Deer Biologists - Opinion Wanted
Whitetail Deer
I'm curious on what impact the upcoming weather is going to have on deer here in Manitoba and trying not to fear the worst. We've got what looks like a legitimate 20" of snow or so in the bushy areas, and windswept are different, but there is quite a bit of snow. I know my front yard would be well over 24".
Anyways, throughout the winter our historical daily average high is about 7F and lows about -10F. This means we often get spells like last week where for a week or so the highs are -11F and the lows are about -26F. These temps are not including windchill. To get to the point, it looks like mid week this week we are supposed to get a few days right at/and one day above freezing with sun. Stuff is going to melt, form a crust, and then freeze over. Hard. What does this do to the deer? Is it basically all dependent on the winter after that? Our winter normally runs well into March and can go well into April. Thankfully our November was mild and gave them a good start to the winter.
We finally had two good winters in a row. Prior to that we had 3 of 4 winters that were brutal. Each of those winters cost us nearly 40% of the deer herd and numbers are very down. Not that I can control it, but I'd hate to have another bad killer winter. Curious if there is anecdotal evidence of what happens in situations like this. I imagine the coyotes will be running them down hard as the deer break through the crust and the dogs run on top. The predators will be eating well. Only positive is it will make them more susceptible to calling as they can move well.
We have 3-4 feet in the swamps up here on the border. If the deer have good softwood cover, they can survive. Those big fir and spruce hold a lot of snow and the deer will beat down their trails. Deer normally enter winter with 2-3 months of fat reserves. March and April are critical on deer, and up here some die in early May as their gut bacteria can't adjust in time to green forage. I just cruised a deer yard and the deer are in fine shape. Their trails are like highways. I did see some signs of enteritis behind my property because someone is really putting the grain out. I also found one deer that died from eating bread. They cannot digest glutin. I spoke with the guy feeding them and he was mortified. I carry a small saw with me and hinge cut a few maples when cruising. Good cover, natural feed, best winter solution along with trapping and predator hunting. In the end though, tough winters are natures way of making the species stronger as it is survival of the fittest, and the weaker genes get culled out.
I'm not a biologist but I did stay at a Holiday Inn Express once. Lawdy gave some sage advice. March and April are critical here for deer and I'm only a couple state below you. The deer normally don't start dying until then unless they were unable to build up their normal reserves heading into winter. If you get some bad weather in April/May that pushes back the green up then I'd be worried.
Lawdy,
I am no veterinarian, but like Brotsky, I stayed at a Holiday Inn once. Enterotoxemia, as I understand it, occurs when deer try to shift from a diet consisting of winter browse to a higher energy food source (as a result of residents feeding them corn, etc) in a very short period of time. Their digestive system simply can't make the conversion that quickly.....which in extreme cases can lead to death. However, I know of an 83 year old lady that refuses to quit feeding the deer white bread every winter....and it isn't killing deer....probably because they are used to it. Now, if it was the dead of winter, and they had never had bread before, that might be a different story. I agree with your course of action though.....using pruning shears to cut some limbs for them to browse upon, would be a more effective (and humane) alternative....
Everyone on this website is a deer biologist.
Here's how Wisconsin's does it Wisconsin's WSI measurements are recorded annually from Dec. 1 through April 30 at
43 stations. One point is accumulated for each day temperatures fall below zero and each day the snow depth is greater than 18 inches.
Winter conditions are considered mild if the station accumulates fewer than 50 points, moderate if between 51 and 80 points, severe if between 81 and 100, and very severe if over 100. Here's how Minnesota calculates there's The index adds one point for each day the temperature falls below zero and another point for each day the snow depth is greater than 15 inches. End-of-season values of fewer than 100 points indicate a mild winter, while values of more than 180 indicate a severe winter.
