Crop Raiders: The Most Notorious Munchers

Purdue University researchers who set up cameras in fields to catch wild animals in the act of gobbling up crops found that deer and raccoons -- not wild turkeys, as many farmers believe -- are the greediest crop-raiders.

After two years of field work, the Purdue team vindicated turkeys by showing that deer and raccoons caused 95 percent of the damage in the fields surveyed. Squirrels, groundhogs and other species, but not turkeys, inflicted the remaining damage.

The researchers staked out fields, using infrared cameras during their nighttime surveillance to catch the animals in action.

Those cameras revealed largely nocturnal deer and raccoons gorging in the darkness, their mouths stuffed with leaves, soybeans or corn, said Gene Rhodes, a Purdue professor of wildlife ecology.

Many farmers have long believed that turkeys, which are active during daylight hours and feed in flocks, were the critters eating and damaging their crops.

But during the two growing seasons surveyed, not a single incident of crop damage by turkeys was found. Because the plump birds arrived at the "crime scene'' hours after night-feeding deer and raccoons had fled, they were a victim of guilt by association.

"Turkeys are a highly visible species and sometimes it's hard to match perception with reality,'' Rhodes said in an interview Thursday. "When you see them in the fields sometimes you assume they're the ones doing the damage.''

He said turkeys' impact on farm fields is small, with the birds mainly snapping up waste grain and insects.

Rhodes and his cohort, Purdue Extension wildlife specialist Brian MacGowan, hope their ongoing work can pinpoint the unique signature of crop damage caused by deer, raccoons and other animals to help farmers determine which species is to blame.

Eventually, their research might lead to wildlife educational programs for farmers and landowners and more effective ways of combatting wildlife-related crop losses that exceed more $4.5 billion per year in the United States.

Among the 529 north-central Indiana farmers participating in the Purdue study, 82 percent reported some wildlife damage to crops -- such as plants shorn of leaves, toppled or stripped of bean pods or ears of corn.

MacGowan, who spent many nights in fields monitoring wildlife activity, recalls the noise several raccoons made raiding one cornfield, climbing and toppling corn plants.

"There were times when they were all around me, some of them I couldn't even see but just from the noises of the plants being knocked over I could tell where they were,'' he said.

As part of the research, the Purdue team outfitted deer, raccoons and turkeys with transmitters to track their movements. That information is being plotted, along with crop damage estimates, on a detailed digital map spanning 450 square miles.

"We'll ultimately be able to put those two things together and figure out how much time turkeys, deer and raccoons spend in fields, relative to how much damage occurs,'' Rhodes said. "We hope to determine if there are certain configurations of the landscape or the fields that lead to more or less damage.''

The research was supported in part by the National Wild Turkey Federation, which supports scientific studies of the management of wild turkey, which in recent years have become increasingly common in the nation's agricultural areas.