Wednesday, December 11, 2013
By BOB HUMPHREY
Deer hunting is a contest between hunter and hunted. Game laws designed to ensure the long-term viability of a renewable resource give the hunted a decided edge. But knowing the patterns of your prey can go a long way toward improving your already long odds. And predicting patterns becomes easier if you know why prey do what they do.
White-tailed deer are crepuscular, meaning they are most active around dawn and dusk. If you were to graph daily activity patterns -- and numerous studies have done so -- you would see two peaks, with the level of activity decreasing on either side.
Deer do move outside of peak periods, but increasingly less as you move away from the prime times in either direction. All other things being equal, the closer you are to peak activity periods, the higher the likelihood of seeing deer. However, all other things are seldom equal -- more on that in a bit.
Deer are ruminants. They have a complex, four-chambered stomach for digesting a diverse array of plant food. They consume as much as they can in a short period, then bed down to allow the first compartment of the stomach to soften course foods. They then regurgitate the semi-digested mass and re-chew it to further break down plant matter. Food is re-swallowed, then passes on to the next chamber.
At this point the deer could head off to bed for the day. Some do, and some don't. I've witnessed a minor activity period an hour or two after daylight enough times to think it's more than mere coincidence -- and though it's largely speculation, I have a theory as to why this happens. With the first chamber of the stomach empty, deer may feel hungry again. They can feed for an hour or so and refill the first chamber again before bedding for the day.
Obviously, this can vary depending on what they eat. Early in the fall they're still eating a lot of herbaceous vegetation, which is easily digestible, so they're less active outside peak periods. Later, they switch to more course, woody vegetation, which is less nutritious and harder to digest. They have to move and eat more to obtain the same amount of nutrition. And as temperatures decrease, their caloric demands increase, prompting further daytime activity.
Warm temperatures may have the opposite effect, for several reasons. One is that deer don't burn as many calories when it's warm, and don't need to acquire as many calories. The other is that by November they're wearing fur coats, and moving might actually be uncomfortable. One study on northern deer showed activity levels dropping off dramatically as temperatures approach 50 degrees.
November is also hunting season, and when you add other hunters to the mix, things can change dramatically. In the short term, more hunters in the woods could result in increased deer movement outside of peak times as mobile hunters jump bedded deer. In the long term, however, increased disturbance will shorten the activity curve -- reducing the period of activity -- and shift activity more away from daylight hours.
Another factor is the fall breeding season -- the rut. Bucks are moving more to find does. It's easier during peak periods when does are more active and thus easier to find. Eventually the does bed down, but the bucks keep looking, and may have to travel farther to find them. That's why mid-to-late morning can be a good time to spot a cruising buck during the rut.
All things considered, predicting deer movement is still a fairly tenuous exercise. Deer may follow general patterns, all of which can be altered by an array of circumstances and occurrences. The deer still hold a decided edge, and the likelihood of one showing up at your location any time is still extremely low. But by hedging your bets, you can sometimes tilt the odds infinitesimally in your direction.
Bob Humphrey is a freelance writer and registered Maine Guide who lives in Pownal. He can be contacted at: