Deer Management/Status Overview
341
Sparta Deer Management Unit
Area Description:
The Sparta Deer Management Unit (DMU) lies
in the Southern Lower Peninsula (SLP) region and
covers Kent, Ottawa, and south Muskegon
counties. The majority of public hunting
opportunities in this DMU are available on
Muskegon (10,065 acres), Rogue River (6,135
acres), Cannonsburg (1,347 acres) State Game
Areas and Bass River State Recreation Area (1,665
acres). Topography varies from river floodplains
and bluffs, to outwash plains and gently rolling
hills. Soils are generally well-suited to row crop
agriculture and orchards. The landscape is highly
fragmented due to the predominance of
agriculture on privately-owned lands, mixed with
urban, rural residential and commercial areas.
Private lands constitute 96% of the DMU. Aside
from public lands which are predominantly
forested, habitat providing cover for deer (e.g.,
woodlots, shrub/brush, and wetland) is
interspersed across the landscape (Table 1, Figure
1).
Table 1. Habitat composition of DMU 341 as compared to only the
public hunting lands in DMU 341.
Habitat
Forest (%)
Agriculture (%)
Grass/Shrubland (%)
Wetland (%)
Developed (%)
Water (%)
Bare/Rocky (%)
341
25.4
39.6
9.7
6.4
16.0
2.2
0.7
341 Public Lands
53.8
3.5
8.9
27.8
1.9
2.9
1.1
Two main goals guide the deer management
in this DMU: 1) impact management; and 2)
hunting opportunities. Impact management refers
to reduction of undesirable effects associated with
deer over-abundance. Crop damage, deer-vehicle
collisions, poor forest regeneration due to overbrowsing, and urban deer issues are examples. In
an effort to find a middle-ground in which deer
numbers provide ample hunting and wildlife
viewing opportunities and mitigate unwanted
impacts, we review data
from several sources to adjust the harvest strategy
as needed. These data include deer harvest data
from check stations and an annual mail survey,
deer-vehicle collision data from the Michigan
State Police, and deer-related information
collected by regional wildlife biologists (e.g.,
number of Crop Damage Permits, municipal
complaints, habitat assessments, etc.).
Deer Harvest Analysis:
The decline of both antlerless and buck
harvest between 2008 and 2013 is statistically
significant (Figure 2). This is due to a reduction in
deer population, although hunter behaviors can
also influence these trends. The liberalization of
antlerless permits in the southern Michigan DMU
486 was intended to limit the productivity of the
deer herd and respond to the finding of CWD
(Chronic Wasting Disease) in a captive deer facility
in Kent County, and contributed to a population
decline in this DMU. Other environmental factors,
such as poor weather immediately preceding
fawning, increased predation, and changing
agricultural practices, can also impact deer
numbers. Ultimately, determining a cause of any
population adjustment is difficult when assessing
a large geographic region.
Human decision making can also impact
harvest numbers. Hunters’ decisions to target
older deer and pass on younger bucks may result
in reduced harvest numbers and increased hunter
effort, as there are fewer deer in older age classes.
Similarly, hunters may self-regulate harvest of
antlerless deer for a variety of factors, such as a
perception of too few deer.
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Deer Management/Status Overview
Figure 1. Habitat and land use distribution in Deer Management Unit 341.
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Deer Management/Status Overview
Figure 2. Annual harvest estimates for antlered and antlerless
deer DMU 341 2003-2012.
The concurrent statistically significant drop in
harvest (Figure 2) and increase in number of days
afield per hunter in DMU 341 suggests a
population decline in deer. Social factors (i.e.
hunter perceptions and goals) may have some
influence over both harvest and effort, but it is
unlikely that hunter attitudes would have shifted
enough in this time span to impact harvest and
effort to this degree. More likely, it is a reduction
in deer population leading to fewer deer being
harvested and more effort being expended by
hunters to harvest deer.
Table 2. Age structure of antlered deer harvest in DMU 341 20042013.
Figure 3. Average number of hunters in DMU 341 2003-2012.
Additional Population Assessment Factors:
Deer-Vehicle Collisions
Deer-vehicle collisions (DVC) are commonly
used as an index to the deer population trend, the
idea being that high rates of DVCs are correlated
with high deer populations, and vice versa.
Research has shown that there are other factors
that influence the rate of DVCs. Habitat proximate
to the roadway and highway characteristics can
blur the relationship between deer population and
DVCs. However, DVC data can provide useful
information if contextualized as one part of a deer
population assessment.
Age Category
Year
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
Total
1.5
73.4%
73.4%
75.7%
69.8%
82.4%
69.7%
74.8%
74.5%
68.6%
71.7%
74.6%
2.5
14.6%
14.4%
14.5%
18.0%
11.2%
14.6%
12.1%
12.5%
18.8%
14.1%
13.8%
3.5
10.0%
10.2%
8.1%
9.6%
5.4%
13.1%
11.4%
9.8%
10.1%
12.1%
9.6%
4.5
2.0%
1.8%
0.7%
1.9%
0.8%
2.2%
1.1%
1.9%
1.9%
2.0%
1.5%
5.5+
0.3%
1.0%
0.6%
0.1%
0.3%
0.7%
1.4%
0.5%
DVCs indexed by vehicle miles travelled have
declined significantly from 2001-2010 in the
Sparta DMU. These data are provided by the
Michigan State Police. Although changes may have
occurred in law enforcement response and
recording of DVCs over time, we assume they have
remained consistent enough to provide an
accurate estimate of DVC rates relative to vehicle
miles driven. The displayed decline in DVCs is an
additional indicator that the Sparta DMU deer
density has dropped over the past decade.
0.4%
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Deer Management/Status Overview
Figure 4. Deer-vehicle collisions in DMU 341 2001-2010.
