Courtship displays are usually carried out among the branches and tops of coniferous trees, where the birds are difficult to observe. Both adults work to excavate a nest cavity, most commonly in a rotten stub or branch of a dead tree. Nest boxes are occasionally used. The average height of the nest is 15 feet off the ground. The nest is made of grass, rootlets, moss, shredded bark, plant fibers, hair, and fur.
Adults typically smear tree pitch around the entrance of their nest cavity, even on a nest box.
The pitch, as a rule, is generously laid on, sometimes for a distance of several inches all around the hole. This activity, which is carried on throughout the nesting period, is thought to deter insects, small mammals, and other birds from entering the nest cavity. Several observers have noted that Red-breasted Nuthatches have a habit of flying straight into the entrance hole, without alighting on the outside of the cavity first, perhaps to avoid the pitch smeared around the hole. Egg Laying Clutch sizes range from four to seven eggs, with five or six being the usual number. Incubation is probably done by the female alone.