This study measures the magnitude of the competition between two nocturnal, desert rodents, Dipodomys ordii and D. merriami, on 10 unenclosed, 16 hectare plots along a narrow band of sympatry in south-central New Mexico. Population perturbations of one or the other species were periodically performed on eight of the plots, while natural population changes were monitored on two controls. The relative numerical responses of the kangaroo rats to these perturbations are thought to reflect the true magnitude of their competitive interaction
