Relatively little is known about how many mule deer inhabited the west before the arrival of the early pioneers. Trappers and explorers rarely reported seeing deer. Although Father Escalante’s journal reports it was necessary to kill some of his party’s horses, buffalo, and bighorn to survive; no mention was ever made of deer.
A few years later William Clark reported shooting a “curious kind of deer of a dark gray colour” along the Missouri River near the mouth of the Niobrara River. Meriwether Lewis wrote that the ears and tail of this animal were mule-like. This description was confirmed years later when the species was formally named “Odocoileus hemionus”- meaning half-mule. When Lewis and Clark reached the lower Columbia River they observed another form of “black-tailed” deer. Again this deer was described as being half common deer and half mule.
Today, mule deer collectively are one of the most widely distributed of all species of large mammals native to western North America. This “blue-collar” deer may also be one of the most economically and socially important animals in western North American culture.
Pre-settlement populations of mule deer have been estimated to exceed 10 million. Blacktails may have numbered over 3 million. Others suggest that the combined populations never exceeded 5 million. Thus, the debate about how many mule deer actually inhabit the west is not new.
Early explorers and settlers reported finding deer scare throughout the west. This scarcity is often attributed to a low value habitat. Many of the western rangelands during this period were dominated by grasses and other vegetation that had little value for mule deer. Most western states reported that after settlement, existing mule deer populations declined dramatically due to unrestricted hunting. The animals were heavily hunted for subsistence. By the early 1900s, mule deer were scarce.
It is ironic, that the very post-settlement activities many people today associate with environmental degradation – livestock grazing, logging, and burning – brought mule deer back from the brink. These activities created a near western landscape that contained more diverse range and forest vegetation which deer found tasty and nutritious. Additionally predators were widely controlled, there was little competition from other big game animals, hunting was restricted, and game enforcement became more effective.
By the 1920’s mule deer were again abundant in many parts of the southwest. By the 1930’s they had spread north and west occupying most available habitats. Although reliable population estimates are lacking, it is likely that by the 1960’s there may have been more than 7 million mule and black-tailed deer roaming the West. By the mid 1980’s populations were declined in many areas with numbers estimated to be around 5 million. This trends appears to be continuing in many parts of western North America (Figure 1).
No reliable estimate of historic mule or black-tailed numbers exists for any state or province. The estimates available are compilations of data collected by various methods. These methods may include aerial or ground counts, herd composition counts, pellet counts, and harvest records.
Because declining harvests have often accompanied by more restrictive hunting regulations, some might argue that reduced harvests simply reflect reduced hunting opportunity and not declining herds. Although many of the western states that report declining mule deer populations have also experienced reduced license sales, the declines in the number of deer harvested far exceeded the lost tag sales. Thus, for the west as a whole, the decline in deer harvest far exceeds that which can be solely explained by declining tags sales (Figure 2).
If the available records are taken at face value, the only possible conclusion is that mule deer populations are declining range wide, but given the paucity of historic records, we may never know the magnitude.
Causes of the deer decline
Rocky Mountain mule deer are one of the most adaptable and widespread ungulates. Mule deer have provided more than 3 million hunters in 11 western states as well as millions of wildlife viewers’ incalculable pleasures. Unfortunately, mule deer populations in the western U.S. are declining. The effects of these declines go beyond deer, the hunter, and wildlife viewer, because they invariably result in reduced income for state wildlife agencies and affect local economies.
Continued habitat loss and deterioration, habitat competition, severe winter weather conditions, deer-vehicle collisions, predation, disease, poaching, and increased hunting mortality have frequently been cited as factors contributing to this decline. Wildlife managers however, ultimately believe the key to sustaining abundant populations of mule deer and other big game animals over the long-term lies in maintaining the habitat base. Increased human habitation of rural areas, subdivisions and other developments on important winter range and conservation of preferred summer and winter range vegetation to less palatable and nutritious forages is seriously eroding mule deer habitat.
As pressures on mule deer and their habitat increase private landowners and public wildlife managers will need to become more adaptive in their management approaches. If mule deer are to recover, population and habitat management must become a priority. In some places, increasing populations of other wild animals in traditional mule deer habitats have taken management priority away from mule deer. Difficult decisions will have to be made about mule deer as compared to these other species.
To address these multitudes of issues, the Western Association of Fish and Wildlife Agencies has formed the Mule Deer Working Group. This group, composed of representatives of all the western mule deer sates and provinces, is working collectively to chart a region wide mule deer recovery plan.