Deer Reproduction and Localized Management in Indiana

By Chad Stewart

It seems hard to imagine now, but there was a time when there were no deer in Indiana. Actually, that time was not long ago. The last reported deer was seen in 1893, and Indiana remained “deer-free” until 1934 when the Division of Fish and Game (now Division of Fish and Wildlife) reintroduced deer into southern Indiana. This reintroduction effort lasted for almost 9 years until 1942, releasing a total of 296 deer. By 1951, the herd was estimated at 5,000 animals and the first hunting season in 58 years was implemented. Hunters that year harvested almost 1,600 deer. Today, only 60 years since deer hunting returned to Indiana, the deer harvest exceeds 130,000 animals a year, and should be lauded as one of the major accomplishments of modern wildlife management. Unfortunately, their increasing numbers are causing conflict for many Indiana residents.

Deer are extremely productive animals. Deer can obtain sexual maturity at six to seven months of age or once they reach 80 pounds, which can easily be achieved living in fertile farmland habitat. Female deer often give birth to between 1 and 3 fawns, with older does more likely to give birth to 2 or 3 fawns than younger deer. Again, habitat plays a key role, and the highly nutritious diet of deer in Indiana favors increased reproduction. Female deer are capable of reproducing their entire lives; there is no age where their ovaries become inactive. Deer have few predators in Indiana. Their primary predator is man, and hunting or collisions with vehicles are the most likely reason a deer will die in Indiana. Other natural predators such as coyotes and bobcats, may prey
on smaller deer or sick deer, but their diets are largely composed of small mammals. Domestic dogs can and will run and kill deer, and may impact deer populations locally in certain areas, but do not appear to be significant factors at controlling deer at the statewide level. The ability for deer to reproduce early and late in life, have multiple offspring each year, and few natural predators, all within ideal habitat, lends itself to growing populations.

The DNR does not estimate deer populations across the state. Some states still estimate their total annual deer population using models supplied with biological data. These data include, but are not limited to, fawn sex ratio, fawn:doe ratio, buck recovery rate, adult sex ratio, etc. It’s arguable the cost to collect this data is not equal to the value or usefulness of the estimate. In modern deer management, knowing the actual number of deer is not as important as knowing how the deer herd is trending. Indiana uses variables including antlered harvest, deer/vehicle collisions, damage reports received, and various surveys to monitor population trends. Currently, those trends are all showing that the deer herd has steadily increased over the previous 10 years. With fewer hunters predicted in the forecast, it will become increasingly difficult to continue to manage Indiana’s deer herd in the next 20 years or so.

The DFW continues to liberalize deer hunting regulations in an effort to reduce Indiana’s deer population, but simply allowing more deer to be harvested will not translate into a lower deer population if such regulations are not liberally employed by the majority of landowners across Indiana’s vast rural landscape. Over 95% of Indiana is privately owned, and landowners havehistorically been more restrictive and selective in the harvest of deer than what the DFW legally allows. More emphasis on increased hunter access and antlerless deer harvest will be necessary to bring about herd reduction. Landowners wishing to maintain a deer herd balanced with respect to their surrounding habitat should strive for hunting success rates of 20% (H/E = 0.20; see Table 1) for firearm efforts and 10% for archery efforts. An “effort” is defined as one attempted day to harvest an antlerless deer, and the number of firearm efforts should be equal to 1/5 the amount of total permanent acreage. Since 1993, these rates have been successfully used by Indiana State Parks to bring about the recovery of certain palatable plant species. While these success rates have not been tested on private lands, they serve as a reasonable start for landowners.

Hunting on private lands is different because ownership parcels are smaller, hunting effort is usually spread out over the season, and landowners are likely more efficient hunting their own properties. One antlerless firearm effort can be replaced by 5 archery antlerless efforts if spacing throughout the property and season prove to be difficult. The calculation of the success rate should only include the harvest of antlerless deer, not antlered deer.  In order to implement these recommendations, it may be necessary for the landowner to increase the number of hunters currently allowed on the property. The DFW has initiated a Hunters Helping Farmers program whereby deer hunters interested in helping landowners harvest antlerless deer during the deer hunting season can register. This list can be attained through your local district biologist, who can help make recommendations on hunting pressure and managing deer conflicts on your property.

When managed properly, deer can provide a valuable recreational and aesthetic component to any landscape. Like most things, however, when they become abundant, they can provide conflicts and negatively affect their surroundings. It is everyone’s mission to help keep deer as a revered, and not reviled, species on the Indiana landscape, but this will require sacrifices by both landowners and hunters to achieve.

Chad Stewart is a deer biologist with the Indiana Division of Fish and Wildlife.