Refuge Notebook
Peninsula Clarion Article
Dated
03 December 1999
 Wolves
on the Kenai National Wildlife Refuge
by Liz Jozwiak
in collaboration
with Ted Spraker
The wolf represents different things to different
people. Some value the wolf as a symbol of the Alaska wilderness and as an essential
part of the natural wild landscape. Others consider the wolf a game animal, like
other furbearers which are harvested for the value of their pelts. Some people
view wolves as aggressive and unpredictable predators, against which their children
and livestock must be defended. People may not have strong opinions about voles,
but they generally have something to say about wolves!
On the Kenai National
Wildlife Refuge we monitor wolves with the goal of keeping a healthy sustainable
wolf population. In cooperation with the Alaska Department of Fish and Game (ADF&G),
we attempt to resolve occasional predation issues, and to educate the public about
Kenai Peninsula wolves, their movements and lifestyles.
As most Peninsula
residents know, wolves and other carnivores such as lynx, coyote, brown, and black
bears are native residents of the Kenai Peninsula. But the history of wolves on
the Kenai is a story in itself. Early records indicate that wolves were commonly
observed on the Peninsula in the late 1890's about the time a gold rush brought
prospectors to the area. By 1915, wolves were almost completely exterminated from
the Kenai Peninsula because of predator control programs using poison, along with
heavy hunting and trapping. Then in the early 1960's wolves began to repopulate
the Peninsula. It is still a mystery whether most of the recolonizers dispersed
from the mainland, or whether a few of the surviving lone wolves (whose tracks
were sporadically sighted between 1935-1950 by trappers and biologists) were the
seed crop of our present day Kenai wolf population. Recent DNA studies revealed
that the Kenai Peninsula wolf population is genetically similar to mainland Alaska
wolves. This suggests that there may be a low level of mating between Kenai and
mainland wolves through occasional migrants from the mainland or that the Kenai
Peninsula wolf population has not had enough time to develop unique genetic characteristics.
Since 1976, Refuge and ADF&G biologists have radio collared almost
200 wolves in the northern portion of the Refuge in an ongoing effort to learn
more about their predator-prey relationships, pack size, territory, genetics,
and susceptibility to disease. This is one of the longest monitored wolf populations
in Alaska. Some interesting findings came from an early study (1976-1981) when
3 to 7 wolf packs were monitored by Rolf Peterson from Michigan Technological
University. Rolf estimated the territory size of wolf packs averaged 255 mi2,
wolf density averaged 7 wolves /1,000 mi. 2 on the northern portion of the Kenai
Peninsula, and he determined that the Refuge wolf population was largely regulated
by human harvest. Rolf found that a wolf pack in winter consumed 1 moose / pack
/ 4.7 days when moose densities were high within the 1947 burn habitat. Most of
the moose consumed by wolves were old, suffered from debilitating conditions,
and were more vulnerable because of average to above average snowfall during the
study period. Wolf predation on moose appeared to be much less between May and
September. Wolves are by nature a resilient species, and as long as they are free
from disease, and their food supply remains plentiful, the population can sustain
a harvest of up to 40%. However, when harvests in the late 1970's exceeded 40%,
wolf densities declined the following years.
Hunting and trapping pressure
has declined from the highs of the 1970's and early 1980's. As part of my Masters
Degree research, I looked at how wolves responded to different levels of harvest.
Logically, if wolf densities declined after years of high harvest, one would expect
their numbers to go up after years of low harvest. I analyzed 10 years of wolf
telemetry and harvest data between 1982 and 1993, expecting to see wolf densities
increasing after several years of low trapping pressure. I was surprised to find
just the opposite: wolf densities did not increase in years when very few wolves
were trapped or hunted. Instead, wolves dispersed from packs more frequently when
the harvest was low. I also found that a greater proportion of juveniles (1-2
year olds) dispersed than did pups or older adults. Dispersal however has its
costs. Dispersing wolves have about half the survival rate of those which remain
with their packs. Generally, dispersers have a higher probability of being killed
by other wolves or being harvested by humans.
The higher dispersal rate
after years of low harvest may be just one factor among several that have affected
wolf densities in recent years. Disease and parasites also play a roll. Blood
samples over the last 15 years indicate that many adult Kenai Peninsula wolves
are experiencing higher exposure to canine parvovirus or to canine distemper virus.
Parvovirus is likely to kill wolf pups before they are 3 months old, and is believed
responsible for lowering wolf numbers in winters in Minnesota. Lice appeared in
wolf packs on the Kenai Peninsula in the early 1980's, most likely from contact
with feral domestic dogs, and this parasite is still present in the population.
We don't know exactly how many wolves there currently are on the entire Peninsula,
but Rolf Peterson estimated the wolf population in 1980 at approximately 186 wolves,
however a Peninsula-wide wolf census is needed to obtain a current estimate.
Recently
we have been able to examine a second wolf population using ADF&G's 1998 relocation
of 18 wolves to the Kenai Peninsula. These wolves were removed from Interior Alaska
near Tok as part of the State of Alaska's Forty Mile Caribou Management Plan.
Relocating wolves is an extreme case of dispersal because individuals are not
simply taken out of their packs but are moved a great distance into new territory.
As in most relocation programs, 50% mortality was expected in these transplants.
It was higher in the Kenai case, with 78% mortality after a year and a half. Of
the 18 wolves released, 8 were harvested, 5 died of unknown causes, and one was
apparently killed by a moose. Four translocated wolves continue to be monitored
by biologists the Kenai NWR and ADF&G: the two females are together in a pack
of about nine wolves, whereas the two males appear to be loners.
Two of
the introduced wolves achieved the remarkable feat of escaping from the Kenai
Peninsula. Female #94 traveled over 200 miles northward in the first month and
was radio-tracked to the Knik glacier east of Palmer. One of the males was harvested
just north of Talkeetna last winter. These kind of directional homing movements
towards their release locations, also reported in other translocation studies
in Michigan and Minnesota, may be one of the most interesting results of such
experiments.
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Liz Jozwiak
is a wildlife biologist at the Kenai NWR. She recently completed her Masters Degree
at Colorado State University where she analyzed the effects of varying harvest
levels on the Kenai wolf population.
Ted Spraker is the Area Wildlife Biologist
for the Alaska Department of Fish and Game on the Kenai Peninsula. He has a Masters
Degree from the University of Wyoming.
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