William Berg and Todd Fuller
Minnesota Department of Natural Resources
Populations and federal status updated by IWC December
, when they were worth $3, through
1965 (when all bounties ended in Minnesota), when a bountied wolf
pelt brought $35. Although bounties generally did not control
populations of other predators, they had an impact on wolves.
By the early 1900s, wolves were rare in southern and western Minnesota.
By the 1950s, wolves were gone from these areas of the state.
A wolf study conducted by Milt Stenlund in the early
1950s centered on a portion of the Superior National Forest in
northeastern Minnesota. After extrapolation to the rest of northern
Minnesota, Stenlund's data indicated a population of 450-700 wolves,
most of which resided in 12,000 square miles of main wolf range.
Through the early 1960s, wolf numbers were likely
stable (see Minnesota Wolf Population Trend graph below). From
1953 to 1965, about 190 wolves were bountied annually, and bounty
claims gradually decreased outside the main range -- suggesting
that fewer wolves existed. One estimate in 1963 put Minnesota's
wolf population at 350-700. After the bounty ended in 1965, wolves
could still be legally trapped and hunted year-round in Minnesota.
Minnesota Department of Natural Resources (MN DNR) records indicate
that about 250 wolves were killed annually until 1974, when wolves
became completely protected under the federal Endangered Species
Act of 1973.
In the mid-1970s, biologist L. David Mech extrapolated
the wolf densities from three study areas in Minnesota to the
known wolf range at that time and estimated a population of 1,000-1,200.
During the winter of 1978-1979 field personnel from several resource
management agencies were queried by the MN DNR. Their knowledge,
combined with results from four radio-tracking studies, resulted
in a state-wide population estimate of 1,235 wolves. This figure
persisted as the official population estimate for ten years. In
the early 1980s work by Mech, Steve Fritts and Bill Paul identified
areas of newly colonized wolf range that suggested range and population
were expanding to the west and south.
In winter 1988-1989, the methodology of the MN DNR's
1978-1979 survey was repeated, using an even larger sample of
natural resource agencies and personnel, as well as incorporating
geographic computer technology. As a check, a second method used
the well-established relationship between densities of wolves
and ungulates -- in Minnesota's case, deer and moose, to estimate
wolf numbers. Both methods estimated the wolf population at between
1,500 and 1,750. There were at least 233 wolf packs, with the
average pack size being five. This survey identified about 23,000
square miles of existing and potential wolf range.
The DNR wolf survey was repeated in the winter
of 1997-98, using an even larger base of natural resource professionals
and applying more advanced GIS technology. That survey estimated
a population of 2,450 wolves residing in a contiguous pack range
of about 34,000 square miles. A total of 385 packs existed in
the contiguous range, in addition to several west and south of
the "new" wolf range.
The successful recolonization of vacant wolf habitat
over a span of three decades resulted from high deer densities,
wolves dispersing from existing packs, and wolves colonizing new
areas. This has been documented in all wolf telemetry studies
done in Minnesota. All colonization of new areas has been done
by the wolves themselves, unlike some states where wolves have
been reintroduced by natural resource agencies. While some wolves
dispersed to new areas from the major wolf range identified in
1978, others dispersed from the very few scattered packs in north
central Minnesota that survived the bounty era. An example is
one pack that the MN DNR had ear-tagged or radio-collared from
1969 to 1980, which occupied a 100-square-mile area southeast
of Hill City. Besides being partly responsible for the eventual
startup of five neighboring packs, the Hill City pack sent dispersers
to Boy River, Walker, Hinckley and Baudette, distances ranging
from about 28 to 135 miles.
Populations of white-tailed deer, the main prey
of wolves in Minnesota, benefited from many mild winters and accelerated
timber harvests over the years. These factors, which reduce winter-caused
mortality and create more suitable habitat, allowed the deer herd
to increase most years, even in the main wolf range. In Minnesota,
each wolf takes the equivalent of 18 to 20 adult sized deer per
year on average. Based on this average, wolves kill the equivalent
of about 40,000 deer per year, compared to deer hunters, who have
taken 60,000-80,000 deer across the entire wolf range through
the 1995 deer season. But then, winters got much worse. The 1995-96
and 1996-97 winters set records for their severity, and deer numbers
decreased by about half. Consequently, deer hunters took about
25,000 deer (all bucks) in 1996 in the Minnesota wolf range, while
wolves, whose numbers remained unchanged, continued to take about
40,000 deer.
When prey populations fluctuate dramatically, predator
numbers usually follow, and wolf numbers stabilized (if not slightly
decreased) following the deer decline, albeit temporarily. The
winters of 1997-98 through 1999-2000 were among the mildest on
record, thereby allowing the deer and the wolf population to again
increase. By 1999, the deer hunter harvest had increased to 73,000
deer, and the wolf scent station index (DNR's annual index of
the wolf population) rose to a new record for Minnesota.
How many more wolves can Minnesota hold? And how
should wolves be managed? Wolf populations increased about 6%
annually in the 1970s, about 3% annually in the 1980s. All indications
are that those increases have continued during the 1990s, and
about 4.5% currently. Annual increases of this magnitude can be
equated to compounding bank interest in a savings account, and
doubling your money (or wolf populations) every 15 to 20 years.
Wolf range, as well, continues to increase. Much of the unoccupied
and potential range identified in the 1988-1989 survey, and even
many areas deemed unsuitable for wolves, now contain wolf singles,
pairs or packs. Some wolves are surviving in areas with higher
road densities (more than one mile of road per square mile of
area) and human densities (more than ten people per square mile)
than identified as critical to wolf survival in 1988-1989. Wolf
packs have even colonized Camp Ripley in Morrison County. Dispersal
continues to areas as distant as the west-central and south-eastern
part of the state, the northern Minneapolis/St. Paul outer suburbs,
as well as North and South Dakota. Thus, wolves seem to be adapting
more to humans and, perhaps due to more education about wolves,
humans are becoming more accepting of the wolf's presence. The
most wolves that the MN DNR believes Minnesota can sustain without
increased wolf-human conflicts is about 2000.
The 1992 Eastern Timber Wolf Recovery Plan established
a population goal for Minnesota of 1,251 to 1,400 wolves by the
year 2000. By the early 1980s, Minnesota had already reached that
goal and by the late-1990s had nearly doubled that number. With
the recovery of the wolf populations in Minnesota, Wisconsin and
Michigan, the U.S. Fish and Wildlife Service may soon reclassify
the wolf in these populations
For more information on the reclassification and
delisting of the gray wolf, visit the U.S. Fish and Wildlife Service Web site.
For an updated map of Minnesota wolf range, visit the MN DNR wolf information page.
