Iowa Coyotes: Inside the Numbers

I hadn’t felt the cold wind sting my face in quite some time like it did that February day this last winter. My calling partner Mark and I joked that we must be the only foolhardy pair of coyote hunters actually trying to coax a coyote to us in the whole state in weather like that. The 35 mph gusts were dumping wind chill temperatures well below zero and making the skin on our faces actually hurt. Still, after several unsuccessful calling attempts, we pressed on into the afternoon in hopes of success.

Finally on the fourth stand, we went into a little spot that a farmer had called me about a week or two earlier wanting a little help. He’d had some coyotes killing a few of his sheep and wondered if I could come try and call them. So I said to Mark that we’d try and help him out. We set up along a brushy fence line that let us overlook some timbered draws to the North of the sheep pasture, where I suspected these coyotes may be spending their time during the day. I started off with distress cries and used three different mouth calls just trying to make sure I had enough volume to reach a set of ears. Man that wind was ripping!

After about ten minutes, I saw what I thought might be a fox cresting a little rise along the fence line coming towards us. Its reddish color in the sun fooled my eyes until I raised the binoculars and confirmed a nice red color phased coyote. She was coming slow, perhaps a little reluctant to venture up the hill, further exposing herself to the brutal wind, but a little coaxing brought her to 65 yards away, close enough. After a little squeaking to get her to stop, I sent a lead pill her way in a 22.250 prescription and the hard, cold day of calling was instantly worth all the effort!

Whether this particular coyote had been one of the culprits of sheep depredation or not, I’ll never know? All I did know was that it held up in the same section as this flock and responded nicely to the sound of prey distress. I ended up taking three other coyotes out of this coyote rich area this winter, but she was the only one in the same section of land as the farmer’s sheep. Since that time, the owner has lost a couple more of his ewes, his neighbor lost several lambs this Spring, and the farmer to the North suspected coyotes of killing two new born calves. More work needs done.

My Grandfather farmed all his life and owned sheep and cattle along the way. A longtime coyote hunter himself, he always claimed that once a coyote or pack of wild dogs got a taste of sheep blood, they wouldn’t stop. I believe he was right in his assessment but it all got me thinking about how damaging coyotes actually are to livestock and other game species here in Iowa. Actual facts about their population and the highs and lows in their numbers over the years are hard to pin down. So what are the driving factors that determine coyote populations here and what are the reasons they seem to vary from year to year? Let’s delve a little deeper.

Population

There are several ways to get estimates on coyote population trends over the state. One is the DNR’s bow-hunter survey. Statewide each year, certain bow hunters are selected to participate in a survey of their observations while hunting. They document sightings of different species while they are hunting and report the number of hours they sat in the stand. Nine regions of the state are segmented for a more detailed look at area specific population dynamics. Iowa’s DNR then combines all of the hunter’s data to note the number of observations per 1,000 hours of hunting. From this information, the DNR is able to calculate a rise and fall in population numbers from year to year for different species. In it’s eighth year, the bow-hunter survey has gained valuable data for population estimations.

For the coyote, population trends have remained fairly steady since 2004. Some rise and fall is easily seen from year to year especially in certain areas of the state. For example, in the fall of 2010, a rise in coyote sightings took place in every one of the nine divided regions of the state, indicating coyotes may have had a population increase from the year before statewide. In region 7 alone, located in the Southwest corner of the state, the count more than doubled from the year before resulting in near 50 sightings per 1,000 hours of observation.

Another way of getting an idea of population swings here in the state is through fur dealer report numbers. According to Iowa Code, every fur dealer must report the number of raw furs purchased from Iowa trappers and hunters by May 15 of each year. While the report numbers aren’t an absolute determining resolution to the answer either, it is another source to view as a snapshot look at the coyote and other furbearer species across the state. The total harvest for the 2010-11season was 8,089, up significantly from the previous year’s harvest of 2,501. This report as well shows a fairly large rise in numbers. All indications show a very healthy coyote population currently.

There are variables to be considered in this data however. There are considerably more coyote hunters than coyote trappers across the state, so data is broken down into coyotes sold by each method of harvest. Roughly 75% of the 2010-2011 numbers where taken by hunters. Generally speaking, a winter with more snowfall assists the vast majority of coyote hunters with larger harvest numbers and so a winter with less snowfall may be reflected with lower report numbers for the given year. That being said, the record snowy winter of 2009-2010 made low report numbers probable. The vast amount of snowfall that year made it difficult for hunters to gain access to their quarry. Weather plays an important role and is certainly a factor in report numbers.

Another factor is the fur market. Obviously, when the fur price is high, there are more people out hunting and trapping and more time is spent in the field so more coyotes are taken to the fur buyer. In recent years, with the price of a coyote pelt being extremely low here in the Midwest, some hunters simply did not sell their occasional furs. Some viewed it not worth their effort. Others stopped hunting as much because of high gas prices and low fur values.

