Deer Excursions: Why Bucks Leave Their Home Range
Like many readers, I use exponentially more sick leave during the fall than any other time of the year. Why this happens is simple: I’m just too stubborn to give up on a buck. Once locked in on a particular buck, my hours on stand increase, and more times than I care to admit, I fail to even see that same deer again. Can you relate? Whether it’s seeing a buck on stand or on a trail-camera picture, stubbornness can have its benefits…
But, is there a reason why you failed to even get another glimpse of a “shooter” buck? One camera study in Missouri showed as many as 40 percent of bucks (2½ years old and older) left their established home range in the fall and returned either later in the year or the following season. The researcher termed this behavior as an “excursion” and suggested it may occur on a yearly basis. Obviously, the trail cameras were not photographing all the bucks in the area, so were these buck excursions a random occurrence or a seasonal routine, and why?
Biologists know many rutting bucks can have two separate core areas within their home range. It’s not uncommon for these bucks to bounce back and forth between these core areas. Although some writers have termed this behavior as excursions within their home range, this is incorrect. Excursions are trips where deer completely exit their home range and then return.
Obviously, many hunters can relate to finding a good buck only to have him leave, but the overriding question is: Was the buck present on the property the whole season, or did you not hunt hard enough? Worse yet, did you fall victim to your own aggressiveness and overhunt the area?
Although these questions are hard to answer, biologists know some bucks will put up with all kinds of hunting pressure while other bucks will vacate the area as soon as they sense even one hunter. In addition to hunting pressure and the personalities of individual bucks, quality habitat may trump everything. For example, why would you leave an area that had ample food, water, and cover?
One of the first studies to address excursions with radio-telemetry equipment was conducted in Maryland. The researchers defined an excursion as, “When a deer leaves its home range and goes several miles, and then returns within a few days.” Although biologists first thought excursions were only undertaken during the rut by bucks, this study showed excursions were also made by does and could occur at any time of the year.
Another excursion study was conducted in Tennessee. The researchers followed 10 collared bucks and 10 collared does. Seven of the bucks made excursions during the rutting time period: one during the pre-rut, four during the rut, and two in the post-rut. This evidence may answer why some of us see bucks during the rut that no one else in our hunting group has ever seen. Additionally, it may answer what happened to the shooter buck you thought you had patterned. As for the does, six of them took excursions in the pre-rut, rut, and post-rut time periods.
After reading and listening to these studies at the annual Southeast Deer Study Group meeting, I remember having a biological epiphany. The reason for the bucks and does taking excursions and leaving their home ranges in the spring (Maryland) and fall (Tennessee) was because the daylight hours per day (photoperiod) were relatively the same, only reversed. The same thing occurs with ruffed grouse when they drum in the spring to announce their territory and attract a mate. In the fall, many “confused” birds also drum. I was then corrected by Dr. Dave Samuel, who told me that these excursions seem to be during the rut and spring, but additional research has now shown excursions can take place throughout the year.
To prove his point further, Dr. Dave mentioned another excursion study with 13 collared bucks, aged 2½ years old and older, in Pennsylvania. Nine of these bucks made excursions between April and May. The average excursion was 2½ miles and lasted 22 hours. One buck was recorded traveling more than five miles. Other studies have shown these excursions may last up to two or three days. The one common denominator in all of this is the deer will return to their normal home range.
Okay, so why and what makes a deer exhibit an excursion? To date, biologists do not know. Maybe excursions have something to do with advertising social status within the herd, especially during the rutting time period. By roaming outside their familiar home range, bucks and does are more vulnerable, but they may be doing this to maximize their genetic potential during the rut.
As for springtime excursions, some deer might simply be looking for more favorable food. The problem is, many excursions occur after spring green-up, when ample supplies of food exist. Is there any correlation between deer living in poor habitats making more excursions than those living in better areas? Although you may think so, no connections have been made. And yes, better-quality habitat correlates to smaller core areas and home-range size.
C.J.’s Summary: Research has shown that age, sex, and food do not seem to have any correlation with excursions. Hunters must remember that not all deer exhibit excursions. Again, leaving an established home range is not the norm, yet a certain percentage of both sexes exhibit some short-term excursions during the year. Instead of beating yourself up over why “your” buck left the area, consider that he may have just taken an excursion for a day or two. The good news is, he’ll be back!