A white-tailed buck with huge body and antlers guards a doe in estrus during the fall rut. The buck’s hair is standing because other bucks are in the area, also coveting the doe. Bill Marchel/Star Tribune

It’s coming soon to a woodlot near you. Tree trunks are being maliciously stripped of their bark, bare spots of the forest floor becoming more common and bucks are more frequently seen crossing the road after dark with their nose to the ground. That magical period is nearly upon us and while deer hunters anxiously look forward to the whitetail rut, many don’t fully understand it.

The rut is the mating season for white-tailed deer, and includes all behaviors associated with that activity. It starts with preparation, intensifies with courtship and climaxes with breeding. It’s a dynamic and urgent time for both hunter and hunted.

Some time in early to mid-September, bucks shed the velvet on their antlers. Soon after they start rubbing trees to strengthen their neck muscles for combat. They also engage in modest sparring matches to sort out dominance and build strength and endurance. These behaviors signal the onset of the rut.

Next comes scraping, often in early to mid-October. Bucks paw the earth, removing leaves and duff and exposing bare ground. They then urinate in the scrape, leaving an olfactory signal that indicates their fitness and readiness to breed, The does aren’t ready yet, at least most of them aren’t. Hunters sometimes refer to this as pre-rut, but the rut is already well under way.

While being approached, harassed and even chased by bucks helps, the real trigger for readiness is day length. As the days grow shorter, physiological changes take place in both bucks and does that influence their behavior. Testosterone levels in bucks and estrogen levels in does increase. Bucks become more aggressive toward one another and does are getting closer to breeding condition. Bucks move more during daylight hours as they seek the first does entering estrus. Word goes out within the hunting community that the rut is on.

Often it’s the younger bucks that are first to take up the chase. Driven by instinct and the first whiffs of estrous they travel farther and wider, exposing themselves to danger. Meanwhile older, more experienced bucks save their energy. They have learned to wait for the period when hot does will be more abundant and easier to find.

Peak rut, or what most hunters think of as the rut, is when courtship activity becomes most intense. Bucks of all ages are now actively seeking and chasing does at or near breeding readiness. Theories abound on what triggers the timing, including moon phase, solunar tables, cold snaps and more. Decades of research have demonstrated that peak breeding is triggered by changes in day length, period. Because those changes are consistent from year to year, peak breeding occurs at the same time every year for any given area.

Biologists are quick to point out the distinction between peak rut and peak breeding. As noted, peak rut is the zenith of courtship-related activity: seeking, fighting, chasing. Peak breeding is when the majority of does are actually bred, and the latter occurs roughly a week to 10 days after the former.

It’s also important to understand that breeding occurs on a continuum. When conception dates are plotted on a graph, the result is what biologists call a bell curve, with most of the does being bred within a 7-10 day period, but decreasing numbers before and after. Some does may enter estrus and breed a full month before or after the peak breeding period. Those early does often trigger some of the aforementioned early rutting behavior among bucks.

Hunters often talk about different rut-related behaviors like seeking, chasing and breeding as phases of the rut. These phases do occur, but they’re not nearly as distinct as we might think.

If a doe enters estrus early, any buck that encounters her will chase her. Meanwhile some of his peers may still be seeking a hot doe while others are making scrapes or merely filling up on calories to keep up their strength. It would be incorrect to say that all or most bucks are in the chasing phase a week before peak breeding, or the seeking phase two weeks before. It changes from day to day and deer to deer.

When a doe is ready to “stand” for a buck they will often retreat to some secluded area, provided they’re not continually harassed by other rival suitors. There, they’ll remain together for a day or two until the deed is done. You might think this would be a quieter period in the woods but for every doe that’s ready, there are still more that aren’t, and are still being sought and courted.

The period after peak breeding, what many hunters refer to as post rut, can be slower. There are fewer deer and those left have been educated by a month or more of hunting pressure. It can also be a good time to shoot a mature buck. Those old boys that had been biding their time before peak rut are now re-doubling their efforts to find the last remaining hot does. That’s why many of the oldest deer are taken during the last week of firearms season. After that, deer activity really slows as the deer spend a few hours on their feet feeding and the rest of the day in bed. That sounds like a pretty good plan.

Bob Humphrey is a freelance writer and Registered Maine Guide who lives in Pownal. He can be reached at: bhunt@maine.rr.com