This is from my Elk Addict's Manual
Chapter 2: Elk Biology & Behavior
The more you know about elk biology and behavior, the better you should be at understanding why and when the elk are most active. The more you understand what type of habitat and forage elk use, and how and when they use it, the more you will be able to understand where to find them when you hunt.
In the winter, spring and summer elk often group together with the cows and calves in one herd, the older bulls in another herd and the younger bulls in still another herd, although young and old bulls may be found together, and yearling bulls may be found with the cow herds. During the spring and summer cow elk travel in large herds with their calves. These herds are often made up of an older dominant cow, her sisters, their daughters and their daughter's daughters etc. Research on European red deer shows that young females often follow their mothers to their summer grounds for up to three years, and that they often return to their mother's summer area even after that. Young males often follow their mothers to the summer ground for only two years, and then often "pioneer" or seek out new areas for summer ranges. The older bulls often remain apart from the cows until the beginning of the rut in late August/early September, and stay with them until November. However, I have seen bulls with cows as early as July. After the rut the bulls generally form loose groups and go off by themselves. Elk of both sexes and all ages may be found together in the winter, especially when food sources are limited.
Elk are grazing animals; therefore they are primarily a species of plains, open forest and semi-open forested mountains. However, they are very adaptable and thrive in the sparsely forested areas of the badlands of the Dakota's, and the semi-desert areas of New Mexico, Arizona and Oregon. In Minnesota and Michigan elk inhabit mixed hardwood and softwood forests near agricultural lands in the proximity of humans. In mountainous regions elk utilize open coniferous forests in foothills or mountains near creek and river drainages. These areas provide a mixture of different habitats with edges, where several forage species occur, and where there is fresh water for daily use. Research has shown that elk prefer to stay within 1/2 mile of free flowing water.
Preferred habitat for elk include drainages where evergreens meet aspen, alder, willow and shrubs, and where those species meet meadows or wetlands. Studies have show that the edges between two different types of habitat provide twice the number of species and amount of food than 50 yards into either habitat. As a result of this, elk use of the habitat declines after 100 yards into specific habitats. Habitats covering 30 to 80 acres satisfy the normal biological needs of elk for feeding or cover.
Elk prefer feeding areas from 20 to 45 acres in size, with from 0 to 25 percent cover and. In their daily movement elk routinely cross openings of 490 feet. However, when meadow or openings reach 985 feet, elk prefer to travel around rather than across the openings. Elk use open mountain top meadows adjoining forests on two or more mountains, because these meadows offer forage, cover, and access to different microclimates within a relatively small distance. The meadows provide the grasses, sedges and forbs (wild flowers/weeds) that elk prefer to feed on.
Slopes and Drainages
The angle of the slope has a noticeable effect on elk use in mountainous regions because of plant growth and microcline (temperature in specific areas). Elk use increases with the steepness of the slope to a maximum of 30 to 40 percent, with preferred slopes between 15 and 30 percent. There is a noticeable decline in elk use when slope angles exceed 40 percent. Upper slopes are preferred over middle and lower slopes in both the summer and winter.
River drainages and valleys are used extensively by elk in the summer because they provide thermal cover and late summer food, and they are often used as travel lanes. Northeast slopes are heavily used in summer and early fall because they retain moisture and provide succulent forage for the animals. South facing slopes are used twice as heavily in winter as north facing slopes, probably because of solar radiation, which causes snow melt and exposes available forage. The steep, rugged terrain of mountain slopes provide the elk with escape routes and succulent forage in late summer.
Coniferous Forest; Thermal and Security Cover, Bedding Sites
Coniferous forests offer escape and security cover for elk by providing protection from heat through shade, protection from the cold by retaining heat, protection from the wind and wind-chill factors by reducing wind speed by 50-70 percent, and protection from precipitation. The preferred coniferous forest for thermal cover (shade in the summer, wind protection in fall and winter) is ponderosa pine/Douglas fir or other mixed conifer types. For thermal cover to be effective it needs to be 30 acres or more in size in order to reduce wind speeds. Ponderosa pines 40 feet or more in height, without lower limbs, surrounded by sparse ground cover, are used in hot weather, because they provide shade for the animals while permitting cooling breezes to blow through the trees.
When security cover is used for hiding, the forest overstory is usually of moderate height with downed woody material and abundant browse on the ground, with approximately 200 trees per acre; preferred security cover is 600 feet wide. This same type of cover is used by elk in cold weather to reduce heat loss. Elk use of security cover declines between 450 and 600 feet into the cover; and elk rarely go deeper into heavy cover than 600 feet. When the avoid danger elk move an average of 375 feet into cover before feeling secure.
Preferred bedding cover for elk is often 75 to 100 percent closed, and 30 to 60 acres in size. During warm periods elk day beds are often found on north facing slopes; night beds are often found on south facing slopes, often in open areas. During cold periods day beds can be found on south facing slopes; night beds are usually on the downwind side of slopes. Most bedding sites are found near timber clumps, with the exception of warm weather night beds, that are often in open areas.
A study of Roosevelt Elk showed that from June through August their forage consisted of approximately 20 percent forbs (wild flowers/weeds), 20 percent browse and 60 percent grasses and sedges. Their diet changed from September through November, when 20 percent was browse, and 75 percent was grasses and sedges. This change can be attributed to the lack of succulent forbs later in the year.
Preferred forbs of Rocky Mountain elk during the fall include Common commandra, slimpod shootingstar, American licorice, dotted grayfeather, alfalfa, yellow sweetclover, mountain bluebells, cord-leaved montia, Siberian montia, alpine forget-me-not, Wilcox pentsemon, Columbian goundsel, Sitka valerian, wyethia and Common beargrass. Preferred fall grasses and grass like plants include bluestem wheatgrass, bearded bluebunch wheatgrass, blue wildrye, Idaho fescue, sheep fescue, Pary rush, millet woodrush, Timothy, bluegrass, and needle-and-thread. Preferred fall trees and shrubs include curlleaf mountain mahogany, quaking aspen, bitter cherry, Antelope bitterbrush, prickly rose, willow, blueberry elder, blackbead elder and American mountain ash. Elk are opportunistic feeders and relish the upper boughs and needles of freshly fallen spruce and pine, the bark of freshly fallen aspen, and acorns where available. They eat between 1.7 and 2.9 pounds of dry meadow grass per hundred pounds of body weight; large bulls may eat from 12 to 18 pounds a day.
Bull elk and cow elk often use differing amounts of the same food sources. In one study bulls used 10 percent more grass and cows used 10 percent more Salmonberry in September than they did in August. During one study there was a marked difference in the amount of food intake between the bulls and cows in mid-November, after the rut. Overall cow intake declined from September to October, while bull intake was highest after the rut (late October through November). This was probably due to the fact that bulls need to put on fat after the rut to get them through the winter, and the cows eat less during the fall, because the calves have begun to forage more and drink less milk.
If you have questions - fire away.