Mule Deer in Lemhi County - Natural History

Fish and Game has been receiving numerous questions, complaints and comments regarding the number of deer in our community. Some residents are having problems with deer helping themselves to garden vegetables and ornamental plantings. Others enjoy seeing the deer and many residents are simply curious about why we seem to have so many deer in town. In order to help provide some answers, Fish and Game will be presenting a three part series in upcoming issues of the Recorder Hearld. This week's article will discuss the natural history of mule deer and provide background information on how these animals live their lives. Subsequent articles will address why deer seem to like our town as well as what can be done to resolve human-deer conflicts. The animal we call mule deer is actually made up of a group of closely related subspecies that are familiar to residents of the western United States. They have one of the broadest distributions of any antlered game animal in North America, ranging through the western half of the continent from northern Canada to central Mexico. The subspecies found in our area is the Rocky Mountain mule deer (Odocoileus hemionus hemionus). Like any animal, mule deer have a variety of characteristics that help identify them. Their enormous ears give these deer their name. Another name sometimes given to mule deer is "blacktailed" deer because of the short black-tipped tail. One subspecies, found along the Pacific coast from northern California to Alaska, is formally called black-tailed deer. Mule deer appear to be a stocky short-legged animal when compared to its lanky long-legged cousin the white-tailed deer. Adults range from 4.5 - 6 feet long and 3 - 3.5 feet tall at the shoulder. Bucks can weigh 125 - 275 pounds and have been know to tip the scales at 400 pounds. Does average 100 - 180 pounds. Other characteristics include a large white rump patch and dark forehead. Antlers have a distinctive growth pattern that is much different from that of white-tailed deer. Mule deer antlers branch equally into forked tines, which may again branch into more forked tines. White-tailed deer, on the other hand, have a main antler beam with single tines growing off this main beam. Even the mule deer's gait is distinctive. Called "stotting," this bouncing gait is caused when a deer bounds and lands on all four feet at once, giving the deer a pogo-stick appearance. Stotting is an advantage in steep areas where it allows rapid vertical ascent of hillsides in bounds of 9 -17 feet. In covering such a large geographic area, mule deer encounter and have adapted to a wide range of habitat types. Seven different ecoregions make up the western US and mule deer can be found in each of these. The Salmon region falls within the Northern Boreal Forest Ecoregion. Dominant tree species include pine, spruce and Douglas fir. Winters, as many of us know, can be long, snowy and cold. Because of this, many mule deer living within this ecoregion are migratory, moving up and down in elevation with the changing seasons. Mule deer summer range is a diverse mix of coniferous forest, meadows, aspen woodlands, and even alpine tundra. Food sources in the form of forest shrubs, saplings, forbs, and grasses are abundant. During winter, the deer are found in the foothills and valleys seeking out shrub/grass communities. If little snow falls, migratory mule deer may remain in higher elevations throughout the winter. Given their wide distribution, mule deer have access to a large variety of food plants. Researchers have documented nearly 800 different kinds of plants that mule deer eat. By far, forbs such as wildflowers make up the bulk of a mule deer's diet in most seasons. Twenty-five per cent of the diet is made up of shrubs and trees while grasses make up approximately 12 per cent. Familiar plants eaten by mule deer include snowberry, big sagebrush, rose, bitterbrush, buckwheat, lupine, phlox, yarrow, and beardtongue. Many of these plants are available only during the summer months, making them important to the endless quest of storing fat for winter. With the dual stresses of the autumn rut and winter over, bucks begin accumulating fat reserves in early spring. The does, however, are using most of the available food energy of summer raising fawns. Fawns are born in late May to early June and are initially dependent upon their mother's milk. Mule deer milk contains more fat, protein, ash and total solids than cow's milk making its nutritional value twice that of cow's milk. Healthy fawns exhibit a very rapid growth rate thanks to this excellent food source. Mule deer does generally have one fawn in their first and second years and twins thereafter. Triplets are rare and usually the offspring of a doe that is at least 4years old. At birth, mule deer fawns weigh approximately 8 pounds. They are nearly odorless and cryptically colored because of their spotted coat. Mule deer display what is known as the "hider" syndrome where fawns remain hidden away from their mother except for brief periods of nursing throughout the day. This behavior continues until the fawn is 6 - 8 weeks old and able to accompany its mother. As autumn approaches, does and fawns can be seen in small groups as they feed beginning at dusk and continuing until dawn. Daytime usually finds them bedded in sheltered areas where they rest. By this time, bucks have finished storing fat and are preparing for the rut. Does and fawns continue to store fat as long as quality food supplies are available into the autumn. While the quality and quantity of food supplies limit mule deer populations, weather, predation (including hunting), parasites, diseases, and human activities such as development, disturbance of winter range, and construction of migration barriers also impact mule deer. It would seem easy to point a finger at these impacts individually, but they rarely operate independently of one another. In the next article of this series, we will look at how weather and human activities act to bring deer into town.