Predators and Deer: Separating Fact from Fiction

One thing I’ve learned during more than two decades of working closely with hunters is that they don’t like competition from other predators, regardless of whether they walk on two legs or four!

Coyotes, foxes, bobcats, black bears and the like are often seen as direct competition for the same deer hunters pursue. But are predators really a threat to well-managed, huntable whitetail populations? In this column, we’ll take a look at what the scientific research reveals and how you can use that information to implement a sound and justified predator-management program where you hunt.

It’s Complicated

Although predators are often blamed for reducing deer numbers below the density deer hunters would prefer, the truth is that predator-prey interactions are far more complicated than they appear on the surface. For example, one unintended consequence of eradicating coyotes from the landscape can be a population explosion of “mesopredators,” or medium-sized predators, such as skunks and raccoons, that coyotes typically manage by preying on them. An unnatural explosion in mesopredators could result in a dramatic increase in turkey and quail nest predation. This factor, coupled with poor spring nesting conditions, could result in a very poor hatch year. This initial human-induced coyote control then has a ripple effect two to four years later, as turkey hunters in the area suffer from a lack of mature toms to hunt.

Most of the deer hunters I know are also turkey hunters, and when the next rut is still six or seven months away, low gobbler numbers are never a desirable result! To avoid such unintended consequences, it is critical that we not confuse predator-control efforts with a sound predator-management strategy.

If the targeted removal of a predator species can cause negative, unintended consequences, what are the alternatives? Can we use our ecological understanding to enhance conditions for prey species, other than whitetails, that predators prefer to consume? Absolutely! Understanding the biology and ecology of a predator gives us the ammunition we need to design a management program that takes the predation pressure off whitetails.

For example, we know coyotes would much rather hunt voles, mice, rats and rabbits in native grasslands or along brushy field edges. As such, many whitetail managers are catching on to the benefits of taking an off-season walk with a chainsaw to make cuts that promote early successional habitat preferred by whitetails. Ironically, these small rodents also thrive in such areas. Providing thick habitat offers a buffet of more easily hunted prey species for coyotes while providing additional safety cover and bedding for whitetails. The fact is the energy investment for a coyote to hunt and capture voles and field mice is far less than chasing down a fawn!

Ecological Value

The father of game management, Aldo Leopold, was once a proponent of aggressive predator control. However, as his career and his understanding of predator-prey relationships progressed, he famously reported, “You can’t love game and hate predators; the land is one organism.” Leopold identified that predators play important roles in ecosystem function, often reducing the spread of disease by removing primarily the sick and injured. Several well-known studies have been conducted all across the coyote’s range to prove that alteration of a predator’s density has important consequences for its prey.

A landmark study was conducted in Texas in 1972 by Frederick Knowlton. Knowlton looked at average pregnancy rates and litter sizes of female coyotes under intensive coyote control. He found that coyotes will exhibit a “density-dependent response” by increasing pregnancy rates and litter sizes when there are fewer coyotes on the landscape. In fact, Knowlton found that under intensive control efforts, the remaining coyotes produced litters averaging 7.2 pups, under moderate control, 4.5 pups, and under light control, 3.5 pups.

Research by one of my former college advisors showed that a well-nourished coyote has the potential to produce 10-12 pups to compensate for reduced density. Unfortunately, even many biologists have failed to keep these basics of predator ecology in mind as they make comments about predators acting as competition for hunters.

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When to Manage Predators

Predator management is a great tool to have in the tool box. Considering the complexity of predator-prey relationships and the potential for unintended consequences of haphazard killing of high numbers of predators, when should a deer hunter initiate a predator-management program? The answer is simple:

Predator management is warranted when the natural ecosystem has been disrupted by human action and external actions are required to restore balance. If you are unable to isolate and identify whether significant number of animal losses are occurring, contact a wildlife biologist for assistance.

I’ll never forget the look on my client’s face when I suggested they stop worrying so much about killing coyotes out of fear they were eating too many fawns. He really thought I was crazy when I implied the relatively low coyote predation on fawns was potentially improving the conditions of his deer herd. The fact is, through our trail-camera surveys, harvest data and observational data, we simply could not isolate and identify a significant reduction in his fawn recruitment rate from coyote predation. I attributed that to our sound habitat-management plan that increased the nutritional carrying capacity of the property, along with the evolved mechanisms employed by whitetails to counter small, insignificant losses to natural predation. Portraying coyotes as serious competitors for “your” deer might sound sexier, but facts don’t care about feelings.

My goal here is not to discourage you from hunting or trapping coyotes, black bears, bobcats and other predators. However, I do urge you to consider your goals and whether predators such as coyotes are truly causing major compensatory losses, and any unintended consequences prior to initiating a predator-management program. When it comes to predator-prey relationships, you should never aim to “control” predator numbers but always focus on a balanced management plan. Additionally, if you can’t identify any major predatory losses causing deer densities to remain below the carrying capacity, it’s fair to ask whether you really have a predator problem.

Finally, I would argue there is no competition between hunter and predator, merely a delicate balance. The fact is predators are a valuable component of the ecosystem, and reckless attempts to control them are neither warranted not advisable.