The traps were operated eight to twelve days and closed for two to five days intermittently throughout the trapping period except in the months of April to August, 1955, when trapping was unsuccessful because the cottontails then were not attracted by bait.
Two kinds of traps were used in my study: those made by the National Live Trap Company and those described by Fitch (1950). Both types performed well and were serviceable under ordinary field conditions. Experiments were made periodically throughout the trapping period to determine which bait was most attractive to cottontails and least attractive to birds, rodents, skunks, raccoons, and opossums. All of these animals hindered operations by stealing bait and springing traps. Corn, scratch-feed, carrots, parsnips, tomatoes, lettuce, apple, cabbage, raisins, sorghum, sugar candy, and onions were used as bait. Corn and scratch-feed attracted cottontails best in all seasons. Corn was superior to scratch-feed, which was quickly stolen by small birds and rodents. Eighty-nine cottontails (40 females, 49 males) were captured in the course of the study.
Cottontails were marked individually at the time of first capture. When necessary, the markings were renewed at later captures; in all such instances the same color codes and numbers were retained for each. Markings were of four types: numbered ear tags, colored ear ribbons, colored tail fur, and colored feet. It was intended to make each individual cottontail recognizable in a trap or in the field. Occasionally when a predator had killed and eaten a cottontail the tail and feet remained and, when dyed, they provided important clues to the identity of the individual. However, the color of the feet is not ordinarily discernible in the field while the rabbit is alive.
Monel metal ear tags (size No. 4, National Band and Tag Co.) were punched through the lateral or posterior fold of the ear close to its base (Pl. 48), one in each ear as insurance against possible losses. However, only three tags were pulled out of the ears and lost in the course of this study. In no instance was identity of an individual cottontail lost. The tags caused no damage to the ears over a period of 21 months.
Trailing in snow is an effective method of studying the daily activities. The record preserved by the tracks becomes somewhat confused after the snow has lain on the ground for more than one night, and after the third night it is impossible to read the surface of the snow. The first day of thaw usually ends tracking because the investigator loses the trail when it crosses a patch of bare ground. The use of a dye on the feet of the individual to be trailed eliminates much of the difficulty of determining which tracks are to be followed. One or more feet can be dyed when the investigator handles the animal in releasing it from the trap. The trail of dyed footprints is distinguishable from all other rabbit tracks in the area. Even when only patches of snow remain, the animal can be followed by checking the edges of the snow for the emerging footprints of the marked rabbit. The same dye is used to color the tails. The color persists in the footprints for about three hours, over a distance of 600 to 800 yards. The animal leaves only a small spot in each footprint, but when it pauses, the mark is large. Red dye makes the most conspicuous mark in the snow.
Thirty-one rabbits were trailed 68 times with one to six records for different individuals. Almost two-thirds of the trailing records pertain to males, which were caught more easily than females while snow was on the ground.
The trail, for both sexes, in those individuals released and followed immediately was longer than in individuals released and allowed to move away before they were followed. The area ranged over by a trailed individual was not significantly greater in either case. The area ranged over was greater by day than by night. Individuals continued to move while being followed in the day, but stopped to forage and look about at night.
Records were obtained by identifying cottontails that I flushed from forms as I walked through the study area, sometimes using a noise-making device or dragging a rope. Regular search was made along the hilltop rock outcrops, under which hiding cottontails could be identified with the aid of a flashlight. Forms in brush piles, and thickets were visited and the inhabitants identified. Other persons, working on the study area, supplied some of the records of cottontails that were seen alive or found dead. Also through binoculars or a telescope I watched movements of undisturbed individuals. Twenty-three individuals were identified 59 times. Nine females were seen 28 times and 14 males were seen 31 times. Sixty-five other individuals were seen, but could not be identified in the field.
MOTIVATION AND EXTENT OF MOVEMENTS
The home range is an area in which an animal carries on its normal activities of eating, resting, mating, caring for young, and escaping from predators. The cottontail establishes a definite home range and may live its entire life within this area, which permits familiarity with food sources, hiding places, and escape routes.