Winter Conditions

Folks,

Just over a week ago, I sent out the below message regarding condition of ungulates given ongoing winter conditions.  I'd like to provide an update and remind all that I would appreciate hearing about any mortality you observe. Over the past week, I have received scattered and isolated reports of ungulate mortality associated with conditions.  Those reports included:  three dead mule deer fawns in a yard near Ennis; four or five dead antelope along the East Bench (west side of the Ruby Mountains), two reports of one and two dead white-tailed deer in the Madison Valley; and one report of seven dead white-tailed deer in the Ruby Valley.

 Just after I sent the previous report, the Ruby Valley received an additional 2-3 inches of snow.  Although temperatures have remained mostly below freezing, afternoon sun has been common and two days have brought highs in the upper 30s, resulting in noticeable settling and some melting of snow.  Settling brings some benefit and different challenges to wintering ungulates relative to deep and soft snow.  Settling does reduce snow depth which makes it easier for ungulates to move through while its soft (during the warm part of the day) and it often re-exposes shrubs which ungulates can use as a browse resource.  Settling also makes snow denser and afternoon melt facilitates night time freezing of top layers--creating a hard crust.  Both can impact an ungulates ability to travel through snow while it is crusted (during the night and morning) and move snow for foraging.  Conditions remain difficult across the Ruby and Madison valleys, especially for antelope and white-tailed deer attempting to find forage on relatively level areas.  I have observed the wintering herd of antelope between Twin Bridges and Sheridan foraging in the DOT gravel lot and south of Highway 287. This is the first time I have observed this--suggesting they are struggling to find recourses on typical winter range and ranging wider than typical. A positive sign is that they continue to move around. Ungulates without the energy to move and forage are likely nearing death. I completed moose surveys in hunting districts 331, 332, 333, and 334 on Sunday and observed just over 300 moose.  Except for one emaciated moose observed in the Centennial Mountains, all appeared to be in good condition.  South aspects along the west Snowcrest and east Blacktail Mountains were mostly bare of snow.  Elk that were wintering along the east Blacktail Mountains had moved up in elevation and into Little Sage Creek since we surveyed them just over a week ago.

The storm currently moving through the region mostly missed the Ruby Valley. Current forecast is for relatively low chance of snow accumulation through tonight, followed by sun and warmer temperatures over the next several days.  I expect a fair amount of snowmelt will occur--bringing ungulates some needed relief. I caution folks to avoid disturbing ungulates through the remainder of these deep snow conditions and beyond.  Moving through deep and dense snow is very taxing on ungulates with low energy reserve. Disturbing them could also mean displacing them from areas they are finding needed forage or an aspect that is out of the wind and exposed to sun energy.  Even as areas bare of snow, I caution disturbing ungulates for a while.  Low nutritional condition will remain until green-up forage allows for slow recovery.  Displacing ungulates during the early spring often leads to them moving through remaining snow drifts or onto north and east aspects where snow remains deep.

As of today, I believe elk and moose are faring well across my management area.  The mule deer I observed while completing moose surveys appeared to be in good condition. Many are browsing shrubs on steep aspects. Those in the Madison Valley and Ruby and Tobacco Root Mountains are experiencing the greatest snow depth and hardest conditions. If mortality occurs, I expect it would start in the Madison Valley, where conditions are tough, quality winter range is limited, and competition with elk is high. Antelope and white-tailed deer are being challenged in the Madison and Ruby valleys. I expect at least scattered mortality to continue in these areas. Population-level mortality will be determined by weather over the next couple of weeks. Antelope south of the Ruby Valley appear to be in good condition. I will continue to monitor conditions across ungulate winter range, document known mortality, and provide another update in about a week.  If you have any questions, please feel free to contact me. 

Dean Waltee

Wildlife Biologist

Montana Fish, Wildlife and Parks

Sheridan, MT