Status of the Spotted Owl, Strix occidentalis, and Barred Owl. S. varia, in southwestern British Columbia

Abstract

Calling surveys were used to assess the relative abundance and distribution of Spotted and Barred owls in southwestern British Columbia from 1985 to 1988.Spotted Owls were located at 14 sites, including pairs at 7 sites and single birds at 7 sites.One Spotted Owl nest was located.Barred Owls were located at 57 sites, including pairs at 14 sites and single birds at 43 sites.The average number of individuals responding per km of survey transect was 0.04 and 0.15 for Spotted and Barred Owls, respectively.The low response rate for Spotted Owls indicates that the species is rare in British Columbia.We estimated the population at not more than 100 pairs.Although the Spotted Owl has probably never been abundant in British Columbia, we hypothesize that the population has declined because of habitat loss and displacement by the Barred Owl.