Can Predators Threaten Iowa's Deer Herd?
October 04, 2010
Believe it or not, wolves, bears and even cougars have been reported in Iowa! Could they, or coyotes, ever pose a threat to our deer?
One IDNR biologist estimates there may be 10 or more cougars roaming in Iowa. Photo by Mark Werner
By Rich Patterson
On the wall of Bob Pratt's living room is the tanned hide of a 140-pound mountain lion. He shot it a few years back after a pack of dogs sent it scurrying up a tree.
Pratt, my old college roommate, has taught agricultural education for over 30 years in the tiny town of Nezperce, Idaho. Around his home are thousands of acres of crops, canyons, timber, and generally wild country. Mule and whitetail deer and herds of elk can be spotted on an evening drive. Mountain lions can find plenty of food and hiding places there, but in all his years living and hunting in lion country he's only seen a few. "There really aren't many of them, and they're elusive," he said.
Idaho big-game hunters have always had to cope with cougars and bears competing for their deer. Not so Iowa hunters: Until recently there were no big cats in our state. When Columbus made his famous voyage, cougars, bears, and wolves were common in what would become Iowa. They fed on large herds of deer, elk and other wildlife. Extirpated for years, cougars have moved back, and they aren't the only big predator that will cast a hungry eye on our numerous deer. Wolves are gradually spreading south in Minnesota. At least one probably crossed the state to be shot in Missouri, and odds are fairly high that more of the big canines will enter Iowa. Every once in a while a bear is sighted in northeast Iowa, and they, too, will probably become a little more common. The big question is the impact newly arrived predators will make on Iowa deer and deer hunting.
At one time, the cougar, also called mountain lion, was the most widely distributed large mammal in the New World. The big cats ranged from the Atlantic to the Pacific and from central Canada nearly all the way to the southern tip of South America. As our continent was settled, they didn't stand a chance across most of their range.
As the human population of the United States grew, farms were carved out of the wilderness. Back then, all predators were hated, and nearly every farmer kept a rifle close at hand and didn't lose an opportunity to shoot one. But the real threat to lion populations was the destruction of their food sources and hiding places. The wild savannas and wooded river valleys found in Iowa before settlement fell to axes and plows, and the once-abundant deer and elk were gone by the late 1800s. Predators that, if they were to live, needed concealment and an abundant supply of deer lost both, and thus disappeared. The last cougar was probably gone by the end of the 1860s - and no one expected them ever to return.
Times changed. Habitat altered yet again, and the lions responded. Following decades of loss, our state gradually is seeing some increase in prairies and woodlands, and the return of our massive deer population has been a wildlife phenomenon. By the 1980s, places to hide in and all the food they could ever want became available to the king-size felines once more.
Although lion sightings have been reported from time to time for years, they were either false alarms or reports of animals escaped from private zoos - but within the past decade, that began to change. County naturalists and Iowa Department of Natural Resources biologists started getting a few sighting reports that seemed credible. The proof of the pudding came when two wild cougars were shot. Another was killed when it collided with a car. The animals came from near the towns of Sioux Rapids and Harlan in western Iowa and Wayne County in south-central Iowa. None were zoo escapees. Where they came from is unknown, but many speculate that they spread out from the nearest known population in the Black Hills of South Dakota.
Wild lions have arrived. "We may have upwards of 10 animals roaming the state. I'm guessing that half are genuinely wild and the rest are escapees from private zoos," said IDNR furbearer biologist Ron Andrews. That's not many animals. Ten cougars in our state would average out to one per 10 counties.
There are many more captive cougars in Iowa than wild ones. "It's a difficult paperwork process through the Department of Agriculture to legally acquire and keep a cougar, and right now the only legal animals come from South America," continued Andrews. Estimates of captive cougar numbers in Iowa range from about 100 to 500. "I think it's closer to the smaller number," he said.
Andrews, like all wildlife biologists, is wary of news reports of cougar sightings. "Whenever a newspaper or television reporter does a story of a cougar sighting we get dozens of calls from people claiming to have seen one. Nearly all turn out to be dogs, big house cats, or figments of the imagination," he said.
