Forage-area separation and overlap of four species of seed-eating desert rodents were measured by placing seed dyed four colors in four microhabitats and allowing the rodents to forage and ingest the seed. The four microhabitats delineated were as follows: (1) areas lacking vegetation; (2) areas containing small scattered bushes .5 m tall and .5 m across; (3) areas containing clumped bushes .1 m across and 1 m tall; (4) areas containing large bushes greater than 1 m tall and 1 m across. Rodents were live-trapped and their feces collected and analyzed for color, which would indicate the forage area of each species. Results of these experiments demonstrated that Dipodomys merriami foraged in areas lacking vegetation, Perognathus amplus among scattered and clumped vegetation, P. baileyi among clumped vegetation and large bushes, and P. penicillatus under large bushes. A population of D. merriami was perturbed and P. amplus significantly shifted its forage pattern to the open microhabitat. Thus, Dipodomys affected habitat selected by P. amplus. Preliminary analysis of captures of heteromyids on sandy or gravelly substrate indicated that P. baileyi prefers gravelly soils and may exclude D. merriami from this substrate. Habitat selection was found to be an important factor in the coexistence of these species, with interspecific interactions partially influencing the habitat these species selected.