Mule deer on the move
Break from snow, cold good for finding food
The wind came steady out of the southwest all night Sunday and carried the snow with it.
By early Monday morning, the few motorists on Grand County Road 1, which goes from State Bridge to Kremmling, no longer were bucking the big drifts of the prior day’s storm.
According to the Colorado Climate Center, this piece of Grand County and Middle Park received nearly 200 percent of normal precipitation in December, although most of the weekend snow probably blew into Jackson County and then to Wyoming.
The cold and the blowing snow makes riding ski lifts, walking the dog and driving difficult, but it may help save mule deer herds.
This part of Colorado is deer-rich, and the day after Sunday’s storm their tracks made hieroglyphs across snow-covered fields.
Except for two, a doe and yearling seen walking through a belly-deep roadside drift, the rest of the deer were scattered across wind-blown ridges and hillsides where they could find winter forage.
“The snow depth isn’t bad,” said Lyle Sidener, Area Wildlife Manager for Colorado Parks and Wildlife in Hot Sulphur Springs. “And driving (U.S. Highway) 40 from Hot Sulphur Springs to Kremmling, we still see a lot of exposed ridge tops, and from that standpoint it’s really good.”
Mule deer are picky and opportunistic browsers, a majority of their diet being forbs (weeds) and browse (leaves and twigs of woody shrubs).
Although this makes it easier finding winter feed, deer have a small digestive system that needs to be replenished often. When high-quality forage isn’t available, mule deer have difficulties satisfying their nutrition requirements.
Also, deep and crusted snow can prevent deer from reaching food sources.
Winter, when vegetation has lost the majority of its nutritional value, is a time of slow starvation for big game.
Trudging through heavy and/or crusted snows in search of hidden forage burns the life-saving calories stored as fat during summer months.
“This year started off with the early December snow and cold, and it had us wondering how long this could last,” said J Wenum, area wildlife manager for the Gunnison Basin. “Fortunately it’s mellowed since then. We’re still cold — this is Gunnison, after all — but the snowfall hasn’t continued.”
Even though mule deer and other ungulates have adapted to long periods of cold-weather deprivation, winter isn’t easier, but their bodies are able to survive longer.
“The general rule of thumb, especially for adult female deer, is if we can get to the first of January without a major cold snap or a long, extended period of subzero cold with deep and crusted snow, we are in pretty good shape for survival,” said Brad Petch, state terrestrial biologist for Colorado Parks and Wildlife.
Wenum and terrestrial biologist Brandon Diamond this week began their annual aerial census of big-game herds, and the preliminary news is positive.
“At the lower elevations things look really good,” Wenum said. “There is some snow, but it’s loose with a lot of brush sticking up. The animals are spread out and dispersed, so there’s plenty of access to forage and food.
“All the animals we saw look to be in really good body condition.”
The summer rains increased the vegetation at higher elevations and kept deer and elk herds scattered, as many hunters discovered this past hunting season.
The deer stay high as long as the snow and cold and forage allows, feeding where there is less human intrusion.
“We’ve been seeing deer at 8,000 and 8,500 feet, which tells me they haven’t yet had the need to move to winter range proper,” Sidener said.
Wenum, 120 miles south in Gunnison, reports the deer there also are staying high, although the subzero temperatures in the valley floors may have some impact.
“Because this is such a cold-air sink, the lower elevations tend to be colder, so we don’t see a lot of wintering big game (in the valleys) unless they are forced there by the snow,” Wenum said. “We’re still seeing animals at what I’d call mid-elevations, at least for winter range, and at moderately high elevation for this time of year.
“The air temperature up there is moderate and there’s less people.”
The first aerial surveys indicate the deer are in good shape, Wenum said.
“I’m really pleased with what we are seeing,” he said. “The deer are dispersed and in good condition. It’s turning out to be a pretty good winter, at least at this point.”