Spotted Owl Home Range and Habitat Use in Southern Oregon Coast Ranges

We radiotracked 9 adult spotted owls (Strix occidentalis) in the southern Oregon Coast Ranges for 6-12 months. Owls selected home ranges that emphasized old growth within the landscape. Minimum convex polygon home ranges of 4 pairs were 1,153-3,945 ha and contained 726-1,062 ha of old growth. The percentages of the home ranges in old growth were 25-73%. Home-range size expanded significantly (P < 0.05) with decreasing proportions of old growth (r = -0.83). The amount of old growth in the pair home ranges was less variable than was home-range size. Old growth was selected by the owls for foraging and roosting (P < 0.05); clearcuts and other nonforested areas were not used. Early to middle stages of forest development were used either less than or in proportion to their availability within the home ranges, even where old growth was scarce.