Standing dead trees or dead parts of trees play an important role in the ecosystem, including providing places for nests for various birds. One of those birds are the nuthatches, which are one of the few non-woodpeckers that excavate their own nest cavities. With the Red-breasted Nuthatch, both of their sexes will help to build a nest, but the female will do more than the male. But the males will feed the females while the females work on the nest. Aspen trees, with their softer wood, are their preferred tree for nest building when available. The cavity can be up to 20 centimeters deep, taking up to 18 days to excavate. For the bed inside the nest, various materials can be used, including grass, bark strips, and pine needles and lined with fur, feathers and fine grasses and bark stripes. Both sexes will apply conifer resin to the entrance, sometimes with a piece of bark. It’s thought that this is done to keep out predators. The nuthatch avoids the resin by diving straight through the hole. With the resin, the home is ready for the family with a security measure.