Flammulated Owls (Psiloscops flammeolus) are small insectivorous raptors that breed in ponderosa pine ecosystems in Western North America. These owls depend on old-growth ponderosa pine forests for nesting, foraging, and day-roosting habitat. Old-growth pine forests are at risk due to shifting fire regimes and increased anthropogenic disturbance. Understanding how Flammulated Owls use old-growth forests can help us predict how changes in forest composition may impact Flammulated Owl communities. Flammulated Owl habitat selection has been well documented regarding their nocturnal foraging and nesting behaviors, but less is known about how they select day-roosting habitat. I sought to address this gap in knowledge by compiling data on the traits of day-roost sites selected by radio-tagged male Flammulated Owls in the 1980s and 2020s. I examined patterns in roost habitat use across three spatial scales: (1) the stand of trees in which roosts were located, (2) the roost tree proper, and (3) the perch the owl selected. I then assessed habitat selections by comparing roost sites to available but unused sites. Understanding characteristics of day-roosting habitat can help us predict how the loss of old-growth forests in the American West may impact Flammulated Owl habitat selection, influencing conservation and management strategies for the species. My results suggest that at each spatial scale, Flammulated Owls primarily selected traits that maximized the amount of foliage cover surrounding the roost. Additionally, results suggest that while Flammulated Owls rely on ponderosa pines and Douglas firs for day-roosting, they may rely more heavily on mature rather than old-growth trees.