The following are field reports from the 2007 Isle Royale wolf study.
The Saga of Alpha Female 410
By Rolf Peterson
On our first research flight over Isle Royale in 2007, the radio signal from alpha female 410 in the Chippewa Harbor Pack was on mortality mode. The next day we recovered her radio collar and skull from a heavily scavenged site on the north side of Angleworm Lake, and in the next week the East Pack made regular forays to the site. The East Pack had probably killed 410 as she died on the disputed territorial border between the packs, much as the Chippewa Harbor alpha male died in February 2006. The story of 410 and her mate is one of the most dramatic tales coming from over four decades of wolf research on Isle Royale. We think of it as an unusually compelling story, but probably all old wolves would have an equally unlikely story—if we only knew.
On 16 February 1999, we followed the running tracks of the Middle Pack for six miles as they chased a foreign wolf. We caught up to the 11-member pack at water’s edge just before noon, vigorously shaking themselves dry, while 20 feet out in Lake Superior—standing on a submerged rock in 10 inches of water—stood a bedraggled wolf, cowering, its hindquarters almost underwater.
During the next hour we circled overhead. After several minutes of rolling in the snow to dry off, the Middle Pack wolves either lay in the snow, watching the victim in the lake, or strutting stiffly back and forth along the shore in front of the hapless wolf. Suddenly, in quick succession, three wolves jumped into shallow water and leaped for the rock where their quarry stood quivering. Confronted by this snarling trio, it fought for its life, snapping furiously toward the lunging pack members. The lone wolf was forced backward into neck-deep water, but it retained its footing and held the attackers at bay; they retreated to shore to shake and roll again in the snow.
The lone wolf lost this battle, and was left for dead on the icy edge of Lake Superior. But a trailing male from the Middle Pack showed up and took an interest in the motionless victim, which turned out to be a female wolf in heat. Before the day was out the female managed to rise and make it 50m into the forest, where she lay all night as her bleeding wounds stabilized. The next morning we found that the male and female had walked out of the immediate area, and we picked up a few hairs from her bloody bed. Five days later we found the pair a half-mile from the attack site, the female standing shakily while the male alternately licked the wounds on her neck and frenetically tried to court the female.
The following summer a pup was born to the pair and the Chippewa Harbor Pack was established. Within two years this pack had killed two successive alpha males in the adjacent East Pack as it systematically took over a moose-rich portion of east end of the island. The savior male and courageous female thrived, reproducing each year and emerging as a territorial powerhouse. We radio-collared the female in 2003, and DNA from her blood matched that from the hair recovered from the attack site in 1999.
The East Pack and Chippewa Harbor Pack both flourished as long as there were plenty of moose. But by 2006 the East Pack had run short, and it began to make inroads on the edges of Chippewa Pack territory. In February 2006, the East Pack moved in on a recent kill of the neighboring pack. Finding the Chippewa alpha male feeding, the East Pack promptly killed him. Female 410 was then at greater risk, but she recruited a new alpha male, mated, and raised another litter of pups in 2006, her seventh successful season of reproduction. Against impossible odds, she survived and carved out, by wolf standards, a highly successful life. Her canine teeth were worn to small stub, one canine tooth was badly infected and loose and in the end life was simply wrung out of her.
Rolf Peterson has been the leader of the Isle Royale wolf-moose study since 1975.
A Small Safe Haven
By Leah Vucetich
June 5, 2006. I was awakened to the sound of moose grunts outside the yurt where we live during the summer on Isle Royale. My alarm had not gone off, so it had to be sometime before 6 a.m. I was not prepared (mentally or logistically) to make observations on the foraging behavior of this moose. However, I can’t seem to resist the sound of those burdened grunts! You cannot make these observations when you want; they have to be made when a moose decides to share its time with you.
So I crawled over my comatose husband, John Vucetich, and sprung out of bed. I pulled my baggie field pants on over my long sleeping undies, zipped on a fleece, and slipped on my red Crocs. Later, I realized that I had pulled my field pants on backwards. I dug my binoculars out of yesterday’s pack and grabbed my notebook.
A cow moose was right outside the yurt near the Park Service junkyard, foraging busily. The early morning light was dim, so making observations was difficult. And as she moved deeper into the forest, I realized I was being swarmed with mosquitoes and blackflies. I had forgotten an essential piece of equipment—my bug shirt. I noted her position and line of movement and headed back to the yurt. I changed into socks, boots, baseball hat, gloves and citronella spray and headed back out. Despite the ruckus, John showed no signs of awakening.
I listened, but heard nothing, so I proceeded carefully from where I had last seen her. Then I heard the crack of a hoof on a twig, and the methodical munching of leaves. As the morning light became brighter, I noticed her pattern of hair loss (caused by winter ticks). The pattern was different from those I had seen this year. This apparently was our first meeting. Then I saw something I recognized—a tear on her left ear. I had met this moose two years before. In the summer of 2004, she and I had spent quite a bit of time together. She had a calf, and I helped a German film crew videotape her at a nearby mud lick.
It was great to see an old friend, and it made me smile to know she was still doing well. She now carries a tumor on her right shoulder (these skin tumors are common and typically benign). I think that’s new since we last met (I’ll check my notes).
She continued to forage and I continued to record. She is a moving browser—no standing in one spot and gorging. She takes a few steps and a few bites and a few steps. I’m sure this works for her, but it does make recording a challenge. This morning she eats lots of yellow birch leaves—both from branches on tall trees and from small suckers. Each birch bite is nearly matched with bites of lady fern and Dryopteris ferns, and supplemented with a hazel leaf here and a maple leaf there. After some time she began moving a bit more quickly—too quickly for me to handily follow, observe, and write notes. It is amazing how swiftly moose can move while appearing to be meandering casually. I was disappointed that she was getting too far away from me.
Then she stopped suddenly and looked intently into the forest beyond her. She stood stock still for several seconds, then turned and bolted straight for me. In an instant, I felt that she was not charging me or displaying any type of aggression but was beating a rapid retreat from something she had heard, seen, or smelled ahead of her. She trotted toward me—800 pounds of brown fur and muscle—and then past me, just an arm’s length to my left. She spun around, and I could feel her looking over my shoulder.
There we both stood, peering intently into the forest. Then I saw it—a fleeting glimpse of the dark form of a wolf as it ran through the trees just beyond where she had been standing.
After her danger had passed, we stood near each other for what seemed a long time—perhaps two or three minutes. We examined each other carefully, and I asked if she remembered me from the mud lick. She leaned toward me, sniffing with ears cocked forward, and I stretched out my hand. She decided to move past me, and foraged a bit more. She never stopped looking where she had seen danger and was no longer relaxed and leisurely in her foraging. After a couple of minutes, and just a few more bites, she left the area, walking too quickly for me to keep up.
I had been excluded from her moose world and was back into my own. But where exactly was I? I had no map, no compass, no GPS and no glasses or contacts, no sun, and had been on a moose trajectory through the forest. I decided to first look for tracks that may have been left by the wolf, but found no appropriate substrate to record the passing. I began to walk in the direction I thought was home. Eventually, I returned to the yurt, where John was still groggy – hadn’t heard the alarm, didn’t even know that I had been out, and had no idea that a moose decided that I was the safest thing to put between her and a wolf!
Leah Vucetich is the wife and research assistant of John Vucetich, a population biologist at Michigan Technological University and Rolf Peterson’s partner in the ongoing Isle Royale wolf–moose study.
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