NEST-SITE SELECTION AND REPRODUCTIVE SUCCESS OF CALIFORNIA-SPOTTED OWLS

We evaluated quality of nesting habitat and nest-site selection of an insular population of California Spotted Owls (Strix occidentalis occi dentalis). We assessed habitat structure for successful and unsuccessf ul nests from 103 independent territories at three spatial scales, and habitat selection by comparing nest stand structure with identical va riables from random points. Fledging success was unrelated to nest typ e, nest tree, nest stand characteristics, or habitat type. However, ne st productivity was greatest in lower elevation oak/big-cone fir habit at (1.7 fledglings per successful nest). Nest stands were characterize d by greater variation in tree size, higher canopy closure, and greate r basal area of large trees compared with random points. We were able to differentiate consistently between nest and random points using dis criminant function models (approximate to 79% correct classification), Our results confirm previous observations that California Spotted Owl s will use a variety of habitats, but these habitats are consistently characterized by greater structural complexity compared with available habitat.