Study reveals moves of mature Pa. bucks

St. Marys, Pa. — Few hunters have the time or resources to conduct a full-scale study of seasonal travel and habitat use of mature bucks in their hunting areas. If such a study were possible, however, it could reveal some interesting data that could impact the decisions made in managing properties for mature bucks, or even suggest a different approach to hunting them.   

Fortunately, Andy Olson’s recent study was able to shed more light on this very issue. Olson, a Penn State and University of Georgia graduate, hails from St. Marys.

As part of his Master’s thesis for the University of Georgia, Olson captured 19 mature bucks on a 7,000-acre privately owned Elk County property, and equipped them with GPS collars to track their seasonal movement patterns over the course of a year.

Under the guidance of his adviser, nationally acclaimed Quality Deer Management deer biologist Karl Miller, Olson set out to accomplish something never done before.

“Hunters are very interested in big bucks and how they use a property,” said Olson. “Similar deer movement studies have been conducted in agricultural regions of Maryland and Oklahoma, and even the scrub brush of Texas, but never in the continuous hardwood forest of north-central Pennsylvania.

“I wanted to use this evolving GPS technology to learn more about mature buck movement in our state, where the population of older bucks is currently on the rise.”

After applying for a host of research permits from the Pennsylvania Game Commis­sion, Olson and a local deer-capture team used rocket nets, cage traps and dart guns to tranquilize and collar wild bucks age 3 and older at various stages of the year.

He then used the “Dynamic Brownian Bridge” system using GPS collars to calculate a movement variance index that charted habitat use vs. availability within the study area, as well as tracking exact buck locations at one-hour intervals during the off-season and at 15-minute intervals during hunting seasons from October through December.

Olson wanted to determine the bucks’ seasonal home range variance (where they spend 95 percent of their time) and their core areas (where they spend 50 percent of their time within that 95 percent home range), as well as track movements to preferred habitats/food sources during the year.

He also hoped to gain a deeper understanding of mature buck movement during pre-rut, peak-rut, and post-rut stages.

The results of his study revealed an average home range for mature bucks that fluctuated by season: fall – 900 acres; winter – 800 acres; spring – 717 acres; and summer – 415 acres.

Likewise, the core areas also varied: fall – 116 acres; winter – 115 acres; spring – 100 acres; and summer – 60 acres. These figures were similar in comparison to the studies conducted in other states.

“Home ranges shifted throughout the seasons with food availability,” Olson said. “A lot of time and money goes into food plots, and I wanted to see if they really worked.

My study showed that forest openings were extremely important to these bucks. In spring and summer, plots of clover, chicory and fescue grasses were primary food sources rich with protein.”

In the fall and winter, bucks shifted to mature timber areas where mast crops were prevalent, Olson noted, but he still witnessed movement back and forth from the mature timber stands to the food plots.

“This shows that creating a diversity of habitats – select and clear-cut timber stands, having mature stands harboring hard mast of acorns and beechnuts, as well as forest openings with deer-specific forage – will cover the yearly range of nutrition for mature bucks.”

Concerning rut movement, Olson used a previous Game Commission study to define the three stages of rut. According to that study, 80 percent of does are bred during November. Thus, he defined Oct. 1-31 as pre-rut, Nov. 1-30 as rut, and Dec. 1-31 as post-rut.

Olson’s study noted a simultaneous spike in both home range and movement variance during peak rut, with daytime movement increasing eight times as much during the rut as compared to pre-rut.

“During peak rut, it is absolute mayhem,” Olson explained. “The bucks are snaking everywhere looking for does to breed; but interestingly, they often stayed within their home ranges. Bucks did focus on different core areas within their home ranges but they never left their home ranges for a long period of time.”

The core area preferences shifted almost weekly November. Bucks moved almost constantly the first week, corroborating a “seek-and-chase” phase mentality. During the second week, they concentrated on thick areas, but still moved. Then during the latter two weeks of November, bucks returned to food plots.

“It’s tough to say if they hit the plots to feed and recover or simply because does were concentrated in these areas. One particular buck did not leave a hill overlooking a turnip field for nearly two weeks, even though it was not his core area any other time of year.”

Despite the seasonal composite movement tendencies Olson’s study revealed, the date showed no patterns by age class, no evidence of an “October lull,” “lockdown phase,” or bucks going “nocturnal” during any stage of the rut. However, it is important to remember that this was one isolated, diversely forested study area, and every buck in the state is different.

“The big take away from a hunting perspective is that bucks are complete individuals,” Olson said. “In my opinion, bucks have different personalities and it is sometimes best to pursue multiple bucks in different core areas, rather than just focus on one because it’s always changing during the rut.

“If you can’t catch them in their predictable early October feeding patterns, then the first two weeks of November are prime for peak daytime movement, he added.

“Focus on the best areas and don’t be afraid to switch things up. Having a diverse habitat is likely to keep mature bucks within their home ranges, and it’s just a matter of timing and pinpointing them at the right location.”

Olson, who recently completed his Master’s Degree in Wildlife Management and Ecology welcomes any questions regarding his research. He may be reached at aolson20@uga.edu.

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