OK, I know timing the rut is an oft-visited subject. The fact is, it's of great interest to whitetail hunters and a topic we should probably cover at least once a year. Research from Maine to Montana and Florida to Texas shows daytime deer movement peaks during the rut. The more deer move, the better your odds of encountering them. The rub (if you'll pardon the obvious pun) becomes knowing exactly when that peak activity will occur.
TIMING IS EVERYTHING
The rut's trigger is photoperiod — the amount of daylight per 24 hours — or, more precisely, the change in daylight hours. Diminishing daylight in the fall triggers physiological (hormonal) changes that, in turn, result in behavioral changes in both bucks and does. Bucks become more aggressive toward one another and increasingly more attracted to members of the opposite sex. With the change in daylight and this increased attention, does eventually come into estrus and ultimately yield to their suitors.
One problem for hunters is that the timing of the rut varies considerably over the aforementioned geographic span, and anywhere else whitetails occur. Those of us who live in the north have it a lot easier when it comes to predicting the rut. The difference in hours of daylight from summer to winter is much greater. Thus, the fall decrease in daylight hours is more abrupt and distinct.
Perhaps more important is the influence of climate. Seasonal climate change in the north is just as great as the change in daylight hours, and harsh winter conditions put additional selective pressure on northern deer, particularly with regard to reproduction.
Does must be able to optimize available food resources when pregnant and ensure their fawns are born into a favorable environment. If they breed too early, the higher energy demands of fetal development may occur at a time of food scarcity. If bred too late, they may not have sufficient time to recover before the onset of the next winter. Meanwhile, if fawns are born too early, there may not be sufficient food resources to support lactating females and later, weaned fawns. If they're born too late, they won't have achieved sufficient growth and body development to survive the oncoming winter. Thus, natural selection has fine-tuned the northern rut to occur during a fairly narrow window, at roughly the same time every year.
The southern situation is much different. With photoperiod change less dramatic and climate change less severe, selective pressures are less intense. Research suggests rut timing may be more influenced by genetics, maternal factors and herd demographics, the former being further exacerbated by northern deer relocated to the south. Seasonal changes in moisture may also be a factor, particularly in arid regions, though more research is needed here.
WHAT ABOUT THE MOON?
There are several theories about moon position or phase and how it relates to rut timing. The basis of those theories ranges from ancient superstition to some fairly logical thinking. And a fair number of hunters have experienced success by adhering to them. I wouldn't dismiss any of them out of hand; anything that boosts your confidence or gets you out in the woods increases your chances. However, there is no empirical evidence to date supporting any of the moon theories.
Population demographics and management also play a role in both northern and southern deer. From research, we know the rut tends be more synchronous, shorter and more intense in herds with more balanced sex and age ratios. The opposite is true for populations that are poorly managed, or managed more for quantity and less for quality.
WHAT IS THE RUT?
In order to maximize your time afield, it also helps to understand exactly what is meant by "the rut." There are several definitions. Briefly, the rut is the mating period for whitetail deer (and all cervids, for that matter). For each deer, it involves a process of getting ready (priming). Bucks build up their strength and status through rubbing, sparring and fighting, then begin courting by scraping, seeking and chasing. Eventually, a doe relents, and the pair moves off to some secluded location for a period of 12-24 hours.
To a biologist, peak rut is the peak-breeding period, when the majority of bucks and does are paired up and in the process of actual mating. Daytime movement, at least on a localized level, may drop off considerably during this time. To the hunter, peak rut is just prior to this, when the bucks are on their feet all day, actively seeking, and when they find them, chasing does that may be nearing peak estrus.
This is that magical period when mature bucks drop their guard and, as a result, are most vulnerable. Bear in mind, however, that predictability goes right out the window during this time. Forget patterning. You never know when a buck might show up, or which buck it will be. Bucks you've been hunting all fall may suddenly disappear, only to be replaced by others that previously never appeared on your scouting cameras.
Increased deer movement during the rut offers distinct advantages, primarily greater odds of encountering a deer. Of course, you still have to pick the right place. And if you're after a specific deer, or even a particular age or sex, the situation becomes more problematic. Still, you can hedge your bets by shifting your efforts toward areas with a higher likelihood of daytime deer movement. But that's a topic we'll save for another day. Meanwhile, the best time to be in the woods is still whenever the season is open.