Wisconsin Department of Natural Resources
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Yearling Buck Percentage
   The yearling buck percentage is estimated from aging data of harvested bucks and is used as an input into the formula for annual deer herd abundance estimation. Here, yearlings are defined as 1.5 year old deer. Yearling buck percentages were summarized using groups of county deer management units. County deer management units were grouped based on location, habitat characteristics, and deer demography. For additional Information….
The yearling buck percentage is an input into the formula that is used to estimate the deer population size by deer management unit (DMU). In the formula, the yearling buck percent is used to approximate the buck mortality rate and the buck to doe ratio which are two components needed for the calculation of the pre-hunt population estimate. Yearling buck percent is closely aligned with hunting pressure and where there is a higher harvest of bucks there is typically a higher yearling buck percentage.
Collection and analysis methods
Aging data of the harvested antlered deer is needed to estimate yearling buck percent. With the move to electronic registration, aging of harvested deer is primarily accomplished by DNR staff in cooperation with deer processors receiving harvested deer from hunters. At the deer processors, deer are aged based on teeth wear and replacement patterns and it is straightforward to age yearlings (1.5 years old) from older adults (>2.5 years old). In addition, aging data are collected from deer submitted for chronic wasting disease (CWD) sampling. Yearling buck percentage is a calculation of the number of yearling bucks (1.5 years old) divided by the total number of adult bucks (>= 1.5 years old). Due to sampling limitations, yearling buck percentages are estimated annually for 9 county groupings.
Using the metric
The annual estimate of yearling buck percent is shown by county grouping because of low number of aging samples at the DMU level. The 3-year average shows the trend in yearling buck percent. Yearling buck percentage is primarily used as an input into the formula for estimation of herd size at the DMU level. Yearling buck percentage correlates to hunting pressure on antlered deer with higher yearling buck percentages usually indicating higher hunting pressure.
Limitations and precautions
The number of bucks aged is variable across DMUs and it is difficult to get very large sample sizes in some areas.
Future needs
Continued work is needed to maintain and increase aging samples of harvested deer now that electronic registration is in place.
Additional background materials related to this metric
The white-tailed deer population status report is available for viewing on the Wisconsin DNR website dnr.wi.gov keyword “wildlife reports” and there is reference to the use of the yearling buck percentage in the deer population estimates.

Yearling Buck Percentage
Average Yearling Buck Percent: 48.68 Average Yearling Buck Percent: 51.75 Average Yearling Buck Percent: 52.83 Average Yearling Buck Percent: 47.60 Average Yearling Buck Percent: 54.04 Average Yearling Buck Percent: 56.65 Average Yearling Buck Percent: 67.24 Average Yearling Buck Percent: 66.53 Average Yearling Buck Percent: 64.01 Average Yearling Buck Percent: 54.01 Average Yearling Buck Percent: 62.79 Average Yearling Buck Percent: 63.92 Average Yearling Buck Percent: 61.79 Average Yearling Buck Percent: 54.26 Average Yearling Buck Percent: 56.5 Average Yearling Buck Percent: 60.03 Average Yearling Buck Percent: 64.35
For questions on this deer metric data contact:
Dan Storm 715-401-2715 DanielJ.Storm@wisconsin.gov
Jeff Pritzl 920-366-3450 Jeffrey.Pritzl@wisconsin.gov