Habitat Selection by Mexican Spotted Owls in Northern Arizona

We compared use of seven habitat types to availability of those types within the home ranges of eight radio-tagged Mexican Spotted Owls (Strix occidentalis lucida). When all habitat types were considered simultaneously, habitat use differed from habitat availability for each owl. Patterns of habitat use varied among individuals and with respect to activity. Owls generally foraged more than or as frequently as expected in virgin mixed-conifer and ponderosa pine (Pinus ponderosa) forests, and less than expected in managed forests. Owls roosted primarily in virgin mixed-conifer forests. We also compared habitat characteristics among foraging, roosting, and randomly available sites. Habitat characteristics differed sig- nificantly among plot types. Both roosting and foraging sites had more big logs, higher canopy closure, and greater densities and basal areas of both trees and snags than random sites. Roosting sites had greater canopy closure, more big logs, and greater densities of both trees and snags than foraging sites. Mature forests appear to be important to owls in this region, and different forest types may be used for different activities. Received 4 November