DNR defends deer count at workshop

Editor’s note: This is the first of a two-part series on how
the DNR determines harvest estimates and deer population
trends.

By Marty Kovarik Correspondent

Marquette, Mich. — The DNR and the Natural Resources Commission
held a joint deer workshop and listening session recently to
address concerns that Upper Peninsula deer hunters have about the
status of the white-tailed deer population.

During the workshop, presentations were given in an effort to
better explain the way the department arrives at deer population
trends and harvest estimates. Subjects included hunter harvest
surveys, mandatory deer checks, western U.P. deer herd indicators,
and the sex, age, kill estimator. Following the workshop, hunters
voiced their concerns to three members of the NRC.

According to Bill Moritz, DNR Wildlife Division chief, the
workshop was being conducted to improve communication between the
department and hunters in both directions and to explain the
monitoring methods and how the DNR arrives at population
estimates.

The workshop was conducted due to a recent deer management
meeting in Marquette where hunters picketed and were particularly
vocal while voicing concerns about the condition of the western
U.P. deer herd.

“After the last meeting in Marquette, the predominant issue was
to improve relations between hunters and the department,” said NRC
commissioner John Madigan, of Munising. “It’s important that people
understand how we are deriving these numbers and that they are not
just picked out of the air.”

Brent Rudolph, DNR research specialist in Lansing, began by
pointing out the long history of mail surveys used to determine
harvest and hunter effort in Michigan since 1952. These surveys
have undergone several different formal and independent evaluations
to determine their accuracy and to compare them with other various
check systems, according to Rudolph.

A harvest survey is done annually for each species, and opinion
surveys are conducted randomly to evaluate public views. For the
deer harvest survey, people are selected from the list of hunters
who purchased an archery, firearms, or combo deer license. In 2004,
52,357 surveys were mailed out to poll approximately 7 percent of
the state’s 755,930 deer hunters that year. Although only about
half the hunters respond typically to the first mailing, after
additional mailings between 70 and 85 percent eventually
respond.

In addition, to reduce the bias created by the fact that
successful hunters respond more frequently than non-successful
hunters, incentives are used. Respondents are entered in a prize
drawing that has increased the non-successful hunter response.

Rudolph uses as an example the ability to determine elections
through a small sampling of voters. To poll every voter or every
hunter would not result in additional information, but would cost
substantially more, he said.

As evidence that hunter surveys and mandatory registration
provide similar data, Rudolph cites methods for tracking bear
harvest. Since 1995 the DNR has conducted both mandatory
registration and a harvest survey to evaluate bear hunter success.
From 1995 through 2005, the results from these two methods of
tracking bear harvest virtually mirror each other.

“These two surveys track each other very closely,” Rudolph said.
“We are very pleased with the reliability of our harvest
information.”

Rudolph adds that with these surveys the DNR not only gets
information on harvest but hunter effort from both successful and
non-successful hunters, something mandatory registration would not
provide.

Rod Clute, the DNR’s big game specialist, followed Rudolph with
a presentation comparing the methods used for determining
Michigan’s harvest estimates with several other Great Lakes
states.

Currently, Pennsylvania has a mandatory postcard registration;
however, supplemental checks of approximately 28,000 deer at meat
processors showed that less than 40 percent of those deer were
registered by hunters. This means that Pennsylvania has an
estimated 60 percent non-compliance rate of its mandatory
registration system.

In contrast, Missouri had an estimated 65 percent compliance
rate after it replaced its old mandatory check system with a
telephone registration. When switched to a tel-a-check system,
hunters began reporting 20 percent more deer.

“Even with mandatory registration, these states’ harvest figures
are based on a bias because they know they are not getting
100-percent compliance,” Clute said. “So just as with Michigan,
their harvest figures are truly estimated.”

Wisconsin and Ohio both have a form of mandatory registration
and they report only the numbers that are registered. Although it
varies from area to area across the state, Ohio estimates a 70 to
90 percent compliance rate.

“In these states it is still an estimate because they don’t know
exactly how many more deer were harvested than they are reporting,”
said Clute.

According to Clute, of eight Great Lakes states, not one uses
the exact same method for determining deer harvest figures, and
each method – even though some may require mandatory registration –
is only an estimate. However, there is one common link to each
state’s harvest estimates: Just like in Michigan, these harvest
figures are used to determine population estimates and management
goals.

Michigan’s system has proved to have a small margin of error of
2 percent.

The DNR is holding a similar deer workshop beginning at 9:30
a.m., Saturday, May 13, in University Ballroom D at the Holiday Inn
in Big Rapids, located at 1005 Perry Street. This will only be a
deer workshop and will not include and NRC listening session.

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