Agricultural expansion threatens biodiversity, but promoting native species like insectivorous birds in agricultural landscapes could benefit both biodiversity and farm productivity alike. Recently, some California winegrape growers have used nest boxes to promote biodiversity and attract insectivorous birds in an effort to help control insects. While early findings suggested nest boxes have a positive impact on bird functional richness and abundance, later research found no significant effect on avian community composition or pest control. This project addresses research needs using a before-after-control-impact experiment involving winegrape vineyards in Napa Valley, California. The objectives of this study are to (i) examine how habitat and landscape composition influence bird communities and (ii) how the addition of nest boxes affects insectivore abundance. Avian point counts were conducted for two seasons on 20 vineyards, 10 with existing nest boxes and 10 with nest boxes added between field seasons. We hypothesize that the addition of songbird nest boxes to winegrape vineyards attracts insect-eating birds, and these effects are mediated by local and landscape level characteristics. We also hypothesize that the beneficial effects of within-farm habitat complexity on bird abundance and diversity are mediated by the composition of the surrounding landscape.