By: Richard P. Smith.
Do you want to see more bucks or bears in Michigan during the future?
Before you answer that question, some background information about both species
of big game is important. Due to the use of a method in 2012 to estimate the UP bear
population that is prone to errors, the DNR thought bear numbers were declining
and reduced bear hunting licenses by 32% from 2012 through 2014 to allow the
bear population to increase. The number of bear licenses issued to hunters in the
Lower Peninsula (LP) were cut back at the same time. By 2014, a new method of
estimating bear numbers showed that the population was not declining in 2012
after all and that there was no need to reduce the number of bear licenses.
In spite of the new information that showed it wasn’t necessary to reduce bear
licenses between 2012 and 2014, bear license quotas were reduced even further
during 2015 at the request of bear hunters who wanted to see more bears. Only
6,951 bear licenses were issued by the DNR during 2015, 880 fewer than the 7,831
available during 2014. Bear license totals for 2013 were 7,906 and 7,991 for 2012, a
reduction of 3,751 from the 11,742 bear tags available for sale to hunters in 2011.
While bear numbers were increasing between 2012 and 2015 due to fewer hunting
licenses, three severe winters in a row had the opposite effect on UP deer and some
of those winters negatively impacted whitetails in the northern Lower Peninsula,
too. Many deer died during the winters of 2012-2013 and 2013-2014 due to deep
snows and cold temperatures followed by late spring breakups. The same factors
affected deer in parts of the UP again during the winter of 2014-2015. As high as
75% of the deer population was lost in portions of the UP due to those winters.
The bottom line is reduced hunting pressure on black bears have allowed them to
increase to the highest levels they have been in years and severe winters combined
with predation from thriving predator populations have reduced deer numbers to
the lowest levels they’ve been at in years, especially in the UP. The UP is home to
most of the state’s bears and almost all of the state’s wolves and there’s no shortage
of coyotes either. Bears are increasing and expanding their range in the LP, where
coyotes are abundant and there are a few wolves.
What does the presence of more bears have to do with deer numbers?
Black bears are one of the most important predators on whitetail fawns and they
also prey on adult whitetails, when they get the chance. The more bears there are,
the more whitetails they eat, which results in fewer deer. It’s simple math.
One of the reasons that black bears take such a high toll on whitetail fawns is the
peak of the bear breeding season overlaps the time frame when most fawns are
born, which is the month of June. The fact that fawns instinctively try to hide from
predators their first weeks of life by lying motionless on the forest floor increases
their vulnerability to bears as well as other predators. Adult male bears are almost
constantly on the move in search of receptive females during June and July,
increasing their opportunity to stumble upon fawns. Although female black bears
don’t cover as much territory as males during fawning season, they travel enough
during their normal daily activities to claim their share of fawns.
When deer numbers are healthy and bears are properly managed through hunting,
bears have little obvious impact on whitetail populations, but when there are more
bear than deer like there are now in parts of the UP and whitetail numbers are
already depressed through severe winters, predation from bears, when combined
with other predators, can further reduce the deer population. At the very least, they
can slow recovery of the herd. Recent research being conducted in the UP by
students from Mississippi State University in cooperation with the DNR is providing
new insights about bear predation on whitetails, but earlier studies also provided
valuable information on the topic.
The current predator/prey study has been underway in the UP for about seven
years. The first three years were spent on a study area in the low snowfall zone of
Menominee County. Starting in 2012, the project shifted to a study area in the mid
snowfall zone of Iron County. On June 21, 2013, graduate research assistant Tyler
Petroelje and a technician were working on the project in Iron County when they
documented the predation of a fawn by a bear.
Coyotes, wolves, bobcats and bears are all fitted with global positioning system
(GPS) radio collars as part of the study that pinpoints a predator’s location every 15
minutes. Clusters of points in a small area sometimes mark the location of a kill.
Petroelje and the technician were investigating a cluster of locations recorded by a
wolf’s collar when they heard a fawn bleat nearby.
When they heard the fawn bleat a second time Tyler said, “Grab the fawn kit,” and
they started running toward the sound. Soon after the second fawn bleat, Tyler
heard a doe snort. “I saw the doe and followed her to a gravel pit where she was looking
off to one side,” Petroelje commented. “When the doe saw me, she took off, but I knew something
had to be on the fawn. After reaching the spot where the doe had been, I clapped my
hands. When I clapped them a second time a bear’s head popped up from behind a
berm.” The bear ran off upon seeing Tyler. “The fawn we heard was where the bear had been,”
the researcher continued. “The fawn was dead and the bear had already eaten its heart,
lungs and liver. It only took us two or three minutes to get there.”
That was the first and only time anyone from the team had been present when a
fawn had been killed by a predator. Most often they have to try to determine what
happened by investigating location clusters from collared bears or homing in on the
mortality signal from a radio collar worn by an adult doe or fawn. Each year of the
study they fit as many adult does and newborn fawns as possible with radio collars.
