Predators Are What They Eat

There's a reason it's said predators will eat anything that doesn't eat them first. They have adaptive diets, to say the least. But how adaptive are they?
Predators Are What They Eat

It’s been said a coyote will eat anything that doesn’t eat it first. That is, to some extent, true. They are one of the most adaptable creatures on the planet and will eat a wide variety of food.

What many of us believe, though, doesn’t necessarily jibe with science. Take whitetails, for instance. Many hunters are certain coyotes are killing lots of deer. A number of studies that have examined coyote scat have found that whitetails do indeed make up a large percentage of their diet. Researchers in Virginia collected 395 coyote scat over a 2-year period and examined the contents using visual matching. Seventy-four percent of all scat analyzed had evidence of deer in it.

“We were able to identify deer hair by examining it under a microscope and comparing it to samples from road-killed deer and other sources of known deer. We could also verify other species by comparing hair samples, as well,” says Dana Morin, a post-doctorate researcher at Cornell University. “We also used tooth patterns to identify small mammals, which all have distinct and identifiable patterns among the different species.”

While rodents were eaten all year, deer made up a larger portion of coyote diets during specific periods. The predators were relying heavily on deer in January, March, June, July and November.

“We know deer make up a large portion of the diet of coyotes, but we don’t know whether they are killing live deer or scavenging. Other studies have found that about 80 percent of the deer they eat are already dead,” adds Morin. “A portion of the rest could be injured from a number of things  and some may be healthy at the time of their death. We don’t know for sure.”

Morin also didn’t know if coyotes ate from a single carcass for an extended period or if they were able to find multiple deer during their normal travels. In other words, the presence of whitetail hair in coyote poop doesn’t necessarily mean they are killing and eating a high number of deer. They could instead be eating the same deer for several days or they might be scavenging road-kill whitetails or those shot and unrecovered by hunters.

What also could not be verified in her study was how many fawns they killed. However, it’s a relatively safe bet that many, if not most, of the deer they consumed in June and July were fawns. A number of studies conducted throughout the South and Southeast found that coyotes eat lots of fawns during June and July. On the contrary, the high amount of deer hair in coyote scat in November and January may be the result of gut piles and unrecovered deer during hunting season. Although it does happen, it’s rare for coyotes to kill a healthy adult deer. Of course, deep snow can make it easier for a pack of coyotes to catch and kill large mammals.

Another study conducted in northwestern Wyoming found that deer and elk made up a large percentage of coyote diets in that region, as well, with mule deer showing up in nearly 30 percent of the scat in the winter. Elk was in 14.6 percent and moose hair was found in nearly 11 percent of coyote scat. However, researchers could not determine if the predators were eating dead animals or if they were killing living ones.

“Based on my study and on others, it’s pretty obvious coyotes are opportunists that will eat just about anything. They will take the easy meal over the hard one if they have a choice,” says Morin. “In other words, they’d rather eat a dead deer than try to catch a live one.”

They also don’t eat just deer. Morin’s study found a wide variety of small mammals, including everything from squirrels and voles to rabbits and rats, in the scat she sampled. A few had evidence of raccoon, possum and even skunk and red fox. Again, though, those smaller predators could have been road-kill.

Wyoming coyotes also had a high abundance of smaller mammals. Voles, gophers and red squirrels were a common food item in the summer, but much less so in the fall and winter. Snowshoe hares were also a large part of their diet, but mostly in the fall.

Researchers speculate the lower incidence of snowshoe hare consumption may be a result of the abundance and vulnerability of ungulates (deer, elk, moose) during periods deep snow, which also accounts for winter kill of large mammals. They also wonder if deeper snow allows the hares to escape predation better. Their white coats not only blend in better, they are capable or running across the snow more efficiently than a coyote.

Summer and fall meant Virginia coyotes switched to diets heavy on fruit and other plant matter. Coyotes consume everything from wild grapes and paw paws to blueberries and even acorns. Morin also found a handful of scat with such crops as soybeans, corn and even garden vegetables in them. The Wyoming study found a high abundance of whitebark pine seeds in coyote scat one particular year.

“Snowfall was below average during that winter,” wrote Utah State University researcher Jennifer Dowd, the study’s lead author. “Being a low snow year, possibly coyotes were able to more readily access whitebark pine seed caches made by red squirrels than during the following year when deep snow might have prohibited them from excavating caches.”

Both studies examined diets of rural coyotes. As the predator expands its range, it’s becoming more frequently sighted in urban and suburban settings. Many of the same wild foods are available, but coyotes have abundant access to a more domesticated food: house pets. Various research, however, found that neither cats nor small dogs account for even a small portion of an urban coyote’s diet.

Scientists with the Urban Coyote Research Project near Chicago analyzed more than 1,400 coyote scats and found evidence of house cats in just 1.3 percent. However, they could not determine if the cat was alive or dead when the coyote found it. Other studies have shown equally low rates of house-pet predation. Just as country coyotes rely on small mammals, road-kill and various plant matter, so do urban coyotes.

Cat Food

Suburban bobcats don’t prey on pets, either, according to at least one study conducted in southern California. They and their rural counterparts are opportunistic, but unlike coyotes, their diet consists almost entirely of mammals. Morin examined 348 bobcat scat collected in western Virginia. Squirrels were the most common food, with evidence of squirrel in 199 scat. Whitetail deer was present in 126 droppings. Similar to the coyote samples she looked at, deer was most abundant in bobcat scat in June, which is when fawns are born, and in the winter when gut piles and unrecovered deer were available.

Fruit and other mast did make up a small portion of their diet, but birds and even reptiles occurred on an infrequent basis. That’s also what researchers in Georgia found. They wanted to know if bobcats were a significant predator of bobwhite quail, which are facing serious threats throughout much of their historic range. The good news is that quail remains were found in just two of 135 scats sampled. Bobcats in the study area, which is managed intensively for quail, preyed heavily on small rodents. Cotton rats were the most common food source, and rodents were found in 91 percent of all scat samples.

Surprisingly, deer remains were in just 9 percent, with the highest occurrence in the summer. The study’s authors suggest the high prevalence of rodents and birds other than quail is simply a product of the habitat. Since the land is managed for quail, it consists of dense, low cover, which is high-quality habitat for a variety of small mammals and songbirds as well as quail.

Fox Food

Red fox don’t eat quail to any significant degree, either. They aren’t much different than their larger cousins. Just as coyotes eat a wide variety of foods, fox also eat what’s available when it is available. A study conducted on Assateague Island, Maryland found a high percentage of scats contained mammals. Cottontail rabbits were the most prevalent, but mice and voles were a common food as well. So were birds, and to a lesser extent, insects and a variety of other plant matter. The fox in the study area also ate a lot of crustaceans. Assateague is a barrier island, so crabs, which were found in 65 percent of the scats sampled, are likely available on a regular basis.

There are no crabs in the Dakotas, but there are lot of ducks, particularly during the spring and summer. That’s why so many duck carcasses were found at red fox dens during one study in North Dakota. One fox den had 33 duck carcasses around it, but the average for all dens was five ducks. Red fox populations are declining throughout the Dakotas, possibly as a result of increasing coyote populations, so they are not viewed as a significant threat to waterfowl. Neither are coyotes. A number of studies in the Prairie Pothole Region, also known as the duck factory, found that ducks make up a very small portion of a coyote’s diet. They do eat a lot of deer, though.


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