Nest-switching is an important breeding strategy for multiple-brooded bird species. When deciding whether or not to switch nests for subsequent breeding attempts, pairs must weigh the costs and benefits of various factors related to the number of fledglings of the first breeding attempt, the likelihood of nest predation, and qualities of the nest environment, such as nest ectoparasites and the age of the nest. In this study, we analyzed the predictors and consequences of nest-switching behavior at 6 breeding sites of North American Barn Swallows (Hirundo rustica erythrogaster), where 60% of pairs that raised 2 broods within a season switched nests for a second breeding attempt. Pairs often reused existing (old) nests constructed during previous years, and pairs that settled in old nests for their first breeding attempt were the most likely to switch nests for a second breeding attempt. Contrary to previous studies, nest predation and nest ectoparasitism had no influence on whether or not pairs switched nests. Moreover, second breeding attempts overall had significantly more mites than first breeding attempts, but there was more variation in the change of mite intensities for those pairs that switched nests for a second breeding attempt compared to pairs that did not switch. Furthermore, pairs that switched from one old nest to another nest between breeding attempts decreased the time between first and second breeding attempts when compared to pairs that reused their first nest for a second breeding attempt. Because nest-switching led to greater fledging success for second breeding attempts compared to birds that reused their nests, our results suggest that switching between nests is an adaptive reproductive strategy for Barn Swallows.