Accurate measures of reproductive performance in birds are vital to effective conservation and management of populations. We evaluate the effectiveness of a recently proposed method to estimate reproductive performance based upon behavior of breeding birds during responses to Black-capped Chickadee (Poecile atricapillus) mobbing calls. We examined whether responses of Black-throated Blue Warblers (Dendroica caerulescens) to mobbing calls were related to measures of reproductive performance as determined in a nest monitoring study. We found that individuals that were successful reproducers were more likely to exhibit a response to the mobbing calls. Successfully reproducing individuals were more likely to display evidence of reproductive success (e.g., carrying nesting material, carrying food) when they responded to the mobbing call. Observations of reproductive success, however, depended on the distance of the observation to the nest site of the individual. We conclude that responses to mobbing calls have limited utility for discerning variability in reproductive success among territories. However, if the research objective is to obtain coarse comparative estimates of reproductive success at large spatial scales over which reproductive output is likely to be highly variable, then observations generated by the mobbing playback method may suffice.