Researchers hoping to collar more moose in Isabella study

Field Editor

Grand Rapids, Minn. Wildlife biologists will be capturing and
radio-collaring up to 40 northeastern Minnesota moose this winter,
hiring a professional helicopter crew to catch the animals. DNR
Wildlife Biologist Mark Lenarz says the heli-capture will further a
moose research project that is entering its second year.

Last February, 24 moose were captured and outfitted with radio
collars in a study area that includes the vast boreal forest near
the community of Isabella.

Biologists hope to learn more about the movements and mortality
rates of the northeastern moose herd, which has a relatively stable
population. The radio-collared animals are monitored by federal
biologist Mike Nelson, who makes regular flights in the vicinity as
part of a long-term wolf and deer study.

So far, six of the radio-collared moose have died. One cow was
killed by wolves, a bull was killed by hunters, and four cows died
from an unknown cause.

“We’ve got something mysterious going on,” Lenarz says.

The four cows died between the end of May and the middle of
December, a time of year when moose mortality is typically low. All
of the cows were emaciated and had low fat reserves. Even bone
marrow fat, usually the last reserve to be used up, was low.

Blood samples from the animals were collected and tested. All
tests came back negative, including a test for the common brainworm
disease that moose can contract from deer. A literature review
revealed few clues to the cause of mortality. Lenarz hopes to
involve the DNR’s new veterinarian, Dr. Gary Hart, in further
disease sleuthing.

Is Lenarz concerned about what the mysterious moose deaths may
portend for the northeastern herd?

“Yes,” he says. “I am concerned in the context if this is a
major source of mortality and there is nothing we can do about
it.”

Last weekend, Lenarz and two tribal biologists followed up on a
report that loggers had discovered a sick moose unable to get up
near Two Island Lake in Cook County. They found the animal, which
was not part of the radio collar study, and it was unable to
stand.

They euthanized the moose and necropsied it to collect tissue
and blood samples. They are now awaiting test results.

Annually, non-hunting mortality rates for moose are usually 8 to
12 percent, but among the study animals the rate already tops 30
percent. Surprisingly, state and tribal hunting accounted for only
one moose death. Lenarz says that three radio-collared bulls in the
study were living in areas easily accessible to hunters, but only
one of the three was killed.

The study is beginning to shed light on moose movements.

Previously, biologists were only certain about the places where
moose were found during winter, when the annual aerial population
survey is conducted. They did not know if moose, like northwoods
deer, made semi-annual treks between summer and winter ranges.

So far, it appears moose are mostly homebodies that stay within
a home range of about two square miles. One bull has been an
exception. In spring, the animal travelled from the vicinity of the
Four Mile Grade across the Boundary Waters Canoe Area Wilderness to
Gabamichigami Lake, traversing some of the worst blowdown areas in
just a week. In early winter, the bull returned to the area where
it was captured.

Lenarz also hopes the radio-collared moose will help biologists
determine the effectiveness of the aerial population survey,

Despite poor snow conditions, which make it difficult to see
moose from the air, the annual count is occurring. Determining the
number of radio-collared animals within the survey plots and how
many were actually seen by observers will help researchers
determine how many of the moose in a given area are visible from
the air.

If research money is available, the radio collar study will
continue for several seasons, giving biologists valuable insight
into the life and death of northeastern Minnesota moose.

“We should learn an awful lot about the moose population,”
Lenarz says.

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