DISPERSAL MOVEMENTS AND SURVIVAL RATES OF JUVENILE MEXICAN SPOTTED OWLS IN NORTHERN ARIZONA

We monitored dispersal movements of 19 radiotagged juvenile Mexican Sp otted Owls (Strix occidentalis lucida) in northern Arizona during 1994 and 1995. All juveniles initiated dispersal movements in September or October during both years, with most dispersing during September. Ini tial dispersal movements were rapid and abrupt, but lacked a significa nt directional pattern. Distance from the nest to the last observed lo cation and the most distant location reached ranged from 0.6-72.1 and 2.1-73.5 km for individual owls, respectively. These distances represe nt minimum estimates of dispersal capability because only one individu al was tracked until it settled on a territory and paired. Owls used a variety of habitat types during dispersal, some of which differed mar kedly from typical nesting habitat for Mexican Spotted Owls. Four of f ive owls that were tracked past mid-November moved to lower elevation pinyon-juniper woodlands and at least one overwintered in pinyon-junip er woodland. Kaplan-Meier estimates of annual survival rate ranged fro m 20.5-28.7%, depending on whether we censored all owls with unknown f ates or included suspected deaths as mortality events. Estimates diffe red significantly between years and confidence intervals were wide, su ggesting that longer-term studies of large numbers of owls will be req uired to obtain accurate and precise estimates of juvenile survival.