This is one of two wolves that wandered from the Grand Portage Indian Reservation to Isle Royale National Park recently/NPS.
A
pair of wolves whose home range is on the Grand Portage Indian
Reservation in Minnesota recently used an ice bridge to cross 14 miles
over Lake Superior to Isle Royale National Park, where they wandered for five days before returning to the mainland.
One of the wolves, a female, was wearing a radio collar that enabled researchers to monitor their travels. According to Seth Moore, director of biology and environment of the Grand Portage Band of Lake Superior Chippewa, on February 22 the wolves crossed the ice to Isle Royale National Park and on February 27 they returned to the mainland.
During
their wanderings, the two wolves were spotted by long-time wolf
researchers Dr. Rolf Peterson and Associate Professor John Vucetich,
both in the School of Forest Resources and Environmental Science at
Michigan Technological University in Houghton, Michigan. The two
observed and photographed the animals. They found their arrival tracks
on the north shore of Isle Royale, some activity at McGinty Cove, and
then a track about 1 mile North of Hugginnin Cove.
Then the wolves
followed the shoreline around the south shore to the northeast,
according to a release from Dr. Moore.
Their tracks
were picked up again on the north shore of Siskiwit Lake, then headed
southwest to Mud Lake, where they exited along the south shore, crossed
the thin part of Washington Island, where they made brief chase of a
cow/calf, and then headed straight across the ice at 330 degrees heading
for Pigeon Point.
The wolves returned to the Grand Portage Indian Reservation on February 27, said Dr. Moore. "These
collared wolves have provided insight into how this isolated population
has managed to maintain itself through cryptic or undetected
immigration events. The declining frequency of ice bridges between the
mainland and the island as a consequence of climate change gives rise to
concern of loss of genetic diversity of Isle Royale’s declining wolf
population," noted the biologist. "The concern about genetic diversity
comes directly from genetic measures and genetically-caused physical
defects. The loss of ice has ultimately reduced this precarious
connection with the mainland."
Dr. Moore has since 2009
been leading a study to determine wolf densities, pack counts, and wolf
diet on the Grand Portage Reservation. The Grand Portage Band of
Chippewa have been studying moose and wolf populations on the
reservation using GPS collaring technology for the last decade. The goal
is to determine how climate change is altering the ecological structure
of the Grand Portage Band’s boreal forest system.
The
wolf study has indicated that at least three and likely four packs of
wolves occupy the Grand Portage Indian Reservation. The largest pack is
comprised of nine wolves as observed by helicopter survey conducted
during the week of February 22, 2015. The collared wolf that traveled to
Isle Royale was captured in early February 2014 and came from a pack of
seven wolves that were feeding on a moose kill near the Pigeon River.
GPS readings allowed researchers to track the wolves' travels/Grand Portage Band of Chippewa.
Diet
studies conducted on Grand Portage wolves indicate that they eat moose
(50% of diet), deer (35%), and beaver (15%). Adult moose predation rates
have been low on reservation lands, but moose calf predation is very
high and may be contributing to low populations of moose on reservation
lands.
The Grand Portage Band has been studying moose
populations and causes of mortality in adult moose and moose calves for
six years. That research has indicated that brainworm is the leading
cause of death for collared moose (40%) followed by winter ticks (20%),
other health issues (20%); however, wolf predation only comprises about 6
percent of adult collared moose mortality. A related study to identify
calf mortality causes indicated that about 70 percent of newly collared
calves are preyed upon within the first two weeks of life, about half of
that predation is due to wolves.
Officials at Isle
Royale National Park, where it's feared the resident wolves will die out
due to a lack of genetic diversity, are developing and initiating a planning process
to evaluate how to manage the wolves, moose, and vegetation on Isle
Royale. In the meantime, the general public can provide comments on this
issue by sending an email to isro_wildlife@nps.gov.
Concerns of climate change causing a reduction in frequency of ice
bridges like the one used by these collared wolves have catalyzed these
discussions.
The Grand Portage Band has a long history of using Isle Royale and has had claims to the land since prior to the treaty of 1842. "Clearly,
both humans and animals used the ice bridges historically and Grand
Portage Indians subsisted on moose, woodland caribou (prior to arrival
of moose), moose, and many fish species – lake trout, whitefish,
herring, sturgeon, suckers, and brook trout," said Dr. Moore. "Grand
Portage people also went to 'Minong' –their name for Isle Royale—to make
maple sugar and gather plants for food and medicinal purposes.
Portagers also trapped furs (otter, marten, beaver) through time and
collected stones and copper found in a near 100 percent pure state."
Wolf 13264* Captured and collared on February 3, 2014* Female, weighed 62 pounds, had approximately 50% hair loss due to mange* Darted from a helicopter, immobilized* GPS collared and released (4 hours data collection, three-year life span of collar)* Core home range is in Grand Portage and southern Ontario*Furthest distance across locations is 100 miles*Made multiple trips > 50 miles*Likely den site localization from 2/12/14 to 3/13/14* Returned to den multiple times over this time span* Traveled to Isle Royale 2/22 to the northwest side of the island* Traveled along of the west end of the island, following the Lake Superior shoreline*Traveled to Siskiwit Lake on 2/26* Left on 2/27 and is currently in Grand Portage
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