Southern, William E.||Mathers, Carrol K.
M.S. (Master of Science)
Department of Biological Sciences
The environmental factors that affect the habitat preference of the cottontail rabbit (Sylvilagus floridanus) were studied during the summer and winter of 1967-1968, on a 15.2 acre section of the Charles Faivre farm in DeKalb County, Illinois. I attempted to analyze the habitats selected by cottontails for nests and dens, the microclimatic conditions associated with nests and dens, the dally activity cycles of rabbits in relation to habitat, and the environmental conditions affecting denning behavior. The types of vegetative cover surrounding nests and dens were recorded. I classified the 16 nests into three main categories: four (25.0%) were unused-abandoned; six (37.5%) were successful-abandoned; and six (37.5%) were active-ready. Eight nests were located in the grass-forb-shrub community and eight were in the young shrub-tree community. Ten (62.0%) of the cottontail nests were under small hawthorn trees. The rabbits used dens constructed by other animals. Of the 24 woodchuck dens I located in the study area, six (25.0%) were in the grass-forb-shrub community, ten (41.7%) were in the young shrub-tree community, and eight (33.3%) were in the old shrub-tree community. Temperature recordings were made in various nests and indicated that the nest materials and the ground provided an effective insulation against changing environmental temperatures. The daily temperature ranged from 2° to 6°F in an unoccupied nest, while the surrounding air temperature fluctuated aa average of 19°F per day. The buffer effect provided to cottontails by the underground dens against the outside air temperature was noted. The dally temperature fluctuation in a den averaged 2° to 3®F while the average ambient temperature fluctuation was 17° to 18®F per day. The microclimatic factors that possibly influenced the selection of nest and den sites were discussed. Variations in cottontail activity were analyzed in relation to temperature, wind velocity, and precipitation. Three peaks of activity were observed: (1) two hours surrounding sunset; (2) two hours surrounding sunrise; and, (3) 00 50 to 02 50 hours. Rabbit activity decreased during lower temperatures (10®F) and also decreased during periods of high wind velocities (15 mph or above). The possible needs of cottontails for shelter are listed, discussed, and compared with the results of other investigators. The major needs are: (1) protection from adverse weather; (2) protection from enemies; and, (3) inherent behavioral characteristics.
Bruckner, Wayne H., "The environmental factors affecting the habitat preference of the cottontail rabbit (sylvilagus floridanus)" (1968). Graduate Research Theses & Dissertations. 5735.
ix, 73 pages
Northern Illinois University
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