CDFW Wildlife Branch 1812 9th Street
Sacramento, CA 95811
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Elk are highly social animals, and the herd is the focal point of its existence (McCullough, 1969). Tule elk utilize various portions of their range in response to seasonal variations in food availability (Thomas and Toweill, 1982). McCullough (1969) states that these seasonal movements are not considered migrations; they are local shifts in response to local conditions. The areas used during the summer are not inaccessible because of weather during the winter and the movements are not consistent from herd to herd. He also suggests factors that influence the various movements of the herds. First is the availability of high quality forage. A second factor is the land use by domestic livestock. This factor is dependent on the availability of suitable habitat to which the elk can shift. The third factor is human interference. When disturbed, herds will shift from place to place granted there is suitable forage available. In areas where there is little or no disturbance, the movements become fixed.
Elk are a herding species but the extent of herding can vary by sex and time of year. In the spring the animals can be scattered and the cows can be alone or in small groups while they give birth (Murie, 1951). As soon as the calves are able to walk without too much trouble the cows will usually group back up and travel as a herd with groups ranging from 15-200 (Hobbs, 2007). These groups will usually consist of cows, calves, and young bulls (spikes). Bulls are usually found in smaller groups and many times the larger more mature bulls will be by themselves until the breeding season begins (McCullough, 1969).
The breeding season or rut for tule elk occurs later in the season in much warmer temperatures compared to other elk (Wormer, 1969). The rut usually occurs from August through October. The peak of the rut on Grizzly Island is usually late August to Mid September (Hobbs, 2007). Bugling is the most characteristic act of the bulls rutting behavior. Bugling is a call the bulls make to attract mates. As the rutting season progresses bulls begin to compete for cow herds.
The gestation period is 255 days with most young being born in May and June, but calves have been reported as early as February and March in some areas. Calving usually occurs away from the group in areas with cover such as tall grass or brushy areas and away from disturbance (Zeiner, Laudenslayer, Mayer, and White, 1990). Cows will become sexually mature around the age of two and the calves will usually remain with their mothers to become part of the cow herd (Hobbs, 2007).