The holiday season is upon us. We have made it through Thanksgiving and deer season and are rolling full steam ahead. Festivus, Christmas and Kwanzaa are just around the corner! And with those celebrations comes food, lots of food. I bake cookies once a year, put them in pretty tins, and distribute to the chosen few.
The period between Thanksgiving and New Year’s is filled with turkey and stuffing; pies and parties; cocktails and appetizers; and brunches and cinnamon buns. Those of us trying to watch our figure often dread the endless temptations presented to us on what seems like a daily basis. But while we’re stuffing our faces, most species are laying low and tightening their belts.
It is no secret that food is scarce for those that don’t forage at a grocery store.
Strictly speaking, basal metabolism is the amount of energy burned by a fasting, non-reproductive adult animal that is inactive but not sleeping in a thermal neutral environment. While it has its place in understanding energy needs, blinking, sneezing, or twitching an ear changes it. There are also variations based on age, weight, and sex. When you start adding in real activities needed for survival like walking, foraging, and digestion, you can see how metabolic rate and energy needs change and fluctuate over seasons and life stages.
What’s a deer to do during the cold, brown winter to get the energy they need to make to the over side? They can’t pull a Brian Wilson.
Instead, deer are akin to walking hibernators. They fatten up in the summer and fall then use those fat stores during the winter.
Deer are all about conservation in the winter. Frugal spenders of finite energy reserves. If they go bankrupt, the consequence is death!
Winter forage quality varies based on the species but they all pretty much suck when compared to the summer smorgasbord. “Preferred” winter browse like aspen and maple are digested at 30% or less compare this to summer forage which is digested at 50-80%. Acorns weigh in at 48% digestible energy which explains why they are coveted by all nut eaters great and small. Regardless, if you have to burn twice as many calories to walk to AND digest it, it’s not worth ponying up to the table.
Deer voluntarily restrict food intake and activity in winter. Indeed, deer in nutritional studies given access to as much browse as they wanted did not consume it all and still lost weight in winter. Deer may lose 20-30% of their body weight in winter.
The other factor in all of this is what is available on the landscape. Winter browse nutritional content may suck but some suck a little less than others. For example, deer on Anticosti Island, Quebec, have nearly completely extirpated balsam fir, their preferred winter forage, at browse height and are being forced to white spruce, a species normally avoided. In the study, fawns lost about the same amount of body weight whether they were eating balsam fir or white spruce. While both groups (voluntarily) reduced forage consumption over winter, those on the white spruce diet did not reduce consumption at the same rate as the balsam fir group. Suggesting that deer can partly compensate for decrease in forage quality by consuming more of it.
Yes, the longer winter hangs on the less selective deer get.
Come January, there won’t be any Christmas cookies left either. And we, too, will be buckling down dreaming of warm days and spring flowers. Until then, deer will lay low, nibble on what is close by, and loose that winter weight.
PGC Deer and Elk Section
PS. I updated the post to include links to my cookie recipes. A few notes:
For the maples bars, I substitute butterscotch chips for the cinnamon chips.
For the cranberry oatmeal, I omit the raisins and double the cranberries using fresh not dried.
For the rugelach, omit the raisins from the filling it make a mess when you cut them for rolling!