Diet and foraging behaviors Mule deer

mule deer foraging on late winter morning @ okanagan mountain provincial park

kufleld et al. (1973) analyzed 99 studies of mule deer diets , found 788 species of plants eaten mule deer, , mule deer diets vary depending on season, geographic region, year, , elevation. kufeld, et al. (1973) gave following data rocky mountain mule deer diets:

anthony & smith (1977) found diets of mule deer similar of whitetail deer in areas coexist. mule deer intermediate feeders rather pure browsers or grazers; predominantly browse, eat forb vegetation, small amounts of grass, , available, tree or shrub fruits such beans, pods, nuts (including acorns, , berries.

mule deer readily adapt agricultural products , landscape plantings. in sierra nevada range, mule deer depend on lichen bryoria fremontii winter food source.

the common plant species consumed mule deer are:

among trees , shrubs: artemisia tridentata (big sagebrush), cercocarpus ledifolius (curlleaf mountain mahogany), cercocarpus montanus (true mountain mahogany), cowania mexicana (mexican cliffrose), populus tremuloides (quaking aspen), purshia tridentata (antelope bitterbrush), quercus gambelii (gambel oak), , rhus trilobata (skunkbush sumac).
among forbs: achillea millefolium (western yarrow), antennaria sp. (pussytoes), artemisia frigida (fringed sagebrush), artemisia ludoviciana (louisiana sagewort), aster spp., astragalus sp. (milkvetch), balsamorhiza sagittata (arrowleaf balsamroot), cirsium sp. (thistle), erigeron spp. (fleabane), geranium sp., lactuca serriola (prickly lettuce), lupinus spp. (lupine), medicago sativa (alfalfa), penstemon spp., phlox spp., polygonum sp. (knotweed/smartweed), potentilla spp. (cinquefoil), taraxacum officinale (dandelion), tragopogon dubius (western salsify), trifolium sp. (clover), , vicia americana (american vetch).
among grasses , grasslike species: agropyron, elymus (wheatgrasses), elytrigia, pascopyrum sp. (wheatgrasses), pseudoroegneria spicatum (bluebunch wheatgrass), bromus tectorum (cheatgrass), carex spp. (sedge), festuca idahoensis (idaho fescue), poa fendleriana (muttongrass), poa pratensis (kentucky bluegrass), , other poa spp. (bluegrass).

mule deer have been known eat ricegrass, gramagrass, bromegrass, , needlegrass, antelope brush, bearberry, bitter cherry, bitterbrush, black oak, california buckeye, ceanothus, cedar, cliffrose, cottonwood, creek dogwood, creeping barberry, dogwood, douglas fir, elderberry, fendlera, goldeneye, holly-leaf buckthrorn, jack pine, knotweed, kohleria, manzanita, mesquite, oak, pine, rabbitbrush, ragweed, redberry, scrub oak, serviceberry (including pacific serviceberry), sierra juniper, silktassel, snowberry, stonecrop, sunflower, tesota, thimbleberry, turbinella oak, velvet elder, western chokecherry, wild cherry, , wild oats. available, mule deer eat variety of wild mushrooms, abundant in late summer , fall in southern rocky mountains; mushrooms provide moisture, protein, phosphorus, , potassium.

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humans engage in supplemental feeding efforts in severe winters in attempt avoid mule deer starvation. wildlife agencies discourage such efforts, may cause harm mule deer populations spreading disease (such tuberculosis , chronic wasting disease) when deer congregate feed; disrupting migratory patterns; , causing overpopulation of local mule deer populations , overbrowsing of shrubs , forbs. supplemental feeding efforts appropriate when conducted under limited circumstances, successful, feeding must begin in severe winter, before poor range conditions , severe weather cause malnourishment or starvation, , must continued until range conditions can support herd.

mule deer variably gregarious, large proportion of solitary individuals (35 64%) , small groups (groups ≤5 deer, 50 78%). reported mean group size measurements 3 5 , typical group size (i.e. crowding) seven.