Mountain bluebirds are cavity nesters and can become very partial to a nest box, especially if they have successfully raised a clutch. They may even reuse the same nest, though not always. These birds will not abandon a nest if human activity is detected close by or at the nest. Because of this, they can be easily banded while they are still in the nest. The threats of predation for those that dwell in nesting boxes are mostly from house cats, raccoons, and the parasitic blowfly, "Apaulina stalia".