Females incubate eggs and brood young while males bring food to the nest. The Western Screech Owl is single brooded, but may re-nest if first clutch is lost. Pairs will often reuse nest sites in consecutive years. Pairs mate for life but will accept a new mate if the previous mate is lost. Grey and red colour phases will mate together.
Adults tend to remain near their breeding areas year-round while juveniles disperse in the autumn.
Small territories around nest sites are vigorously defended by males. Cannibalism by other Screech Owls also occurs. Western Screech Owls are dependent on deciduous woodlands or open mixed forests that have suitable nesting sites and sufficient prey densities. Removal of riparian forest in drier regions will cause population declines because most densities are highest in riparian zones. However, this adaptable Owl can survive in wooded suburban areas and city parks as long as long as they are not directly persecuted.