Data-Driven Deer Management: What Biologists Learn After the Season Ends

By Shane Fuller (Wildlife Biologist), Bo Reid (Wildlife Biologist), and Jennifer Hunt (Content Writer)

For hunters, the end of hunting season might bring down time for relaxation with other hobbies after the hard work of the season, but for wildlife biologists, the work is just beginning. Once the season ends, biologists begin compiling harvest data and trying to get those last few jawbones from hunters. After data sheets and jawbones are compiled, the biologist will start to analyze the data and look at several factors such as age structure, lactation rates, weights, and antler measurements, which indicate the health of the deer population and whether management goals are being met.

Age structure is the most reliable indicator of harvest rates and population dynamic trends. Most management plans put age restrictions on bucks, so buck age is not a good indicator of the overall population. On the other hand, the age structure of harvested does should be an accurate representation of the age structure of the population. Higher percentages of harvested older age class does indicates that there are more older age class does in the population. Larger populations tend to have more does reaching older age classes, so if biologists are seeing high percentages of harvested does in those older age classes, they can conclude that the property can likely withstand higher doe harvests the following year. If harvested doe ages trend more toward younger age classes, hunters may need to back off doe harvest for a year or two. Near equal percentages of older and younger age class does indicates that the population is healthy and just needs to be maintained. Observation data can also play a factor in recommendations for the next year. This data allows for analysis of sex ratios, age structure, and fawn recruitment.

Lactation rates are also a very important indicator of herd health, as the percentage of does lactating gives us insight into the reproductive success of the population. Normal lactation rates can vary widely in different regions and areas. It is important to know the average lactation rate for the area prior to analyzing any lactation data. High lactation rates indicate that does are healthy and are raising healthy fawns. Low lactation rates indicate does might be in poor health and are not producing as many fawns. If lactation rates are low, it could indicate overpopulation and more does need to be harvested moving forward. On the contrary, high lactation rates indicate a healthy herd. High lactation rates and high reproductive output can indicate that doe harvest needs to be maintained to preserve the current population level.

Weight can be another good indicator of herd health. Heavier deer indicate healthier deer. Just like lactation, it is important to understand the average weights in the region and area to understand how the managed property compares. Once biologists have historical data for a property, it is very helpful to look at trends over time with weights.

Analyzing antler measurements for harvested bucks can be a great way to measure the success of a management plan. For most hunters, increasing antler size is the primary goal of a management program. Biologists use ages and antler measurements from harvested bucks to track antler size over time. Increases in antler size can also indicate an increase in herd health.

When it comes to deer management, all data is important data. Rather than look at each data point individually, biologists most often combine all data and look at it holistically. For instance, a low lactation rate alone might indicate more does need to be harvested, but a low lactation rate combined with a young age structure might indicate that fewer does need to be harvested. Deer management is both an art and a science, and working with a trained biologist can help hunters achieve goals and improve the deer herd on their property. AFM’s biologists are here to help hunters and landowners achieve their goals.