Movement Patterns of Field Rodents in Hawaii

The setting for a 10-year study of the ecology of the plague organism is described. Four rodents, Mus musculas, Rattus exulans, R. rattus and R. norvegicus, were investigated during 1959-64 by the mark-and-release method, with numerous grids and lines of traps set in coastal fields of sugar cane and in adjacent uncultivated lands, primarily rugged gulches. Fluctuations in population densities are related to season, to cultural practices for sugar cane, and to the movement and home range of rodents. Harvest of the cane is a catastrophe for rodent populations in the fields, and few that escape to adjacent lands survive to become established there. Patterns of movement are remarkably similar in the four species, but gradients toward longer movements follow trends for greater body size. Significant differences in distances moved are derived between species and between sexes within species, in time and in different habitats. Home range and local movement of the field rodents of Hawaii have many parallels with those of the same species as reported in other regions of the world and in other cultural surroundings, but direct comparisons are seldom possible because of differences in methods used and in environmental conditions