The Red-breasted Nuthatch’s diet changes depending on the season. In the summer, it eats mostly insects, occasionally even fly-catching, while in the winter, it switches to conifer seeds. At feeders it will take sunflower seeds, peanut butter, and suet. It often wedges food pieces in bark crevices in order to break them up with the bill (as opposed to holding the food in their feet, like the black-capped chickadee does).
The bird is regularly observed using a small chips of bark, small twigs, and pine needles held in its beak as tools to dig for insects. The nuthatch exhibits other curious behaviors such a cooperative groups where groups of 3-5 adults provide care at a single nest. Recent genetic assessments suggest some of the putatively non-breeding adults associated with these groups may actually breed with individuals in neighboring territories. This nuthatch also exhibits a wide range of other social behaviors that include social grooming and male-female duets similar to those observed for the Pygmy Nuthatch.