Coyotes lead way in deer deaths

[Lee Borgersen]

Coyotes lead way in deer deaths
 
Results from a study in the U.P. show coyotes kill more deer than other predators.

Wolf, bear, coyote or bobcat.

If you had to name the carnivore that kills the most white-tailed deer in the Upper Midwest, which would you pick?

If you are thinking smaller rather than larger, you're on the right track.

The answer is coyote, at least according to preliminary data from a study in the Upper Peninsula of Michigan.

Work published recently by Mississippi State University researchers shows coyotes as the leading predator of deer, including fawns and adult females.

Second? That would be the bobcat.

The study, which started in 2009, is being conducted in 350 square miles of Menominee County in the eastern U.P.

The area includes a mix of forested and agricultural lands. It is home to deer, wolf, bear, coyote, bobcat, red fox, gray fox, fisher and badger.

In other words, for all practical and ecological purposes, it's northern Wisconsin (and would be if someone hadn't drawn a boundary line years ago).

To obtain the data, researchers have trapped deer and predators and fitted the animals with various tracking devices.

Female deer also have been implanted with transmitters that allow researchers to find the animals when they give birth. The fawns are then fitted with expandable radio collars.

In all, 57 adult deer and 44 fawns have been captured and fitted with tracking devices.

The data are from Jan. 1, 2009 through Aug. 31, 2010. Though preliminary, they are showing some very interesting results.

Coyotes in the study area were responsible for 13 fawn mortalities, followed by bobcat (9), unknown predator (5), abandonment (4), unknown agent (3), black bear (2), vehicle collision (2), wolf (2) and bald eagle (1).

Among adult and yearling female deer, coyote killed 6, followed by wolf (3), black bear (2), drowning (2), birthing complications (1), vehicle collision (1) and unknown predator (1).

Annual survival of adult and yearling female deer was 73%. Survival of fawns was 37%.

Utilizing two techniques for comparison, the researchers estimated deer density in the study area at 16.1 and 14.8 deer per square mile.

Could the results be linked to an unusually high number of coyotes and bobcats in the study area?

The researchers have placed tracking devices on at least three individuals of each major carnivore species in the area.

But they are still working on getting estimates of carnivore abundance in the study area, said Jerry Belant, assistant professor of wildlife ecology and management at MSU and faculty adviser for the project.

Belant said last winter there were at least 11 wolves in two packs in the study area. But the researchers have not yet quantified the abundance of bears, coyotes and bobcats in the area.

The project is supported by the Michigan Department of Natural Resources, Safari Club International, Safari Club International-Michigan Involvement Committee and Safari Club International-Northwoods Chapter.

It lists its leading objectives as: Estimate survival and cause-specific mortality of white-tailed deer fawns and does; estimate proportion of fawn mortality attributable to black bear, coyote, bobcat and wolf; estimate number and age of fawns killed by a bear, coyote, bobcat or wolf during summer; provide updated information on white-tailed deer pregnancy and fecundity rates.

The study is planned to continue for a couple more years. A similar Wisconsin study is beginning this year.

Research being conducted on the Savannah River Site in South Carolina also is shedding light on the role coyotes play in deer predation. In that work, though not complete, coyotes may be responsible for lowering the deer population.

Coyotes have long been known to be efficient predators and to play an important role in the North American ecosystem. Of course, the same can be said of wolves, bears and bobcats.

But it takes solid research, like the studies in progress in the U.P. and South Carolina and yet to come in Wisconsin, to advance the discussion of predators and deer beyond emotion and individual experience.


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