Maika, Fawn2024-07-302024-07-302024-06https://unbscholar.lib.unb.ca/handle/1882/38069The spruce budworm (Choristoneura fumiferana, hereafter “SBW”) is a common prey item for insectivorous songbirds. Due to their cyclic nature, SBW outbreaks can severely defoliate frequently harvested tree species. Therefore, lepidoptera-specific insecticides like Bacillus thuringiensis var. kurstaki (Btk) are used to suppress their populations and associated impact. I examined the indirect effects of Btk on the diet of two species of wood-warblers that specialize in foraging on SBW: the bay-breasted warbler (Setophaga castanea) and Cape May warbler (Setophaga tigrine). Using stable isotope analysis of warbler feces in control and Btk sites pre- and post-insecticide application, I found no significant difference in the proportion of Lepidoptera in the diets of SBW specialists between treatments. Both species showed a consistent consumption in Btk sites post-application, with Hemiptera being the main dietary component across treatments and sampling periods. Individuals in Btk sites may need to increase foraging activity/effort to maintain Lepidoptera consumption.xii, 77electronicenhttp://purl.org/coar/access_right/c_abf2master thesisNocera, Joseph J.Forestry and Environmental Management