Understanding deer movement in farm country

October 23, 2012

Up until recently, a lot about what we knew on buck movements was simply based on observations. You’d see a particular buck here one day, and two days later you would spot him a mile away. Such observations were very superficial, but it was all we had.

However, today we have new technology that allows researchers to pinpoint the exact, and I mean the exact, location of bucks, right down to a few square yards. GPS radio collars and satellites have opened up a whole new world relative to knowing where bucks move, how far they go, and how often they do so. The simple truth is that when you put GPS radio collars on deer, you literally know exactly where they are every second of the day. That is what North Carolina State University researchers did while studying deer movements at Chesapeake Farms on the eastern shore of Maryland.

The eastern shore of Maryland is farm country, with mixed forests and lots of agricultural crops. The 3,300-acre Chesapeake Farms is a prime example of such farms and is composed of forests (50 percent), crops and food plots (30 percent) and grass (20 percent). It is a wildlife haven where the latest agricultural and wildlife management practices are used to demonstrate how they can work together. There are deer food plots, hedgerows, marshes for waterfowl, seasonally flooded woodlands, woodlands, waterfowl feeding areas, and grassed waterways. Deer are hunted there and research on deer is ongoing.

We’ve always known that deer move more in open country than in forests. Now we know a lot more. The researchers at Chesapeake put GPS collars on 15 adult bucks and followed them in two pre-rut periods (Sept. 24 – Oct. 14 and Oct. 15 – Nov. 4), the rut (Nov. 5 – 20) and the post rut (Nov. 21 – Dec. 30). The bucks they followed were all mature; two were 3 ½ years old, five were 4 ½ years old, four were 5 ½ years old, and four were unknown but over 2 ½ years of age. They’ve been practicing quality deer management on the farm for several years, and they have good mature bucks to show for that effort.

Movement Findings

The average home range for these bucks was 896 acres, and surprisingly, it did not change significantly during any of the four periods. Researchers also calculated the core home range — the area where bucks spend 50 percent of their time. At the end of the summer, the bucks’ core home range was just 35 acres, simply because there were lots of crops for food and they could bed in nearby forest cover. As you might expect, that core home range expanded, growing to 115 acres during the rut.

But the Maryland researchers indicated that November core home ranges for bucks were often where the does bedded. Makes sense. In the rut the bucks want to be where the does are. This tells the hunter that if you want big bucks, then you need to be close to their core area where you can find them 50 percent of the time. Most of the year, such areas are where they bed and feed, but in the rut, feeding is out (at least for the bucks) because they only have one thing on their minds — does.

No one will be surprised to learn that bucks traveled further during the rut than any other period. In fact, their daily movement at that time was 2 ½ miles. The researchers also looked at various factors that could affect deer movement in farm country. They measured the distance between hourly movements for each buck, and found that higher temperatures curtailed buck movement, except in the rut. In general, though, bucks move more when it is cooler. No surprise. What we might not have known was that in the pre-rut, temperature affects movement more in the late afternoon than in the early morning. On hot days, in that early bow season, morning movements might be better than afternoon movements.

Moon phase movement was inconsistent, but there did appear to be increased movement in darker phases of the moon. In the rut, the Maryland study showed that time of day is a better predictor of movement than temperature. Bucks moved more in the mornings. So, getting to your tree stands without busting deer is a bit more challenging, meaning you need to be out there an hour before daylight to reduce the chance of that happening.

Texas Data

Texas research shows a bit of a different picture relative to buck movement. First, the average home range for mature bucks was 2,271 acres — much bigger than in Maryland, and that probably relates to food and cover. The Maryland site had lots of food plots and crops located near forests. In the rut, mature Texas bucks move over 7 miles a day, while Maryland farm bucks only moved 2 ½ miles a day.

Both Maryland and Texas bucks showed tremendous individual variation in how much they move. And other studies show the same thing for does. I cannot emphasize this enough. It’s hard to make a general statement about buck (and doe) movements anywhere in farm country simply because the individual variation is so large. Some old mature bucks move a lot, while others move very little. Some younger mature bucks move a lot, while others move very little. A few big bucks will cross roads a lot, but most do not cross roads very much.

The Maryland study also showed that bucks go on one-day (or less) excursions out of their home range. They just up and leave, in the pre-rut, rut and post-rut. In both Maryland and Texas, around 40 percent of the mature bucks took these one- to two-day excursions in the pre-rut. In Maryland, 58 percent of the mature bucks took these one- to two-day day excursions during the rut, but in Texas 100 percent of the mature bucks made such moves. Twenty percent of mature bucks in Maryland and Texas took these excursions in the post-rut. In Texas the bucks walked from one-half mile to as far as a mile and then returned within one or two days. In Maryland the bucks don’t move as far, but they also might stay a day or less, then head back home.

Interestingly, does take these excursions during the rut as well. Around half of the mature does in Pennsylvania and Maryland made such excursions during the rut. In fact, one doe in the Pennsylvania rut moved four miles, then returned. Obviously, there is something about these day trips that is related to breeding — bucks hunting does, or does hunting bucks.

Add this all up, the excursions plus the individual variation in buck movements, and you begin to understand why finding those big bucks is so hard, and so much fun. Have a great season!