Disease

It’s been said that if the Earth is taken over by some sort of apocalypse than only the three C’s will survive, cockroaches, crows and coyotes. Coyotes have long been targeted in efforts of complete eradication across the U.S for decades. Governments have used methods such as government trapping, aerial hunting, bounties and even poison control to try and eliminate them and still they remain. Many studies have been done to try and understand if hunting and trapping can really have a significant impact on the dynamics of their population and their impact on prey species and livestock depredation. In some studies, researchers have set up two research areas. For the purpose of the study, they over hunted and trapped coyotes from one specific test area while having another test area left alone to see the difference in both. The over hunting in one test area showed short term improvement in some small game species numbers and no change in others. Long-term coyote populations reflected little change over the course of time as soon as the hunting and trapping ended. Immigrant coyotes moving in and increased litter sizes remaining steady repopulated the area quickly.

The average litter size in Iowa for a female is 5-6 pups. They can range from 4-8 pups however. Litter sizes can vary and are closely linked to prey availability. Even yearling females can breed, but those that do are limited. Coyotes can carry many diseases but the spread of hookworm and other endoparasites are their most intense killer. They can severely debilitate juveniles. Hookworm is a parasite that lives in the small intestine of its host inducing major damage through blood loss causing anemia. In many studies, it has been estimated that 95% -99% of all pups born in the study areas are infected with hookworm, most usually through their mother’s milk. If the levels of hookworm larvae are high enough in their bodies at a young age, then the result can be death. Heartworm is a parasitic roundworm that resides in the pulmonary arterial system causing extensive damage to the host’s lung vessels and tissue. Heartworm infestations often times prove deadly to coyotes.

Vince Evelsizer, furbearer and wetland biologist for the Iowa DNR, described a few other diseases to me. “The most important viral infections are distemper and canine hepatitis. Surprisingly, rabies is not common in coyotes despite its prevalence in other coexisting furbearers such as striped skunks and red foxes. Sarcoptic mange is the main ectoparasite, but studies outside of Iowa have shown that even though they get it, coyote population dynamics and abundance are generally unaffected.”

Diet

“Here in Iowa, a coyote’s diet is actually composed mostly of cottontail rabbits, mice and voles,” Evelsizer added. Like any predator though, we all know that they will eat whatever they can get to fill an empty stomach. “So, yes they will eat game birds such as quail, pheasants, turkey, etc. Research has shown they actually tend to eat more small mammals than birds.” Evelsizer noted. In summer months, coyotes will feed upon grasses, berries seeds and fruits as well to sustain them. Their ability to ingest such a wide variety of different food groups helps them sustain themselves throughout the year. Livestock and deer make up a smaller percentage of overall diet, but during fawn and lambing seasons some coyotes may target them. A larger kill can feed them over the course of several days instead of having to hunt for each and every meal over the same time span. During the spring when there are extra mouths to feed, a fawn, lamb or calf may be too enticing for parent coyotes to resist. Coyotes can then develop a preference for this food source if it is readily available within their home range and in the case of sheep, may kill many throughout the year. The same could be said about deer and deer fawns in Iowa because they are such an abundant prey species that live so closely to the coyote.

Losses to sheep producers in Iowa from coyotes and dogs are estimated at more than $500,000 annually in recent years. More than 40% of Southern Iowa farmers responding to a survey said they had sheep killed by coyotes or dogs during a recent year. Losses from predators were nearly as high as they were from disease and other causes. Coyotes kill out of necessity and will generally feed on one kill at a time whereas wild dogs are more apt to thrill kill, often leaving several dead among the wreckage of one nights fun rampage. Determining whether a coyote or wild dog has killed can be done. Coyotes will generally attack by biting sheep in the neck and maintaining a constant grip until the victim suffocates or dies of internal bleeding. They have also been known to hamstring their victim or crush the skull of small lambs. Wild dogs often leave large wounds all over the carcass in more random fashion and leave more wounded within the flock. There are several ways of prevention. Introducing a protective dog or two into the sheep herd is a solution that works well. Keeping ewes closer to a building or confined to a building during birthing season or while lambs are little reduce predator’s opportunities. Some believe in leaving resident coyotes alone that are causing no harm. Once a local pair is eradicated, a new pair will usually move into the area the next breeding season.

Coyotes generally receive a lot of blame when livestock or other large game species are found dead even if not always deserved. They are not the homicidal killer that some give them credit for but there is no doubt that the coyote is capable of making a meal of many of the species that we hold dear. They hold an important presence in the ecosystem helping to balance things out. By all indications, coyote numbers appear to be strong in Iowa currently. We know that hunting and trapping can make a viable difference in holding their population in check but it is our sustained involvement that is necessary for the long term, which makes passing down the importance of hunting and trapping to the next generation all that more important.