We documented Red-breasted Nuthatches (Sitta canadensis) in the Berkeley Hills of coastal central California successfully using a nest box in 2021 and 2022, and successfully double brooding in 2022. Although we can’t be certain the individuals responsible for the two broods in 2022 were the same, we never saw more than two adults. In both years, we also observed the nuthatches applying resin to the outside of the box, most conspicuously to create a mass that included some grass at the base of the entrance hole, somewhat reducing its diameter (Figure 1).