SPATIAL-ORGANIZATION OF THE ISLAND FOX (UROCYON LITTORALIS) ON SANTA-CRUZ ISLAND, CALIFORNIA

We measured size and overlap of home ranges and core areas to evaluate the spatial organization of island foxes on Santa Cruz Island, Califo rnia. Home ranges and core areas did not differ significantly between study areas, genders, or the wet and dry season. Consistent with islan d vertebrates elsewhere, home ranges of island foxes were considerably smaller than those of gray foxes, their closest relatives. The social organization of island foxes, however, was similar to that of gray fo xes and primarily consisted of male-female pairs occupying home ranges with core areas that overlapped little with those of adjacent pairs. Substantial spatial overlap between pair members, lack of intersexual differences in size of home range, slight physical dimorphism, and equ al sex ratios suggest that island foxes may be monogamous.