Two More Blog Entries by John Vucetich on the Wolves of Chippewa

March 8, 2012 

A Band of Boy Wolves

By JOHN VUCETICH

 

John Vucetich

 After a snowfall, wolves often walk in each other’s tracks.

 

John Vucetich, a wildlife ecologist from Michigan Technological University, leads the wolf-moose Winter Study at Isle Royale National Park.

Thursday, March 1

With strong evidence that the wolves of the West-End Duo are a mated pair, our attention is focused on the Chippewa Harbor Pack. Analysis of DNA in wolf fecal samples from moose kill sites indicate the pack had no more than two adult females in January 2011. We observed pups in the pack this past October. So, a reproductive female survived at least until those pups were weaned. Now, we are looking for reasons to think the pack includes at least one adult female that has survived this winter.

 

John VucetichRavens circle the Chippewa Harbor Pack, apparently traveling without a female, on Siskiwit Lake.

 

Sometime yesterday, the Chippewa Harbor Pack left the Moskey Basin kill site, headed south to Lake Mason, crossed Chippewa Harbor and continued on to Lake Whittlesey. But two of the six wolves — including the pup — remained at Moskey Basin. If the Chippewa Harbor Pack includes a reproductive alpha female this winter, she wouldn’t remain at the kill site. She’d be moving with the other wolves.

Don and I watch those four wolves this morning as they wake from a slumber on a ridge overlooking Lake Whittlesey. They continue down Whittlesey, cross Wood Lake and venture onto Siskiwit Lake. Of these four wolves, we know one is a male, and because he’s radio-collared, it is easy to keep track of his behaviors. He is typically submissive to other wolves. If there is an alpha pair, he’s not part of it.

That leaves three wolves. None offer any sign to suggest a mating pair is among them. The signs during mating season — usually late February — are pretty reliable in the sense that we’ve never failed to recognize the presence of a mating pair. If two of these three wolves were a mated pair, they’d walk together. Given the deep snow, they’d be moving single file, but his nose would be separated from her tail by no more than inches all day long. Occasionally, they’d put a few feet between themselves as he exerted some dominance over the other two wolves.

We see none of this, not previously and not today. Today, the four wolves are walking single file, more or less evenly spaced over 30 meters or so. The subordinate, radio-collared wolf is sometimes second in line and sometimes fourth.

Where wolves bed in relation to one another is another reliable sign. During the breeding season wolves in a mated pair typically sleep very close to each other, often touching. Other wolves typically sleep with a meter or more between them. Today, when the four wolves stop to rest at the northeast end of Siskiwit Lake, each beds five meters or so from its nearest neighbor. And that’s what we’ve seen all winter.

After observing the Chippewa Harbor Pack for a few hours, we fly west to spend some time looking for the West-End Duo. What greets us is a wall of snow just about to swallow the west end of Isle Royale. It’s time to return to the bunkhouse.

Friday, March 2

 

Rolf Peterson, left, and John Vucetich in their Winter Study gear.

 

Rolf and Don find the Chippewa Harbor Pack bedded on Siskiwit Lake about five miles down the shore from where we saw the wolves 24 hours ago. For the past two days, it hasn’t seemed as if they were hunting, at least not vigorously. They’re not even in an area with many moose. They haven’t been scent-marking, so this trip to the western end of their territory doesn’t seem to be about defending their territory, either, at least not vigorously. If a wolf pack could ever appear desultory, this is what it would look like.

Today’s observations offer no indication that a female is among them. Traveling without a female this time of year would make any pack desultory.

• March 7, 2012

For Moose, an Easy Winter Turns Hard

By JOHN VUCETICH

 

John VucetichIt’s hard work walking through snow, so moose often bed down for a nap.

Sunday, Feb. 26
We wake to 50-mile-per-hour winds and 10 inches of new, wet snow. The snow is quite a marvel, unless you’re the moose whose feeding is restricted because the snow is too exhausting to slog through. Most of the moose have been experiencing a relatively easy winter. The risk of being killed by a wolf is lower this year than any living moose can recall; the fir twigs are large and numerous, and the snow has been shallow all winter.
Until today. The snow is not catastrophic, just difficult. Do they wonder why they suffer? Do they linger a few moments longer before getting up again and then sigh before plowing through the snow for another bout of foraging? Moose certainly have thoughts, and some we understand — the fear of being chased by a wolf, the pleasure of eating fresh blue-bead lilies in the spring. But our knowledge about the content of most moose thoughts — thoughts that are as real as any of my mine — lie at the fuzzy boundary between inference and imagination.

Monday, Feb. 27

To our surprise and their good fortune, we observe the Chippewa Harbor Pack feeding from the carcass of an adult moose they recently killed — probably the day before yesterday. They killed it less than a mile from the last moose they killed, which had been a calf. And a couple days before that, we observed the Chippewa Harbor Pack chasing a cow and her calf. Both moose had blood on their legs. So today, the Chippewa Harbor Pack may well be chewing on the bones of the calf’s mother. They’ve had as much food in the past five days as they’ve had in the previous three weeks.
I’ve watched these wolves and their ancestors for seven weeks each winter for a decade. Rolf and Don have done so for several more decades. It’s no small effort, but it provides just a glimpse of their lives. Last month, the Chippewa Harbor Pack was on track for one of the lowest kill rates we’ve ever observed. But this week and next their need for food will be reasonably well satisfied. Was last month just a tough stretch in what otherwise were pretty good times? Or were these past few days just a brief reprieve from generally tough times? I suspect the latter, but I’m not entirely certain.

It’s a kind of uncertainty that routinely follows long-term observations. You watch for some time, get a sense of how it might be, and then you see something completely different. What’s normal — what you saw before or what you see now?

During the first two decades that scientists observed the wolves on Isle Royale, the predators had a very strong influence on moose abundance. Then climate replaced the influence of wolves over the next two decades. Understanding nature and the lessons of long-term research may require adjusting our sense of what counts as normal.

 

Rolf PetersonCow and calf injured by the Chippewa Harbor Pack.  The wolves fed on the carcass of the cow.

 

Tuesday, Feb. 28

Most days in the past month have been some variation of snow, wind or both. Some days we get going early in anticipation of being shut down by midday. Other days we wait, looking for early signs that the winds or clouds are about to grant a reprieve. Our lives are governed by subtle shifts in how the wind and clouds pass over Lake Superior. Today, we are granted an afternoon flight.
The Chippewa Harbor Pack surprises us again. They are near their same kill site — 50 meters from shore, near the head of Moskey Basin. But this time there are six wolves. During every observation since Feb. 4, we’ve seen only five wolves. We presumed the sixth wolf had died or dispersed; we guessed death.

Comparing photographs from previous flights with those taken today suggest that the missing wolf was the smallest, likely a pup. It’s not uncommon for pups to stay behind, maybe near an old kill, while the rest of the pack travels.

Don and Rolf find only tracks of the West-End Duo on the south shore near Long Point. But this country around Long Point is home to quite a few moose. If they kill one near here, they’ll remain in the area for several days, and we might learn about it later.


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