Coyote growth hindering whitetail deer population

Aside from hunters and speeding cars, whitetail deer have had little to fear in recent decades, especially in the Southeast.


Today, however, herds that once soared are shrinking -- and the secretive coyote might play a larger role than anyone imagined.

"Coyotes first showed up here in the '70s," said Charlie Killmaster, Georgia's state deer biologist. "They didn't do much in the '80s, but by the mid-1990s, they just exploded."

The rapid rise and continued expansion of a relatively new predator has spawned numerous studies to gauge their impact on deer populations.

"Last year, hunters killed 400,000 deer, and maybe 50,000 to 80,000 were hit by cars," Killmaster said. "As far as how many were killed by coyotes, we aren't sure."

Coyotes rarely kill adult deer, but there is growing evidence that their affinity for newborn fawns, which drop in May and June, is affecting herd numbers.

"What makes this predator so successful is that they are opportunistic and can eat any number of things, like fruits and small mammals," he said. "Deer are really only a food source for one short period, which is fawning season."

Studies in several Southeastern states show coyote-fawn predation is significant, especially in South Carolina, where the deer population fell by 36 percent from 1997 to 2006.

That year U.S. Forest Service research biologist John Kilgo launched a study at Savannah River Site in which five newborn fawns were tracked with radio transmitters. Coyotes ate four of them.

By 2008, Kilgo's group had monitored 60 fawns, of which 28 were killed by coyotes.

Kilgo said more data are needed to accurately define the relationship between the two species.

"The logical and first conclusion everyone jumps to when they hear these numbers is, we have to go kill some coyotes," he said. "But in fact, having hunters shoot them from deer stands or landowners removing handfuls of animals is not a solution. It's more a matter of learning how to live with them, because you can't get rid of them once they're here."

Last year, in an article in the Journal of Wildlife Management , Kilgo and other experts including South Carolina deer program leader Charles Ruth, U.S. Department of Agriculture biologist Scott Ray and University of Georgia deer research scientist Karl Miller collectively agreed the coyote issue warrants more attention than it has gotten.

The findings at SRS, they wrote, are similar to conclusions in other regions.

Two studies in Alabama, for example, found that coyotes kill huge numbers of fawns. On one tract, the ratio of fawns to adult females was measured at just 0.41.

After an intensive trapping program that removed 22 coyotes, the ratio almost tripled the following season to 1.20.

Although hard data are unavailable on the precise number of coyotes at SRS, "the important point is that the coyote population grew from zero in the early to mid-1980s into being well-established by 2000, and this growth was concurrent with the decline in deer fawn recruitment," the article said.

The impact of the coyote is important because deer and deer hunting are big business in the South, where hundreds of thousands of hunters spent billions of dollars on their pastime.

Killmaster said that just a few years ago, there were too many deer in Georgia, and rising numbers of deer-vehicle crashes led to more liberal bag limits and longer hunting seasons.

"Now, the deer population across the state is considerably down from where it was, but most of that was by design," he said. "We had about 1.4 million deer in 1997, the highest number ever, and we're down to about 904,000 today. We really want to be at about 1 million deer."

To sustain that goal wildlife agencies might need to include coyote kills along with car crashes and hunter harvest in future management decisions.

"Hunting is still the predominant cause of mortality for deer in the state, although we now have this new factor to contend with," Killmaster said.

Georgia biologists are halfway through a four-year study of coyotes and deer at state-owned Cedar Creek and B.F. Grant wildlife management areas, where deer survival rates are calculated as coyotes are trapped and removed.

"We want to see how coyote densities and deer densities interact," Killmaster said. "We'll be looking at numbers both pre- and post-coyote removal."

Other studies involve genetic analysis of coyote droppings to determine how many individual animals are present, he said.

A coyote advisory committee has been formed through North Carolina State University, and a former SRS scientist is involved in studies in northwestern Louisiana. Auburn University is conducting research and a study in south Georgia is scheduled to begin next year with participation from University of Florida.

"Very few of them have published yet, so a lot of them are still gathering data, like we are," Kilgo said. "We don't have a lot more information yet, but in the next year or two, I think we will know a lot more."