Winter roundup: weather most likely to impact pheasant, grouse
It's too early to tell exactly what impact this winter's weather will have on all Minnesota game animals, but Minnesota Department of Natural Resources (DNR) wildlife biologists suspect that pheasants and grouse likely will be the species most affected.
At least 18 inches of snow cover the ground throughout Minnesota's pheasant range. A number of birds have and will fall victim to the deep snow that covers fields and fills ditches throughout much of southern Minnesota.
"Grasslands and many cattail marshes, the preferred pheasant habitat, are filled with snow and uninhabitable," said Kurt Harloldson, DNR wildlife researcher. "Pheasants have had to find other woody cover such as shrub swamps and farm groves."
While those areas provide some protection, they expose pheasants to cold winds and put them more at risk to predators as the birds forage for food in more open spaces for a longer time.
Despite the expected winter kill, the population can and does recover. The key is pheasants' ability to find relatively dry grassland nesting areas that allow the birds to hatch and nurture a healthy and viable breeding population.
"There's nothing we can do about the weather but adequate grassland for nesting habitat is a concern," Haroldson said. "Many Conservation Reserve Program (CRP) acres that once provided that habitat have been or are being returned to production. That may have more of an impact on the population than this winter's weather."
In northeastern Minnesota, an icy crust has formed over snow, creating conditions that may be forcing grouse to roost in and under short, close-clumped conifer trees rather than burrowing into their preferred roosts in six to 10 inches of fluffy snow.
Grouse are uniquely adapted to survive Minnesota winters. Roosting in deep, fluffy snow for up to 20 hours at a time insulates the birds from cold, protects them from the wind and reduces their exposure to predators.
"When grouse can't burrow into the snow to roost, they often select roost sites on the lower branches of short, close-clumped stands of spruce and balsam fir," said Jeff Lightfoot, DNR northeast region wildlife manager. "These roosts make it more difficult for grouse to retain radiant heat, and can increase exposure to predators."
Wildlife biologists believe that those ruffed grouse able to snow roost near deciduous trees
- such as aspen - that provide high-quality winter food, have a greater chance of surviving. Birds that are unable to snow roost use more energy maintaining body heat and out of necessity are out in the open feeding more often.
Lightfoot said it is tough to tell what effect crusted snow and other environmental conditions have on our ruffed grouse because so many different factors influence their population throughout the year. Annual counts of drumming males throughout the state's forested regions suggest they are at or near their approximate 10-year peak in population cycle.
"Our drumming counts this spring will provide us with a good idea of the status of the population after this winter's icy snows," Lightfoot said.
Minnesota's wild turkeys will fare better than pheasants this winter because they are larger birds and their primary habitat is wooded areas, which provide better shelter.
Like pheasants, turkeys are ground feeders. But their larger size helps them cope better in deep snow. Turkeys also will follow deer trails and will scratch the ground to uncover food sources.
This winter's weather is expected to have a negligible impact on northern deer populations. The Winter Severity Index (WSI), which is used to measure winter's impact on deer, is well below moderate levels. WSI values vary greatly across northern Minnesota but winters have generally been considered mild to moderate since the severe winters of 1995-96, 1996-97 and the 2008 winter, which was severe in places.
"This will be a mild winter for deer in most of Minnesota, just so we don't get deep snow or long cold snaps through mid- to late March," said Lou Cornicelli, DNR big game program coordinator.
Deer have become stressed in parts of southwest Minnesota due to significant snowfall. "We have lost fawns and weaker deer in the Southwest where snow depths are causing some issues," said DNR Regional Wildlife Manager Ken Varland. "We are seeing significant crop depredation concerns, especially in the Marshall, Slayton, Windom and Lac qui Parle areas."
Varland said area wildlife staffs in southern Minnesota are spending at least a portion of each day working with landowners who are experiencing problems, especially around farmsteads. Deer will seek any available food source that is accessible."
Moose and elk
In the far north, moose and elk are hardy and fare well even in harsh winters. A cool and snowy October may actually benefit Minnesota's moose population in the long run. Moose are stressed in the winter when daytime temperatures exceed 23 degrees. Temperatures did rise above that during some days in January.
"With the fall we had in the moose range, we may see fewer incidences of moose infected with winter ticks," said Mark Lenarz, DNR wildlife biologist. "Ticks thrive on warm falls and springs."