We provide data on three instances where Tree Swallows (Tachycineta bicolor) that fledged from the same nest (broodmates) eventually bred together in subsequent years. Two instances were detected in Ontario and a third was detected in Nova Scotia. Based on demographics at the times of each event, we estimated probabilities of these broodmate pairings as approximately 1 in 16,000, 1 in 5600, and 1 in 29,000, respectively, whereas the number of identified pairs in the populations was less than 65 in each case. Thus, inbreeding occurred at a higher frequency than expected by chance. We cannot distinguish whether these identical natal dispersal responses arose from similarity in genes or in rearing environments.