Abstract: The spatial distribution and breeding behavior of neighboring birds (conspecific and heterospecific) may influence reproduction and the effects differ across species. In this study, we investigated intra- and inter-specific spatial distribution of breeding via artificial nestboxes and examined whether overlap with neighbors affected reproductive success of the focal breeding pair. Regarding spatial distribution, Varied Tits (Sittiparus varius) and Cinereous Tits (Parus cinereus) showed similar pattern: distances of nestboxes containing conspecific tits were greater than those with heterospecific ones. In terms of breeding behavior, reproductive success was not significantly related to the distance from their neighbor’s nest. The reproductive success of Varied Tits was significantly related to that of their neighbors, while in Cinereous Tits, no strong link was found to any recorded reproductive behavior of the neighbors. These findings explain spatial variation in nest site selection of Varied Tits and Cinereous Tits. Reproductive success rate of Varied Tits is affected by that of the neighbors while that of Cinereous Tits is not. The results highlight that there are differences in reproductive outcome among related species and offer suggestions on the use of artificial nestboxes in experiment and conservation programs.