Bucks move more during the rut than any other time of year. The rut will peak at the same time every year in a given location. These two basic rules of the whitetail rut keep being reinforced by new scientific studies of bucks wearing GPS tracking collars. Yet, we continue to learn more. New studies are picking apart fine differences in buck behavior that can help hunters understand rut-brain bucks more than ever.
They are also helping rule out factors that many hunters still believe play a major role in deer movement, which is just as valuable as new information we didn’t know. I mean, what’s more enlightening than to learn your hunting strategy is based on false assumptions?
This summer, the University of Wisconsin-Madison and Wisconsin DNR formally published results from a buck movement study that was years in the works. Conducted in Southwest Wisconsin’s Dane, Iowa and Grant counties, it was part of the much bigger Southwest Wisconsin CWD, Deer and Predator Study. Out of 1,157 captured whitetails, the researchers peeled off 188 GPS-collared bucks for a separate study. They dug in to their activities in a short but intense period each year for four years: October 15 to December 1, which includes the peak of breeding in that area.
232 Buck Seasons
The 188 bucks included 104 yearlings, 64 that were 2½ years old, and 64 that were 3½ or older (One of those mature bucks is seen at the top of this page, in a photo captured by Wisconsin freelance writer Jerry Davis). Researchers tracked movements in four consecutive seasons, from 2017 to 2020. Bucks that died of CWD or other causes in the middle of a six-week study period were excluded from the buck movement study. Of the 188 bucks, 34 of them were monitored for more than one season, so in all, there were 232 “buck seasons” available for study.
The GPS collars were programmed to collect a location on each buck hourly during the six-week annual focus period. This gave the researchers total daily movement rates in meters per hour as well as daily area covered. Across the six-week period from October 15 to December 1 for four years, researchers saw some very consistent and predictable behaviors. As expected, buck movement rates and range sizes increased as the peak of breeding approached, and they topped out around November 4-8 each year before falling into post-rut levels by December (see the Movement Rate chart below).
“The day of the year is just overwhelming in terms of predicting buck movements,” said Dr. Dan Storm, Deer Research Scientist with Wisconsin DNR and a co-author of the study. “If you want to center your hunting effort when buck movement rates are highest, we can’t see anything you should look at but the date. It’s hugely strong and consistent.”
In Southwest Wisconsin, that reliable date for peak breeding is October 23 to November 12. Only a few factors had a significant relationship with buck movement during that time. They were buck age and time of day.
Buck Age Mattered
Bucks of all ages in the study moved more and covered more area as the rut peak approached, and then they all began moving less as the rut peak got further in the rearview mirror. Differences appeared when looking at the separate age classes of bucks.
Yearling bucks and those 3½ and older moved at very similar rates and with similar range sizes. However, 2½-year-olds had significantly higher hourly movement rates and range sizes than the younger or older bucks (left side of the chart below).
But where yearlings and mature bucks showed near-identical average hourly movement rates throughout the rut, mature bucks showed higher variance in those rates (right side of the chart above). In other words, yearling movement rates remained consistent over short periods, while mature bucks varied more often between low and high rates of movement. Can you guess why that might be?
If you said “tending,” collect a prize. Yes, these mature bucks are more likely to have the knowledge, experience and dominance to find and defend estrus does for several hours – known as “tending” – until that doe is ready to stand for breeding. In fact, collar data from some individual bucks showed what appeared to be tending events. See “Zoom In On Tending” below for more about this.
To summarize what all this means, yearling bucks appear to be a little more restrained than 2½-year-olds in their searching for breeding opportunities. Yes, yearling bucks successfully breed does, but it is usually in the peak of breeding when the most estrus does are available and mature bucks just can’t defend them all. Meanwhile, 2½-year-old bucks are going all out in their search for social experiences. Thus, their daily movement rates and range size are high and consistent, and they are likely the most visible age class to hunters.
“If there are two weeks when the odds favor an all-day sit more than any other time of the season, it’s these two.”
Now more experienced in their searching techniques, mature bucks have to cover less ground to find breeding opportunities. And they are physically big enough and dominant enough to bump younger or less aggressive bucks off receptive does. It’s why most successful breeders are 3½ or older even though younger bucks are also successful.
“Our suspicion is that 2½-year-olds on average have greater movement rates than 3½ because they’re less successful, they’re not tending as much,” said Dan. “A hunter might imagine that what they see is representative of what’s out there, but our data suggests 2½-year-olds are more likely to be seen, and older bucks are more likely to be hunkered down with a doe for part of that time.”
Time of Day Mattered
The other big factor that had a significant relationship to buck movement throughout the entire six-week rut phase was time of day. Repeated measurements show deer move most around dawn and dusk, and these 188 bucks behaved like normal deer.
The chart below shows daily movement rate averaged for each of the six-week study periods by buck age class. In each, there is an obvious U-shaped curve in the middle of each weekly average. That curve is what you see when you graph every major movement study of whitetails in the majority of their range. You get a peak in movement around sunrise, a slump in movement in the middle of the day (the bottom of the U), and a peak in movement around sunset.
That said, there are some interesting trends to note in the charts. First, of use to a hunter is that mid-day movement was significantly higher for all buck ages in the third and fourth weeks (October 29 to November 11) than in the two previous or two following weeks: 50 to 100 meters per hour more! Mid-day movement during these two weeks is still not equal to or higher than early and late daylight movement, not even in the weeks with the lowest dawn and dusk peaks. But, if there are two weeks when the odds favor an all-day sit more than any other time of the season, it’s these two. These are the two weeks of peak breeding, and though the calendar dates are likely different in your location, you should know the two hottest rut weeks where you hunt.
