Does Coyote Predation Truly Decrease Whitetail Deer Populations?
It seems that whenever whitetail deer populations decline in the presence of coyotes, deer hunters automatically assume that coyote predation is the cause and thus, they call for a bounty to be placed on the predators. However, the fact is that predation is Nature’s way of controlling animal populations and often, removing apex predators from a region can lead to overpopulation of game species and a decimation of the landscape as evidenced by the removal of wolves from Yellowstone National Park. However, although coyotes have long been a natural part of the food chain in many Western states, the elimination of wolves and coyotes in the Northeastern and Southeastern regions of the U.S. have enabled western coyotes to move east and repopulate regions where they were previously extinct. Plus, in the case of the Eastern verity, DNA evidence has shown that in many cases, coyotes have mated with wolves to produce a larger, more aggressive, hybrid “Coywolf” species that sometimes hunt in packs. But, is coyote and coywolf predation on deer really responsible for the decline in deer populations that some U.S. regions are presently experiencing?
Well, the answer to that question seems to be both yes and no. But how can coyote predation of whitetail deer be both responsible and not responsible for declining deer populations? There again, the answer seems to be twofold. For instance, studies have shown that coyotes in Northern and Western regions where snowfall accumulates and remains for extended periods during the winter months do manage to successfully predate upon adult whitetail deer with as many as five out of eight hunts proving successful. But, during warmer months of the year, they commonly only predate on fawns and mostly concentrate on other game species.
A 9 year study conducted in Idaho which removed both mountain lions and coyotes from a large area as well as several studies conducted in Wyoming, Utah, and Colorado which removed coyotes from areas ranging from 40 to 300 square miles, found absolutely no evidence that their removal caused an increase in deer populations. In addition, another study conducted in southeast Texas determined that while the removal of coyotes did increase the survival rate of fawns, it did not increase the overall deer population. Consequently, this evidence combined with that generated by other studies has lead researchers to conclude that coyote predation does not decrease deer populations in Western regions but, instead, it actually has a stabilizing effect.
However, at the same time, others studies have shown that this is not the case in the East where coyotes have been absent from the ecosystem for many years and thus, wildlife management agencies have commonly used doe harvest quotas to control whitetail deer populations. But, the recent migration of coyotes into the Northeast and the Southeast does indeed seem to be responsible for a significant increase in fawn mortality and thus, a significant decrease in adult deer populations. While this problem is prevalent in both regions, it seems to be especially problematic in the Southeast where studies have shown that both coyotes and coywolves, as well as other predators such as black bears and bobcats, are responsible for fawn mortality rates as high as seventy-five percent during the first three months of life. A study conducted in South Carolina in which both coyotes and coywolves were removed from three different 8,000 acre tracts for a period of three years, the survival rate of fawns did significantly increase the first year but, by the third year, deer populations seemed to stabilize at their former size.
So, why doesn’t predator control seem to work? Well, as it turns out, another study conducted in North Carolina determined that approximately one-third of all coyotes there are transients and thus, these predators often move from one area to the next and sometimes cover as much as a 100-mile circle over several months. Therefore, if the resident coyote population is eliminated, then the transients simply move in and occupy the vacated territory. In order to control coyote populations in the East, it appears that they will have to be hunted and trapped continuously and relentlessly. Consequently, there are presently some biologists in the Southeast who believe that the only way to maintain deer populations in the Southeast is to drastically restrict, or, even eliminate deer hunting altogether!
All of the information garnered from the many different studies done around the country has determined that coyote predation on fawns can indeed significantly decrease adult deer populations in some regions. But, at the same time, coyote predation on fawns is high in some areas and low to non-existent in others even across small geographic areas. In addition, even in areas where fawn predation rates are very high, hunters can usually compensate for fawn losses by reducing or eliminating doe harvests. Even if a coyote elimination program is instituted in a given area, transient coyotes will quickly repopulate vacated areas. Thus, continuous hunting of coyotes is required to maintain high fawn recruitment rates on an annual basis in specific regions.
So, it seems that although hunters commonly blame coyotes and coywolves for the reduction of deer populations in their regions or areas, studies have determined that neither coyotes nor coywolves are truly responsible for the long-term degradation of local deer populations with the exception of the Southeastern region where they do indeed seem to be at least partly responsible for an unusually high degree of fawn predation.
The real reason for decreasing deer populations in most regions is more likely to be poor nutrition due to habitat degradation caused by overpopulation and/or disease caused by the same factor as well as the elimination of much of their previous habitat due to increasing human populations.
It may very well be that deer populations in the East have been unusually high for so long due to the lack of apex predators such as coyotes and wolves that hunters in the Northeast and the Southeast perceive their abnormally high deer populations be normal for those regions when, in fact, they are actually artificially inflated due to the lack of apex predators to control the population naturally. Although coyote predation of both fawns and adult deer is a documented fact, it seems not to be the real determining factor in declining deer populations except for perhaps in the Southeast.
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