The temperatures drop. Snow falls across the landscape and the deer must respond. Winter is here, making survival—simply staying alive—the main job for wildlife. Deer have different strategies for dealing with this population-limiting time of the year depending on the species and region where they live.
Some mule deer migrate out of mountain summer-fall range to lower, warmer areas where there is much less snowpack than where they spent the time of summer plenty. This is common in Eastern Washington, particularly along the east slope of the Cascades and the Blue Mountains. They often seek out south-facing slopes to take advantage of winter sunlight, less snow, and more exposed shrubs for foraging.
Whitetails, and similarly black-tailed deer, tend to live in dense, brushy habitats. Only in some situations do they migrate in winter, moving down in elevation in late fall and seeking out wintering habitats where snow is somewhat lessened, and they are left alone. Resident animals will mix with the migrants of all species and sometimes share winter territories.
This is the best season for cougars who hunt deer. Prey is more concentrated, and forced to use the same trails when the snow gets deep. For cougars, winter is a time of plenty.
In winter, deer will congregate in loose groups in favorable habitat. These herds can consist of family groups—that is, does with this year’s fawns. Sometimes, the boys hang out together, and bachelor groups of bucks will form away from the does and fawns. Herding up can be an advantage: more eyes to watch for cougars and other predators. Herding up also can be a disadvantage because more animals in small areas creates pressure on food resources. Large groups also can be more vulnerable to disturbance.
Humans and deer
Human activities can have profound impacts on wintering deer. Many times deer will spook and run from dogs, as well as people on foot, on ATV’s, on snowmobiles, and sometimes in standard vehicles. This burns precious energy reserves that could make a difference between life and death for the deer, especially with young, injured, or old animals. These human-induced stressors should be minimized in areas where deer are known to winter. Visitors and residents should keep their dogs under control and avoid spooking deer by walking too close. Special winter area closures are in effect around the state in certain special locations, but we should all be cognizant of the needs of wintering deer everywhere and avoid unnecessary disturbance.
Cars and deer have a rocky relationship. Those rolling, shiny metal boxes are generally bad news for deer. But, ironically, deer can acclimate to vehicles, especially moving ones, knowing they do not usually pose a threat. (Watch what happens with roadside deer if you stop your car, and then open the door.) Road kills usually occur at night, when deer alongside the road are blinded by headlights and leap in front of the oncoming vehicle. It is advisable to slow down to 45 mph or less in areas where deer frequent to give more time to spot and evade deer. Winter can be particularly bad for road kill, as more deer are in the lowlands where more of the roads are. Be careful out there!
Deer are primarily browsers, eating the new growth and terminal branches on desired shrubby plants. Winter range management should entail encouragement of these species, including planting in areas denuded from fire or other disturbances. Preferred winter browse species on the eastside for both mule and whitetail deer include: serviceberry, sagebrush, Ceonothus (deerbrush), willow and bitterbrush. Black-tailed deer on the westside tend to have a wider array of shrub species to choose from, but some favorites are: serviceberry, vine maple, red alder, elderberry, blackberry, thimbleberry, salmonberry, and willow.
The worst possible conditions for wintering deer are years when deep snow is followed by rain that freezes into a thick coat of ice atop the snow, preventing deer from pawing down to forage. These conditions can spell doom for many, many, deer resulting in significant population reductions, as has happened before in Washington. Fawns are especially vulnerable in such conditions, and at those times, humans need to be particularly sensitive to wintering deer. In years of low snowfall, browse is generally available, and deer entering the winter with adequate fat reserves stand a good chance of surviving. Fires can damage winter range productivity by removal of shrubs in the short term, but often can result in improved forage conditions with enough time. Supplemental feeding is generally frowned upon, but can be employed as an emergency measure in dire situations. The best option for managing deer in winter is to provide them with good forage in desired areas with limited human disturbance.
Deer are iconic wildlife for all of us in Washington. They share our landscape, and increasingly, the areas around our homes. Winter is the time when our actions can have particularly big effects on them. For more information on deer in Washington, consult the Washington Department of Fish and Wildlife’s online publication, “Living with Deer.”
For questions on wildlife stewardship and habitat enhancement potential on your forest lands, please contact me at Ken.Bevis@dnr.wa.gov.
By Ken Bevis, DNR Stewardship Wildlife Biologist