Long-distance dispersal is an important phenomenon in both theoretical and applied population biology, yet empirical data are difficult to collect. We analyzed long-distance movement data for cotton rats (Sigmodon hispidus) and prairie voles (Microtus ochrogaster) for sex and seasonal biases by use of Fisher's exact tests, and the effects of density and potential competitors on movement by use of logistic regressions. These data consisted of marked arrivals to an area used for a long-term, capture-recapture study of small mammals. The immigrants arrived from other study plots in the vicinity and from patches of habitat trapped during a long-term investigation of patch dynamics. In cotton rats, but not prairie voles, long-distance movements were male biased and dominated by subadults. In cotton rats there was a marginal statistically significant seasonal difference between the relative proportion of immigrants and the population where they arrived (target population). Immigrants in the autumn composed a higher proportion of the target population than in other seasons. In prairie voles immigrants were a higher proportion of the target population in the summer and autumn than other seasons. There was no evidence that either abundance of conspecifics or other species influenced long-distance movements.