An Investigation of Competition in Natural Populations of Mice
Larry D. Caldwell
No evidence of aggressive competition (fighting, etc.) was obtained by Mus was definitely at a disadvantage in competition for food when population density was high or when the 2 species were confined in the enclosure. It is postulated that the migratory behavior of Mus is a mechanism which reduces competition between it and the more sedentary Peromyscus enabling both species to coexist in the same habitat even when Mus appears to be less well adapted to the Upper Coastal Plain environment.
SREL Reprint #0047
Caldwell, L.D. 1964. An investigation of competition in natural populations of mice. Journal of Mammalogy 45:12-30.