The cottontail usually establishes its home range in the area where it was born, being semi-gregarious and tolerant of crowding. Eight cottontails that were captured and marked as young remained in the area of original capture after becoming adults. Two of them lived 17 months in the same area, two lived 14 months, two lived 13 months, one lived 12 months and one lived eight months. No young were observed to have moved to another home range after they matured, although some may have moved off the study area and thereby escaped observation.
Young become independent and are seen foraging and moving about by the time they weigh 200 to 300 grams, at an age of four to six weeks. They associate with other young of the same litter and neighboring litters, and frequently frolic together. When two to three months old and weighing 400 to 700 grams they begin to live a more solitary life and usually rest alone in forms. Fourteen young between one and six weeks of age never were recorded to have moved more than 150 feet.
The population reaches its peak in August or September; home ranges varying in size from one-half acre (in young ranging in size from 150 grams to 800 grams) to 12 acres, in adults, are superimposed upon each other. In a woodland area of approximately 21 acres 33 cottontails were living together in September, 1955.
As the growing season ends and winter approaches, the amount of food available to the cottontail decreases and the cover becomes sparser (Pls. 45 and 46); predators, disease, and weather take their toll of the young. The survivors must move farther to find adequate food and cover. The home range of the cottontail in the first winter is overlapped by the home ranges of the other members of the same litter, and members of other litters, as the home range is enlarged to approximately its full size. By April the population reached its annual low point; nine of the original 33 cottontails were known to have survived on the 21-acre area of northwest-facing wooded slope south of the pond.
Foremost among the needs of the cottontail are food and cover. Daily movements motivated by these needs are the most frequent and most extensive that it makes. Movements such as are associated with courting and mating, escaping severe weather, escaping from predators, and caring for young are seasonal or irregular in occurrence.
Because the abundant vegetation of summer provides adequate food and cover, movements made while foraging and seeking concealment are less extensive than those made in winter when leafy vegetation is absent and food is scarce. The average length of trails of foraging cottontails was 175 feet per day in summer (11 individuals observed without disturbance) and 325 feet per day in winter (22 individuals trailed or observed without disturbance).
In the spring and summer cottontails forage mostly near woodland edges for grass and herbs, and usually wander no more than 40 feet into the grasslands from the protection of woodland edges and thickets. In autumn and winter cottontails forage in woods and along woodland edges for bark of trees and shrubs and for fallen fruits of trees. Ninety-two per cent of all fecal pellets found in grassland were within 40 feet of cover suitable for cottontails.
Movements made by the cottontail while foraging appear aimless; typical behavior consists of progression with a hesitant gait of two or three hops, a stop to eat, another series of hops and another stop. Footprints made by this movement are about 12 inches apart. With occasional spurts of hopping the individual moves perhaps ten to twelve feet where it stops and begins to eat again. The area in which the individual forages is usually elongated with its long axis parallel to the edge except in areas of uniform habitat (such as large patches of coralberry) where the area covered tends to be more nearly circular. Cottontails observed foraging were estimated to utilize 10 to 20 per cent of the home range area in one evening. Paths or runways are not ordinarily utilized by foraging cottontails.
In seeking protection from predators or from the weather, cottontails move farther in winter than in summer. The average length of trails of cottontails flushed by me in the study area was 80 feet in summer and 210 feet in winter.
When cottontails were released from live-traps they ran an average of 30 feet before stopping to look about. Cottontails always ran toward the densest cover within 50 feet of the point of release. Ten per cent of the cottontails released from live-traps did not stop running until out of sight (always more than 30 feet).