Deer Management Assistance and Crop Damage
Permits
Deer Management Assistance Permits
(DMAPs) or “Block permits” allow for the harvest
of antlerless deer by private landowners or their
designees during legal deer hunting seasons.
DMAP requests are tracked by MDNR and may
trend with deer populations (i.e., an increase in
deer density may result in additional DMAP
requests). In the Sparta DMU, the number of
DMAP requests has historically been low.
However, since 2009, the number of DMAPs
issued and antlerless deer harvested by these
permits has declined by over 85%.
Crop Damage Permits are also requested by
landowners, but allow for the harvest of antlerless
deer outside of legal hunting seasons to address
agricultural damage. Requests for Crop Damage
Permits sometimes do not reflect population shifts
as quickly as hunting harvest data. Since 2009,
both the total of Crop Damage Permits and deer
harvested by these permits has declined by
approximately 50%.
Deer Condition Data
Yearling main antler beam diameter,
measured just above the burr, and number of
points are useful for determining deer body
condition. These measurements are recorded by
MDNR as hunters voluntarily present harvested
deer at check stations throughout the state. When
aggregated by DMU, the average antler beam
diameter and number of points for yearling bucks
over multiple years is calculated. An upward trend
indicates improving herd condition, whereas a
downward trend points to declining herd
condition. Generally, herd condition is a function
of habitat factors. An abundance of highly
nutritional food resources and good cover is
beneficial for herd condition. Depletion of these
resources through overpopulation or other types
of physical stress leads to a decline in herd
condition, observed as lower yearling main beam
diameters and antler points. In southern Michigan,
normal winter severity is not likely to impact deer
condition on a population level. Environmental
factors may impact deer condition indirectly,
though. A late frost or an especially rainy spring
can negatively influence crop production which is
a major source of nutrition in this DMU, or impact
fawn survival. Likewise, changes in land use
practices can affect cover and food resources.
In the Sparta DMU, the decline in average
antler beam diameter has been somewhat
variable year-to-year. Comparing the 2003 and
2012 seasons, antler beam diameters declined
from approximately 22.5 mm to 21.2 mm in the
Sparta DMU, an average annual decrease in this
DMU of 01.33 mm (Figure 5). The 1.30 mm
decline from 2003-12 in this DMU is slightly
greater than the estimated reduction in average
yearling antler beam diameter in the entire SLP of
1.02 mm for the same period. However, average
yearling antler points did not change significantly
in either the Sparta DMU or SLP.
It does appear that deer herd condition
declined slightly in the Sparta DMU from 2003-12.
Increased deer density resulting in heightened
intra-species competition and resource depletion
can cause this phenomenon. However, as most of
our deer population indices point to a decline in
deer numbers, this seems unlikely to be the cause.
Also, environmental influences (e.g., extreme
weather events like the 2013-14 winter season)
tend to be short in duration and impacts are
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Deer Management/Status Overview
limited to short time frames (1-2 years). We would
not expect to see environmental effects drive
down deer condition for this entire time span,
although climate change may be shifting this
perspective. Most likely, the reduction in deer
condition is attributable to several factors. High
commodity prices have led to less acreage
enrolled in national farm bill conservation
programs, expansion of row crop agriculture, and
decline in deer cover. Although agriculture can
provide highly nutritional food resources to deer,
it is seasonally available and comes at a cost of
naturally occurring food sources and cover. The
conversion of acreage from acceptable deer cover
to agriculture and removal of brushy field rows
further fragments habitat, homogenizing the
landscape and reducing the richness of a
“patchwork” of habitat types in which deer thrive.
At the same time, the human population in West
Michigan continues to grow, and landscape
development continues to convert wildlife habitat
areas to meet commercial and residential needs.
In Ottawa County alone, planners estimate that
approximately 20 square miles of county open
space will be developed in the first 20 years of the
century. Since deer populations are never evenly
distributed across the landscape, high deer
numbers in parts of the Sparta DMU may have
also reduced habitat quality.
Deer Management Recommendations:
The deer population has likely declined in this
DMU in the last decade. Deer density remains high
in parts of the Sparta DMU, however, especially
relative to other regions of the state. Density is
likely high enough to continually require the
issuance of DMAPs and Deer Damage Permits
throughout much of the unit, as harvest through
the general hunting seasons is inadequate to
relieve damage complaints.
Hunting opportunities remain good due to
continued high deer densities in parts of the
Sparta DMU, such as Kent County. However,
aggressive antlerless deer harvest in regional DMU
486 during the 2009 – 2012 time period, and the
effects of Epizootic Hemorrhagic Disease have
taken their toll and reduced overall deer numbers
in this DMU. As this unit was formerly part of
DMU 486, it is not possible to know the rate at
which antlerless tags were filled. Going back to
2008, the last year in which the three counties in
Sparta DMU were individual units, approximately
31,880 antlerless deer licenses were available in
the area now known as the Sparta DMU. The
number of 2008 licenses also reflects the fact that
the Sparta DMU does not include the entire area
of Muskegon County, only the lands in Zone 3. A
reduction in deer numbers appears to have been
occurring since 2008 and our goal is to stabilize
deer numbers in Kent County while increasing
deer numbers in Muskegon and Ottawa Counties.
The antlerless deer permit quota for 2014
represents a 22% reduction from 2013 levels
(22,500). We recommend a reduction in antlerless
permits in the Sparta DMU to 17,500 private land
antlerless permits. In the 2013 season, 1,350
public land antlerless were also available for this
area. We recommend a reduction in the public
land antlerless quota to 1,000 permits.
In addition, it is recommended that the early
antlerless season be discontinued in the Sparta
DMU in 2014.
Figure 5. Yearling Antler Beam Diameter Measurements in DMU 341
2003-2012
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