INTER-ISLAND MOVEMENTS OF RICE RATS (ORYZOMYS PALUSTRIS)

We hypothesized that the ability of the semiaquatic rice rat (Oryzomys palustris) to colonize over water is responsible for its ubiquity on the frequently overwashed Virginia barrier islands. A mark and recaptu re program was conducted from 20 May to 24 August 1989 on three adjace nt islands to determine the frequency, direction and causes of the mov ements. During this study, 11 of 166 island residents migrated for the duration of the study to other islands. All recorded crossings were m ade from a small island to larger islands. The demographic composition of the overwater dispersers was a statistically random sample with re spect to age and sex from the resident population, unlike rice rat ove rland dispersers that were predominantly juveniles.