Dept. Forestry and Natural Resources
715 W. State Street
W. Lafayette, IN 47907
(765) 494-3590
FAX: (765) 494-9461

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Management Implications

Crop depredation by wildlife is a substantial concern to agricultural producers in northcentral Indiana. Although our field surveys indicated that most fields incurred only light to moderate damage, fields exhibited a high variance in levels of depredation. For example, we found no wildlife damage in 11 of 160 surveyed fields; conversely, we recorded a maximum of 162,453 damaged plants in one soybean field and 8,357 damaged plants in one corn field. The potential for severe wildlife damage to field crops varies greatly and depends on several factors including animal densities across habitat mosaics, field characteristics (size and proportion of edges adjacent to woodlands), and landscape-level habitat features (e.g., % woodland in the landscape surrounding those fields).

We recorded a high level of raccoon damage to corn relative to previous research; raccoons were the source of 87% of observed depredation events. A relatively high population of raccoons in the study area is the most likely reason behind our observations. Throughout much of the Midwest, raccoon populations have increased over the past 100 years, and are currently at or near record population levels in Indiana (Plowman 2004). One reason for the increase in raccoon abundance may be the conversion of native forest and prairie to agriculture (Page et al. 2001). Declines in trapping effort due to decreases in pelt prices over the last 15-20 years also are a likely contributing factor (Gehrt et al. 2002). Differences in depredation levels by raccoons between our study and previous studies (e.g. Kelley et al. 1982) may have been caused by regional differences in raccoon population numbers or the misidentification of raccoon damage as deer damage in previous studies. Based on visual observations of several fields using night vision, we are confident that we correctly identified wildlife damage. Preliminary research suggests that the density of local raccoon populations is positively related to the amount of damage to field corn caused by raccoons. Densities of raccoons were very high in our study area (X¯ = 0.6 raccoons/acre of forest; J. C. Beasley, unpublished data). For example, six individual raccoons were captured and marked in a single 10-acre woodland. Although this research is ongoing, it strongly supports the premise that local population control should decrease crop damage, at least in the short term. The immigration rate of new raccoons into an area likely is dependent upon the landscape configuration and surrounding raccoon population characteristics (e.g., density, sex ratio), which should dictate the length of time control efforts would be effective.

Proper identification of the species responsible for crop damage is vitally important so that landowners can implement proper management strategies. Furthermore, accurate assessments of wildlife damage by farmers are important because those experiencing damage may be less likely to manage for wildlife on their property (Conover 1998). Moreover, rules governing lethal control differ for deer, raccoon and groundhogs. For groundhogs, there are no limits on control in Indiana. Raccoons causing damage outside of regulated seasons can be removed in Indiana (trapped and relocated, or killed in a lawful manner) without a permit, although a conservation officer must be notified within 72 hours (312 IAC 9-3-15). Control of deer outside of the established hunting season requires a Deer Control Permit issued by the Indiana Department of Natural Resources through a District Wildlife Biologist; a minimum of $500 damage is required. Ultimately, the proper identification of the species causing damage to agricultural crops will dictate the proper management actions and the tools available to landowners to reduce such damage if they so chose.