Matriarchy—Family groups include an adult female, her fawns, and female young from the previous year.
Larger herds are usually comprised of multiple family groups.
Social groups led by a dominant female tend to stay in higher quality habitats.
Some groups may have younger males join temporarily during the summer.
Males may form small bachelor herds during the spring-summer, associating with females during the breeding season.
While dominant males do most of the breeding with females, yearlings and subordinate males may breed as well.
Male and female deer and all age groups tend to congregate during the winter, particularly in northern climates.
Home range—The area that an animal uses to meet the majority of its needs including feeding, resting, shelter, escape from predators, and mating.
Home range size varies greatly depending on factors such as food availability, cover, and mortality risks.
Sex differences—Males tend to have larger home ranges than females.
Beyond the range—The distances traveled by some deer during mating may take them outside of their normal home ranges. This is also true if they are motivated by the lack of food or driven by hunters or dogs.
reasons to move
Deer move in response to social interactions, food availability, predators, human activities, and weather. They may travel long distances in search of a place to give birth.
Crepuscular—mostly active between dusk and dawn.
Dispersal—typically a one-way movement from the birth area to a new home range.
In one study, 28 miles was the average one-way distance females traveled to a new home range. They used nearly straight lines crossing roads, rivers, and power line rights-of-way.
Dispersing can put deer at risk of vehicle collisions. They also often find themselves in competition for food, cover, or mates.
Sex differences—More males (65%) dispersed than females (39%) in central and northern Illinois.
Migration—A two-way movement in response to variability in a needed resource such as cover or food.
Sex differences—In Illinois, females may move between summer and winter ranges, but among 282 males studied in central and northern Illinois, no migration behavior was observed.