PARENT SESSION

Behavior 1 -- Session Chair: Eileen Lacey-- Nelson Hall East, Goodwin Forum

SPACE USE AND SOCIAL ORGANIZATION OF ENDANGERED MT. GRAHAM RED SQUIRRELS: IT'S LONELY AT THE TOP. John L. Koprowski and Sarah R. King. Wildlife and Fisheries Science, School of Natural Resources, University of Arizona, Tucson, AZ, USA.

ABSTRACT- The Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis) is endemic to the high elevation coniferous forests of a single montane isolate in southeastern Arizona; the species was listed as endangered in 1987. A dearth of ecological data on the species has been promulgated due to extreme difficulty in capturing this rare tree squirrel. A number of basic ecological questions have remained unanswered including such important questions as the amount of space used by a single individual and interindividual overlap. In 2002, we initiated a radiotelemetric study to investigate the behavioral ecology of Mt. Graham red squirrels. Herein, we review home range sizes, maximum linear movements, interindividual overlap, and communal nesting of more than 40 individuals during the first year of space use studies. Home ranges are large in comparison with other populations but are characterized by a small core of intensive use. Few differences were found between the sexes; however, long-distance movements were occasionally made by males, apparently associated with the breeding season. Although often described as territorial and solitary, Mt. Graham red squirrels demonstrate some spatial overlap with rare instances of nesting in pairs. These results have important implications for informed conservation and habitat management decisions of this endangered species.

KEY WORDS: conservation, Tamiasciurus hudsonicus, sex differences