“You’re still more likely to see bucks moving on the evening of October 15 than you are at noon on November 4.”
“If you’re planning to hunt when you’re going to have the most bucks running around, that middle part of the day still sees a big drop in the movement even during the peak of the rut,” said Dan. “You’re still more likely to see bucks moving on the evening of October 15 than you are at noon on November 4.”
Second, nocturnal movement was also highest in those two prime weeks, 3 and 4. However, dawn and dusk still held their ground and are still visible as peaks of movement – with a slight exception. Look at the blue line for 3½-plus bucks in those weeks. In those two weeks, these mature bucks flirted dangerously with being officially designated as “nocturnal” animals. Week 4 (November 5-11) is when they came closest.
Recall, though, that these are the two weeks when all bucks are moving more overall – in each respective period of the day – than any of the other 50 weeks of the year. At night, at dawn, at mid-day, and at dusk, these bucks were setting annual step-count records. Whew! It was close, but we can continue to call whitetails crepuscular (dawn and dusk movers) even during the peak rut.
Bucks Ignored Temperature
My condolences to cold-front hunters, but the Wisconsin rut study supported patterns seen in many other buck movement studies: temperature did not play a significant role. The researchers collected daily minimum and maximum temperatures from the National Centers for Environmental Information, which operates a weather station located within the study area. Fluctuations in temperature did not shake buck-movement trends that reappeared at the same time, across the same six weeks, for four years straight. Tattoo it on the inside of your forearm: It’s the rut, not cold fronts!
Bucks Ignored Opening Weekend of Firearms Season
This finding may surprise hunters who think that the sudden arrival of heavy hunting pressure depresses deer movement. At least as far as rut-related buck movements in this Wisconsin study, it did not.
In this area, opening weekend of firearms season arrives after the peak of the rut on the weekend before Thanksgiving. Though the actual dates of opening weekend changed a little, it did not significantly disrupt trends seen over all four years of the study. Buck movement begins to decline after peak rut, but the placement of opening weekend did not alter this declining trend by accelerating the decline, altering day/night movement patterns, or causing any other measurable change.
Wisconsin’s firearms season opens the Saturday before Thanksgiving. The latest date it can possibly open is November 23. Then it opens earlier every year until it is on November 17, and the next year it goes back to the 23rd. This research suggests that earlier dates are going to be better because buck movement is declining slowly in this post-rut phase.
“Bucks are not necessarily able to have exclusive use of a doe without competition for very long. A buck could be tending a doe and still have movement rates that are not crazy low.”
“That movement manifests in our buck harvest,” said Dan. “Buck harvest is higher when opening day is earlier. That pattern has been apparent for a long time, and we assumed it was because of buck movement. This study confirms it.”
This year, opening day is November 22, and it will be on November 21 next year. It will open earlier until it’s the 17th again in 2029 (a leap year in 2028 causes opening day to skip the 19th and land on the 18th). Hang in there, Wisconsin hunters! Buck movement on opening day will be a little better each year for the next four years!
Bucks Ignored The Year
The same pattern of increasing and decreasing buck movement around the peak of breeding was seen each of the four years of study. The increases and decreases even aligned around the same days of the year. This reinforces a notion seen in many other studies: The rut is going to peak around the same time of year at any given location regardless of weather, moon phase, hunting pressure or other factors. You just can’t stop a doe from coming into estrus when the local time is right, and you can’t stop a buck from being interested in her.
Zoom in on Tending
The chart below shows three years of movement rate for the same individual buck. As a 3½-year-old, this buck’s movement rate dropped from over 300 meters per hour to 50 on November 7, then back to over 400 meters per hour the next day – an apparent tending event. I was curious how many other events like this could be seen in the data, and how common they were. Unfortunately, not many.
“I had hoped that we could, but we weren’t able to identify tending events to our satisfaction to count them,” said Dan. “That one you see in the graph was by far the most obvious one, so most tending might not show up when movement is summarized in 24-hour periods. Bucks are not necessarily able to have exclusive use of a doe without competition for very long. Settling in for the long haul may not be all that common.”
To illustrate this, Dan told of a situation where two collared bucks were located near each other. One appeared to be holding close as if tending a doe. The second buck then appeared to bump the first from the location, and the first continued to return to the area as if trying to recapture the doe.
“If you develop the idea that tending is 24 hours, it can mislead you,” said Dan. “Most tending might not show up in a study like this, or to a hunter. A buck could be tending a doe and still have movement rates that are not crazy low.”
That’s good news for hunters during the rut, and it reflects what other experts have said about tending: It does not mean a buck vanishes for days. As wildlife photographer Tes Randle Jolly once told me: “Truth is, it’s quite a feat for a buck to maintain possession of a doe.”
Just Go Hunting
When science repeats itself, it feels as good as when your arrows or bullets stack in a tight group at the range. The new Wisconsin study reinforces other study findings. One, bucks move more during the rut than at any time of year. Two, the rut will be at the same every year in a given location. Three, even during the rut, bucks move most around sunrise and sunset. Four, not much is going to change One, Two and Three.
When it’s the usual time for the peak of rut activity where you hunt, just go hunting!