Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Movement and distribution of confined and freely growing populations of cotton rats (Sigmodon hispidus)

Technical Report ·
OSTI ID:6511567

Three areas were chosen to study movement and spacing patterns of cotton rats (Sigmodon hispidus). The areas were: (1) a 2.4 ha natural area (Peach Orchard); (2) a 0.65 ha circular enclosure (Circular Pen); (3) a 1.13 ha double-sided enclosure (Double Pen). Vegetation density and species composition at each position were sampled at bimonthly intervals in all 3 areas. Weather conditions were continuously recorded by a local weather station. Computer simulation was used to examine biases in sampling methods and to determine optimal methods of analyzing results. Trap spacing was found to be important for cotton rats because they have small home ranges. Calculation of home range area based on the determinant of the variance-covariance matrix of capture points was best under a large variety of conditions. Cotton rats were most frequently captured in areas of dense vegetation. Males moved farther and had larger home ranges than did females during all seasons. Shifts in movements and spacing through the seasons were most closely related to vegetation changes, except in the spring. A shift of diet, commencement of reproduction, low levels of lipid reserves, and low population density all occur at this time of the year. Movements and area of home range were not related to population density indicating that density effects are not important factors in cotton rat activity. Rather the direct effect and interactions of vegetation, weather, interspecific competition, and predation are thought to be the principal factors affecting cotton rat movements and distribution.

Research Organization:
North Carolina State Univ., Raleigh (USA)
DOE Contract Number:
EY-76-C-05-0033
OSTI ID:
6511567
Report Number(s):
TID-290-19
Country of Publication:
United States
Language:
English