A track sighting near Kirkwood College in Cedar Rapids a few years ago is a good example. Someone sighted big tracks in the snow, claimed they were made by a mountain lion, and called the media. Although an Iowa DNR conservationist examined the tracks and identified them as from a dog, the media reported the possible occurrence of a cougar. No confirmed sightings were ever recorded in the area, yet many people firmly believe there are cougars near Cedar Rapids.
Some sightings may be legitimate. "Unlike Idaho, Iowa terrain and vegetation is pretty open. Especially after the crops come in, frost kills back weeds and snow falls, it would be tough for a mountain lion to hide here. And with all the people out deer hunting there are good odds that if a cougar is around someone will see it," said Willie Suchy, the IDNR deer biologist.
Although some hunters will probably spot an elusive cougar this fall, because there are so few of them scattered over 56,000 square miles, the odds that any individual hunter will see one are about as likely as being hit by lightning.
Questions remain. Will the cats increase in numbers? And what impact will they have on deer and deer hunting?
Cougars are efficient killers. Unlike wolves that hunt in packs and use complicated teamwork to kill prey, lions are solitary. They wait alone to ambush their prey, and deer rate high on their menu preference.
Even though a big cougar might eat a deer a week or so, there are hundreds of thousands of deer in the state and only a few cougars. "I don't think they'll have much impact on the deer population or deer hunting," said Suchy. Some people speculate that cougars might effectively curb overabundant deer numbers in some of Iowa's urban areas. That's not likely. Cougars don't like living in cities, and the tolerance of people to big cats in suburbia will probably be low. Also
, a few cougars simply don't eat enough deer to trim expanding urban herds.
Cougars aren't the only predators that enjoy venison. Unlike cats, which essentially only eat meat, bears are omnivores that enjoy berries, carrion, roots, garbage and meat. They aren't as efficient at killing deer as cougars and mostly take an occasional fawn.
There is no reproducing bear population in Iowa. Every few years there's a confirmed bear sighting in the state, usually in Allamakee or Clayton Counties. Each sighting is likely a young male straying from its Minnesota or Wisconsin home. Male bears tend to range widely, but females stay close to home. For that reason bear populations tend to expand slowly.
North American black bear populations are thriving. Thirty years ago no one would have imagined that bruins would live in suburbia, but they are becoming increasingly common in New Jersey, close to New York City and near other urban areas. Iowa bears and bear sightings may increase over time as populations grow in nearby Wisconsin and Minnesota. We may eventually have a limited bear population, but it's hard to image that they'll make any impact on deer numbers.
The expansion of wolf populations has been another wildlife phenomenon.
Just a couple of decades ago a few wolf packs lived in northern Minnesota. They've now spread to Wisconsin and Michigan, and are sighted from time to time well south of the Twin Cities. There's no doubt that wolves are expanding their Midwest range, and a pack or two might come down the wooded corridor along the Mississippi River and find Iowa to their liking.
Wolves are highly intelligent and effective predators that hunt in packs. They love deer and eat plenty of them. But they're not likely to affect Iowa's deer herd. Consider the case of Minnesota. "We have a record number of wolves in Minnesota but the deer herd is thriving and hunting seems to get better each year," said Duluth wildlife expert and author Mike Furtman.
According to biologist Suchy, wolf numbers can attain fairly high densities and seem to respond to prey levels. They have more pups when food is abundant and fewer when prey is scarce. Essentially, the number of deer has more impact on the population of wolves than vice versa. If wolves were to reduce prey abundance greatly, they'd doom themselves at least to hunger and perhaps to starvation. Wolf packs cover a large territory. They are animals of large expanses of wild land, and such swaths of wilderness are so few in Iowa that it's unlikely that we'll ever have more than a token wolf population here.
OTHER DEER PREDATORS
Cougars, bears, and wolves aren't the only animals that occasionally kill a deer. Bobcats and coyotes won't pass up a venison meal, but they likely only catch an occasional fawn. Their impact on deer numbers is not significant.
