Philopatry, Dispersal, and Habitat Saturation in the Banner‐Tailed Kanagaroo Rat, Dipodomys Spectabilis

We report natal dispersal distances for 331 banner—tailed kangaroo rats (Dipodomys spectabilis) at high and low population density. The data were collected in 29 censuses of marked individuals in two populations over 8 yr. One population underwent four—fold variation in density. The other was consistently at high density. Because the number of burrow systems (i.e., breeding sites) remained fairly constant, we interpret changes in density as changes in degree of habitat saturation. Dispersal distances were shorter and the proportion of philopatric young (moving less than a home range diameter) was greater at high density than at low density. This result does not conform to models of dispersal based on studies of cycling small mammals or to a simple competition model of dispersal. All data are consistent with a habitat saturation model, which holds that high—density saturated conditions favor philopatric tendencies in offspring.