Influence of Habitat Structure, Landscape Compo-sition, and Food Availability on the Distribution andAbundance of Eastern Whip-Poor-Wills

The eastern whip-poor-will (Antrostomus vociferus) isan aerial insectivore that has experienced drastic de-clines across much of its range in recent decades. Re-ductions of insect populations and habitat degradationare hypothesized to be contributing to their decline.To help understand proximate causes of this decline,we studied habitat use and food availability of whip-poor-wills in Illinois. We performed nocturnal surveysto assess occupancy and abundance of whip-poor-willsacross a broad range of forested sites in Illinois and ex-amined habitat use in radio-tracked birds. Along surveyroutes, we sampled for nocturnal insects with UV-lighttraps to evaluate whether moth and beetle abundanceor diversity predicts whip-poor-will occupancy, and wecollected additional data related to habitat characteris-tics, light pollution, and pesticide load. Further, weexamined fecal samples from 115 captured whip-poor-wills using DNA metabarcoding to determine the com-position of their diet. Whip-poor-will occupancy was37%, and landscape-level forest cover was a major de-terminant of whether sites were occupied . Based on ourradio-telemetry work, whip-poor-wills tended to spendactive periods in areas with more open canopies and lessdense understories compared to roosting sites. Fromlight trap data, moth abundance varied widely amongsites and was related to abundance of whip-poor-wills. In diet analyses, whip-poor-wills were mainly eat-ing moths (86% of samples), cockroaches (9%), andbeetles (6%). Our results suggest that food availabil-ity and habitat structure may be determining the distri-bution and abundance of whip-poor-wills and are likelyimportant factors for crafting management plans for thisspecies.