When a doe or fawn is killed, the collar goes into a mortality mode and then students
try to determine what killed the deer.
According to preliminary results from the Iron County study area, black bears were
responsible for 19% of fawn mortality, ranking them right behind coyotes at 21%.
It’s interesting to note, however, that it was impossible to determine which predator
killed 21% of the fawns that were examined. Bears were most likely responsible for
some of those fawn’s deaths, too.
During 2014, black bears killed 57% of the fawns radio collared for the study that
are known to have been taken by predators. Predators killed a total of seven fawns.
Bears ate four of those and one each was preyed upon by a coyote and bobcat. The
identity of the predator that killed the seventh fawn is unknown.
Black bears accounted for a similar mortality rate of collared fawns during a study
conducted in Wisconsin’s Chequamegon National Forest. During that study, 45 fawns
were fitted with transmitters in the same area where 52 bears were wearing radio
collars. Bears were responsible for seven out of 12 fawn deaths (58%). Coyotes only
accounted for the loss of three fawns.
The loss of four or seven fawns to bears during the course of a year may not seem
significant, and it wouldn’t be if that were all it was, but the results of those studies
are simply a small part of the picture. Those studies only document a fraction of the
number of fawns being killed by bears as well as other predators, on the study areas.
It would be easy to conclude that not all black bears kill fawns based on these
studies, for instance, since the number of fawns that were killed is so low compared
to the number of bears present.
Results of other studies do indicate, however, that most black bears do prey on
fawns on an annual basis. Dr. Lynn Rogers from Ely, Minnesota pioneered a unique
approach to studying bears that involves habituating study animals to the presence
of people, so people can walk with the bruins to observe their behavior. One adult
female black bear that was part of that study was observed killing seven fawns in
northern Minnesota where deer numbers are low during the course of one fawning
Terry DeBruyn, who is now the forest ecologist with the Hiawatha National Forest,
also walked with some of his study bears in the UP’s Alger County and he observed
those bears taking multiple fawns each year, too. The most fawns a single bear was
seen killing during one year was six. All of the bears that were observed during
those studies were females, however, and males probably kill more fawns than
females since they cover more ground.
Walking with individual bears is obviously the most accurate means of documenting
fawn predation, but not even that provides the full extent of the problem because
study bears were not being watched all of the time. There were days at a time when
fawns were being born that no one was with the bears. So fawn predation was
probably even higher than what was observed.
It’s clear that adult bears play an important role as predators of whitetail fawns, but
what about yearlings that are 1 ½ years old and on their own for the first time?
Retired DNR deer researcher John Ozoga found out what impact single yearling
black bears can have on fawn survival on two separate occasions. For many years,
Ozoga studied whitetails in a one square mile enclosure at the Cusino Wildlife
Research Center in Shingleton. Yearling black bears got in that enclosure twice while
fawns were being born.
One of the yearlings weighed 100 pounds and the other tipped the scales at 66
pounds. Both times yearling black bears got in the enclosure, they increased fawn
mortality on that square mile by 22%. It’s impressive that single black bears of that
size can have so much impact on fawn survival. Imagine what thousands of them can
do across the state.
The DNR’s most recent estimate of the number of black bears that are a year or more
in age as of September 1, 2014 is 11,000. Since that time, the number of black bears
in the state has increased due to reduced hunter harvest the last two years and the
adding of two more year classes of yearlings.
By this year, there could be in excess of 13,000 bears that are at least a year old in
Michigan. If each of those bears only killed one fawn, there would be 13,000 fewer
deer this fall. Two fawns apiece would put the loss to bears at 24,000. Since some
bears are known to prey on more than two fawns each, fawn predation from bears
could easily be between 30,000 and 50,000 this year.
UP deer hunters only harvested an estimated 25,882 deer during 2014 deer seasons,
according to the DNR Harvest Report for that year. UP bears will certainly kill more
deer than that this year. Hunters who think increasing bear numbers won’t have an
impact on the number of deer they see in the future should reconsider.
Black Bear Predation on Adult Deer
On November 4, 2009, Mississippi State University researchers working on the
predator/prey study in Menominee County confirmed a healthy 7 ½-year-old doe
radio collared for the study was killed by a black bear. On October 1, 2007, Iron River
attorney Steve Polich saw about a 300-pound male black bear kill an injured doe in a
matter of seconds while he was bowhunting for deer. Researchers in Canada on a
number of occasions have documented the predation of adult moose and caribou by
adult male black bears. An adult deer is going to be easy pickings for predators
capable of killing adult moose.
Seven Michigan black bears from the northern LP have been diagnosed with bovine
TB, presumably from eating deer or cattle infected with the disease. Bruins are
excellent scavengers, so they most likely got the disease from eating hunter-killed or
road killed deer or the gut piles from those animals. Bears could have also
contracted TB from eating diseased cattle that were discarded.