectivorous bird species and foraging behavior of male red-eyed vireos Vireo olivaceus also were examined. Although caterpillars were less common on treated areas, none of the 21 common bird species was significantly more abundant in untreated plots. Significant differences in the percentage of Lepidoptera larvae in diets were observed for all species examined except worm-eating warbler Helmitheros vermivorus and blue-gray gnatcatcher Polioptila caerulea. Vireo foraging areas (measured in 2 ways) were 3.1 and 2 times larger on treated areas. Differences in diet and foraging behavior were likely related to the decreases in abundance of caterpillars on treated plots. -from Authors