Our deer up here are deep woods deer. They eat mainly woody browse and lower their metabolism as winter sets in. We have no oaks up here and beechnuts disappear fast. One food they need both for nutrition and keeping the optimal chemical balance in their gut is an arboreal lichen called "old man's beard." You will see this growing and hanging off dead fir and balsam branches. Because they are ruminants, sudden changes in diet can be deadly if the bacteria in their gut can't digest the new food. If you find a winter-killed deer, break open a femur and check out the marrow. If that deer starved to death, the marrow will be just a thin string in the center. The biggest killer of deer up here is not starvation, it is exposure as deer yards get cut. I found 36 deer in one yard alone that died of exposure several years ago. The feds clearcut a yard 4 years ago and 23 died. Pushing for selective, sustainable logging while saving and enhancing deer yards has been my passion. If all the money thrown at buying grain up here went into habitat improvement, our deer would be so much better off. The town of Pittsburg, NH loses 100 deer, on the average, every winter to car/truck collisions as deer go house to house looking for handouts. One radio-collared spikehorn averaged 11 miles per day. He was hit by a car crossing Rte 3 to get fed. As far as feeding bread to deer, check with your own biologists and they will verify the fact that deer cannot tolerate glutin. If there are any cattle farmers on this site they could comment on the dangers of switching foods on ruminants as deer and cows are ruminants. My degree was a BS in Zoology with a graduate concentration in wildlife. I minored in Physics and Chemistry. I taught Biology and Physics for 36 years and now do wildlife survey work along with a lynx project. I was fortunate to have had some great profs at UNH and spent a lot of time in the field. Of course, that was 50 years ago, and things change.
Thanks guys. These types of threads sure help me learn!
FWIW... A few years ago after some really big snowfalls here, I went to the local park and circled the thick, nasty stuff to see if I could check up on the deer there. I kept circling the area in a tightening spiral, not finding any tracks, and had about concluded that they had moved out entirely when I bumped a nice, young 8-pt.
He had been parked in an area the size of our living room for almost 3 weeks. They don't get stir-crazy the way we do, so he had just been hunkered down, apparently eating some snow and living off of reserves.
They gear down, metabolically, so they don't need much so long as they don't get harassed by dogs and coyotes, but those thick crusts can turn a cocker spaniel into a deer-killing machine...
My degree was BS in Biology as well, heavy on natural history and winter ecology, then I went to U Wyo for a couple of years of graduate work in ecology/parasite ecology/evolutionary biology... got to hang with a bunch of guys from the F&G Co-Op unit, as well as the guy who was running the Jackson Elk Refuge at the time... Lot of good people and VERY good hunters in that bunch!
Both Lawdy and GF also mention something that has always intrigued me about winter whitetails....and that is their ability to survive for rather extended periods of time with essentially no/little nourishment, even though the winter is upon them directly after the rut, when they have already run their bodies ragged. I wonder if they are just so frigging tough that they can get through all but the worst of winters, or if their bodies actually "shut down" to an extent.....not to the extent of a bear in hibernation (who pulse might be four beats per minute in the winter) but at least to a point where minimal nutrition is required for anything but regulating body temperature ( and the occasional need to evade a coyote or similar predator).
Lawdy, PM sent.
I am also not a deer biologist, but I have stayed at a few Holiday Inn's and the walls are pretty thin, but they do have a decent breakfast.
Biologist or not, I think we can all agree that habitat is the key to a healthy deer herd. They are very adaptable amazing animals.
Very interesting - thanks guys! Those stories remind me of one I read about a hunter who lived up in Alberta and one day using his spotting scope he glassed up a nice mulie bedded, I think it was reasonably close to a field in some shrub-type stuff. Anyways, they had had a huge dump and he kept seeing it day after day in exactly the same spot, unmoving. After a while he simply concluded it was dead. I can't remember how many days it was and then all of a sudden it got up and walked away. I've heard that they don't hibernate like a bear, but can go into an almost semi-hibernistic (if that's a word) state. I wonder what happens if they need to break out of that state quickly do to approaching predators?
Thanks for the input fellas.
