Extreme cold and low/no snow are the worst conditions for ruffed grouse in winter. Many areas in the upper Midwest have had lower than normal snow amounts this year leading to poor snow roosting conditions for ruffed grouse. Grouse are very well adapted to heavy snowfall and will burrow or dive bomb into deep fluffy snow to help avoid detection by predators and conserve a surprising amount of heat. Research has shown that the temperature under a 6” deep snow pack stays around 32 degrees F and does not get below 20 degrees F regardless of the temperature above the snow. Approximately 25 degrees also happens to be the tipping point after which a grouse needs to start speeding up its metabolism and using extra energy to stay warm. Coincidence?
The past two winters in northern Michigan provided excellent snow roosting conditions with deep fluffy snow and no rain or crusting of the snowpack from mid- November until nearly April in some places. This year, snow totals are below normal and much of it has been wet or has crusted over. The following graphs from NOAA show how far behind some places are this season. http://www.weather.gov/apx/snowgraph_ytd . The winter storm currently hitting the northern lower peninsula and upper peninsula is actually good news for ruffed grouse and will provide shelter from the frigid conditions to follow.
Here are two pictures of a ruffed grouse snow roost taken during a habitat project in Emmett County, Michigan on February 26, 2014 during an exceptional snow roosting winter. The first is the entry via dive bomb followed by a couple of feet of burrowing.
The second is the exit of the roost and a short walk before taking flight, most likely into the aspen branches above to get a meal of buds before finding a new place to roost.
Additional photos provided RGS Biologist Scott Walter, Click to enlarge:
