Between November 1963 and October 1965 the long distance movements of Bank voles and Wood mice within an almost isolated 26 ha deciduous woodlot were studied by live trapping at approximately monthly intervals. Dispersal was most marked in juvenile Bank voles where most of the males and about half the females under 13 g, when released and later recaptured, had dispersed.

Dispersal of juvenile Wood mice did not occur after September, before which time the evidence was sparse and inconclusive. It was estimated that about 6% of adult maleand 2% of adult female Bank voles dispersed. Little dispersal of adult Wood mice took place.

The term ‘transient’ is discussed. True transients in the “once-caught’ category are thought to be few. There was no evidence that the trappable population of either species included a significant number of non-resident individuals.