In my experience out at the arboretum, red-breasted nuthatches excavate their cavities and white-breasted nuthatches use existing natural cavities or nest boxes. This red-breasted nuthatch is working away on a Douglas-fir snag. I could hear the muffled hammering as it carved away. After a minute or less, it would appear in the entrance to the cavity with a mouthful of shavings. Sometimes it released the shavings from the entrance and sometimes it would pop out onto the side of the tree and let them go. The wood appears to have become very soft as the shavings looked like dust falling through the air. I think the nuthatch was excited about the consistency of the wood. It seemed to be vigorously and merrily chiseling away its new nest and it occasionally gave a toot from the entrance which sounds like a miniature tin horn. The male and female both excavate the nest with the female doing more. That said, the bold markings on this one appear to be the male, and males without mates may begin excavating several cavities at once in an attempt to attract a female. I need to go back and see if this male is in a relationship. After the cavity is constructed, she will line the bottom with soft materials such as fine grasses, strips of bark, fur, or feathers. Interestingly, I read that they will spread sap around the entrance to their nests. I love this little bird! I hope you are getting in some good birding so far this spring.
