Abstract The study of the substructure of small mammal populations has contributed to many foundational concepts in population biology. The contemporary model, summarized in Anderson’s Resident Fitness Hypothesis, posits that resident small mammals have site tenacity, behaviorally resist intruders, and female offspring tend to be philopatric but young males leave their natal area. To evaluate this model, we analyzed 3 long-term data sets for 3 rodent species from 3 US states, totaling 34,536 animals across 40+ yr of study. The expectation of site tenacity with fixed home ranges was not supported because the majority of rodents (53.9%) were trapped only during a single month, and only 21.8% were caught 1 mo later. Similarly, the expectation that residents resist intruders was unsupported because 60.5% of initial captures were adults. Multiple logistic regression revealed that females had increased predicted probability of recapture for all species, and, for both vole species, the predicted probability of recapture increased with each gram of body mass at initial capture. These results provide little support for the expectation of offspring persistence near natal areas. Taken together, the resident fitness hypothesis is not well supported in these populations of grassland rodents. Movements of some other vertebrate populations, in association with food abundance, have been modelled in Lévy flights and Brownian motion. It is possible that movement patterns of rodents in these 6 populations derive from 1 or a combination of these strategies.
Rice et al. (Sat,) studied this question.