Daytime habitat selection by cottontails in central Pennsylvania

Information on behavioral responses of wildlife to habitat alterations is needed to allow restoration and maintenance of suitable habitats for a variety of vertebrate species. We studied the use by radiotagged eastern cottontail rabbits (Sylvilagus floridanus) of habitats within a terrestrial ecosystem scheduled to be used for disposing secondarily-treated effluent (domestic wastewater) in central Pennsylvania. Cottontails selected old-fields and shrublands for daytime use, but croplands were used when oats and corn matured during summer and fall: Aboveground bedding sites (forms) were associated with relatively dense cover, indicating that cottontails recognized variations in microhabitat within habitat types. Females frequently used underground burrows when air temperature was less than 0 C, whereas males seldom used burrows except when air temperature was less than -5 C during winter. Cottontails encountered a wide range of microclimates at forms. Air temperature, net radiation, and wind speed extremes were -7.1 to 38 C, -21 to 70 W/ m 2 , and 0.0 to 11.3 cm/sec. Air temperature, net radiation, and wind speed were greater at open sites than those at forms used by cottontails during each season. Cottontails selected micro-environments in which the insulating effect of dense cover may allow conservation of metabolic energy or reduction of heat loss. Provision of dense herbaceous and shrub cover is essential to management of cottontail habitat because it allows the animal to maintain a positive energy balance as well as avoid predators. Typically, cottontails occupied a form from sunrise to sunset. Thus, the structure of vegetation associated with forms may be a key indicator of suitable cottontail habitat. Shrub-woodland habitat appeared to be especially important to cottontails during late winter and early spring because of increased cover associated with early leaf-out of shrubs.