A 2-year capture-mark-recapture study was conducted to estimate home ranges and weekly travel distance of Mastomys natalensis (Smith 1834) in irrigated rice ecosystem and fallow fields.We found that adults have larger home ranges than subadults in fallow fields but not in rice fields,indicating that fallow fields are more suitable for breeding.Travel distances were larger in rice fields,especially in the transplanting stage,during which rice fields are flooded and provide less food,causing movements into neighbouring fallow fields that then temporarily experience higher population density.A decrease in travel distance was observed in rice fields during the maturing stages,which can be explained by higher food availability and a more suitable,non-flooded situation.Movement of M.natalensis in rice-fallow mosaic landscapes thus seem to be driven by food availability and flooding status of the rice fields.This can be a focus for pest management by applying poison in a band around the rice fields,and preferably taking into account the rice growth stages.