We describe what we believe to be the first recorded instance of an adult Poecile atricapillus (Black-capped Chickadee) feeding the young of a different species. On 25 June 2017, we observed a Black-capped Chickadee feeding 3 Catharus guttatus (Hermit Thrush) nestlings. We recorded a video of this behavior the following day, in which the adult Black-capped Chickadee delivered food to the Hermit Thrush nestlings 12 times in 105 min of continuous recording. The Black-capped Chickadee also removed fecal sacs from the nest. At the end of this video, 1 of the nestlings fledged. We did not observe an adult Hermit Thrush feeding the nestlings during the entire recording. The considerable differences in body size, nesting strategy, and nestling growth rate between these 2 species comprise a unique instance of interspecific parental feeding that resulted in successful fledging.