Deer Survival:
Where Have All the Deer Yards Gone?

by V. Paul Reynolds

With the onslaught of winter - plummeting temperatures, high winds and driving snow - Maine's whitetail deer population is digging in for the duration. To survive, our statewide deer population, estimated to be in excess of 250,000, must find two things: thermal shelter and browse. These are found in places called deer yards, or deer wintering areas. According to Maine's deer biologist Gerry Lavigne, "deer are highly dependent on wintering habitat for survival every year."

Typically, a deer yard will be an area where there is what wildlife biologists call a "high softwood crown closure." The canopies of large softwood trees provide some thermal shelter from deep snow, penetrating cold and bitter wind. Available browse in these deer yards usually consists of litterfall, which comprises leaves, twigs and aboreal lichen.

For deer, especially in the North and Western mountains of Maine, winter is a precarious life-and-death struggle. Depending upon winter's severity index, deer mortality can range from 3 percent to as high as 35 percent. In January and February, there is a slowing of a deer's metabolic rate with less demand for calories. Not only can deer resorb their muscle tissue to provide desperately needed calories, the accumulated fat in their bodies can be burned as body fuel when winter browse is scarce. During the winter yarding period, which averages about 135 days in the north and close to 100 days in the more southerly sections of the state, fragile fawns and older bucks that are worn out from the fall rut are the most vulnerable to winter mortality. Many of Maine's deer yards have been used by wintering whitetails repeatedly for as long as 50 years.

Food and warmth aren't the only problems that confront wintering whitetails. A recent study indicates that coyotes take as many deer each year as deer hunters. In fact, given Maine's run of relatively mild winters, more wintering deer are being lost to predation than malnutrition.

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As state biologists prepare Maine's next 15-year plan for deer management, which is due to be approved early this year, deer wintering habitat (deer yards) has become the focal point. Over the past decade, there has been a marked decline in deer wintering areas, especially in Northern and Eastern Maine where deer populations are down.

When compared with the ideal percentage of deer wintering areas, which is about 10 percent of the land base, the statistics are striking:

  • Currently, there are 2,800 known deer wintering areas in Maine.
  • In the late 1950s and early 1960s, there were in excess of 4,000 deer wintering areas statewide.
  • In Northern Maine (Wildlife Management Districts 1-6), deer yards represent a mere 2 percent of the forested land base. That figure was once in excess of 10 percent.
  • In some parts of Eastern Maine (Wildlife Management District 19) the deer wintering land base has shrunk to an incredible low of 1.2 percent.

Why the significant decline in deer yards? According to Lavigne, a combination of massive spruce budworm infestation in the 1970s and aggressive forest cutting practices are to blame for the loss of deer yards. Despite the ambitious 15-year goals to be outlined in the 15-year deer management plan, the short-term outlook for deer wintering areas may be plagued by an underlying economic reality. During the next decade, according to Lavigne, Maine is likely to experience a continued decline of deer wintering areas as market demands increase for softwood products.

For many years, Maine's deer wintering habitat has been under the jurisdictional eye of the Land Use Regulation Commission (LURC). Under LURC, the zoning approach to deer yard protection, according to Lavigne, leaves much to be desired. Although it is still early in the game, wildlife managers seemed to be having better success by protecting deer yards through cooperative working agreements between large timberland owners and the Fish and Wildlife Department. Champion International, for example, has been working closely with wildlife managers in designating deer wintering habitat for protection. According to Lavigne, upwards of 15 percent of Champion's timberland base is now protected deer wintering areas. Other large landowners are expected to come aboard as national mega-retailers such as Home Depot insist on doing business only with environmentally enlightened manufacturers.

Increasing the number and quality of Maine's deer wintering areas, is a key component of the 15-year deer management plan to be approved this year. This objective reflects the direct, known relationship between widely varying deer populations and widely varying deer wintering areas from Kittery to Fort Kent.

The management plan will set deer population goals that include a range of between 10 and 20 deer per square mile, depending upon geography, topography and weather conditions. In Northern Maine, a population of 10 deer per square mile, which is far more than current populations, will require 780,000 acres of wintering areas, or 8 percent of the landbase. (It is currently about 2 percent).

In Western Maine, the goal is 15 deer per square mile, which will require a wintering area land base of about 9.5 percent( It's currently about 4.1 percent).

In Downeast Maine, the goal is 15 deer per square mile. This is an ambitious goal in as much as the current wintering areas in this deer-poor area represent about 1.5 percent of the existing land base.

In Central Maine, where current deer populations are thriving, the 15-year goal is 15 to 20 deer per square mile. According to Lavigne, deer wintering areas in this part of Maine are "pretty decent," though he concedes that deer wintering habitat in this area is "poorly understood."

In Southern and Coastal Maine, the problem ironically is not deer yards as much as it is an excess of deer in some semi-rural areas and residential perimeters where hunting activity is low, or prohibited by local gun discharge ordinances. There, deer populations vary from 10 to 100 animals per square mile! The deer management challenge is more social than biological. A dramatically higher deer harvest with more areas open to controlled deer hunts will be required to maintain deer populations at socially tolerable levels.

If the 15-year deer management plan is successful, the end result by 2015 will be a deer herd of 384,000 statewide (13 deer per square mile), and an annual deer harvest by hunters of about 46,000. This will require a dramatic turnabout in the quantity and quality of Maine's deer wintering areas or deer yards. Lavigne says that the plan calls for 1.7 million acres of protected deer yards, or about 9.1 percent of state timberland.

Maine Deer Yards

BEST LAND BASE

WMD 16 9.5%

WMD 17 8.7%

WMD 22 10.8%

WMD 23 14.2%

WORST LAND BASE

WMD 6 1.4%

WMD 14 1.1%

WMD 19 1.2%

WMD 24 1.9%

WMD 29 1.0%





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