Coyotes have been common throughout Iowa for decades. They live on farms, in woodlots and marshes, and even in our large cities. Coyotes mostly prey on mice, rabbits, and other small animals; they also love grasshoppers and fruit. In town they don't hesitate to forage in garbage cans. Since coyotes have been common in the state during the years when the deer population greatly increased, they can't be having much of an impact on numbers.
Bobcats were never completely eliminated from Iowa, and for many years a small number of them hung on along the Mississippi River bluffs and in the grasslands of southern Iowa. For unknown reasons, they're now increasing and expanding their range and are now documented as present in counties scattered across the state.
Unlike coyotes, they confine their diet solely to meat; like coyotes, they mostly prey on small animals. Although a bobcat may occasionally snatch a fawn, the small cats don't have much impact on deer populations.
PREDATOR LEGAL STATUS
Cougars and bears have an unusual legal non-status in Iowa. Because neither is listed in the state code, shooting them is legal. That's not the case with wolves, which are listed in the state code and are also federally protected under the Endangered Species Act. State furbearer biologist Ron Andrews says the IDNR would like to see cougars listed in the state code. The Legislature would need to add bears and cougars to the list of animals the IDNR can manage. "That way we could reduce indiscriminate shooting of cats and also have the legal right to recover a carcass for research," he said. "Doing that isn't a hot-button priority right now." But that could change if the animals become more numerous, and it's reasonable to expect that someday these big animals may come under IDNR regulation.
Deer biologist Willie Suchy feels that the political climate in a state as agricultural as Iowa will never allow big predators to be very abundant. Though Iowa law protects bobcats, coyotes and foxes are so abundant that there's an extended legal hunting season on them.
Deer hunters often have an inaccurate view of the impact of predators on deer abundance. It's seems logical that heavy predation by cougars and wolves would greatly reduce the number of bucks available for humans, but that may not be the case. Prior to settlement, Iowa had a healthy population of big predators and still had game everywhere. You can take an evening drive through the canyons and farm country near Bob Pratt's Idaho home and spot plenty of mule and whitetail deer and an occasional elk herd. Cougars, bears and newly arrived wolf packs work them over all year but there's still excellent hunting.
Before settlement it's likely that year-round hunting by cougars, bears, wolves and Native Americans kept deer and elk numbers in relative balance with what the land could support. Even though cougars, bears and wolves may become somewhat more abundant in our state, there will never be enough of them to influence hunting significantly. Human hunters and car collisions will control our deer herd.
Although the chance that any individual hunter will spot a cougar while on deer stand this fall is slim, almost certainly some hunters will see them. Odds are best in western and southern Iowa.
Sighting a cougar is an unforgettable thrill. Hunters can carry three tools with them to help positively identify their sighting. Most important is a small pair of binoculars. They shrink distance and make identification of an unknown animal much easier. Another useful tool: a small point-and-shoot type of camera filled with high-speed film. I seal my tiny camera in a Ziploc or other such plastic bag to keep it dry. Although I've never snapped a picture of an Iowa cougar, I have taken photos of all sorts of interesting things when I'm hunting.
A few hunters I know don't want to carry an expensive camera so they pack a cheap disposable one. Miniature cameras don't take up much space in a hip pack and only weigh a few ounces. Many have a telephoto lens. Clicking a photo of a suspected cougar will help the local conservation officer, sheriff or news reporter identify the animal.
The third tool that can help hunters identify an animal is a small carpenter's tape measure. Often it's very difficult to estimate distance or the size of an animal - scale can be a problem. For example, in poor light or at long distance it may be hard to tell a big house cat from a bobcat. When the animal stands in front of a fence or tree it's possible to note a branch, knot, or some other distinctive item at the animal's back. That makes it possible to walk to the spot after the animal has left and measure its height. By framing a possible mountain lion between two trees or rocks, it's possible to measure the distance afterwards and get an accurate idea of the length of the cat. Accurate measurements add credibility to sightings, and photographs provide airtight proof.
The return of cougars, bears and wolves to Iowa isn't likely to hurt our outstanding deer hunting. It will, however, add the thrill of possibly sighting an Iowa native that has been long gone but has now returned. The chance of seeing one adds zest to any trip afield.
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