Wolf Country
Page 17
At noon we drove to the airfield and found Graham and Hank lying listlessly under the wing of the plane. Graham was showing the effects of the motion-sickness pills, and Hank appeared fatigued from the flights. The data we were getting were good though, and we decided to carry on.
By mid-afternoon the ceiling lifted enough for us to fly. Mary and I went along to see the rendezvous site from the air. Beyond our left wing the Bonnechere River snaked through the hills. We flew over the wounded forest behind our camp and could see a pair of bulldozers knocking down trees and a log skidder crawling into a landing. There was the conspicuous hydro line, our tent, and the rendezvous site.
The pack had chosen a system of linked beaver ponds connected by marshes and meadows that were invisible from the ground. Dead standing trees dotted the largest pond, victims of recent beaver flooding. Like other rendezvous sites, this one had its resident beaver. In the early 1970s, we determined from scat analysis that wolf scats collected at such places showed more beaver than those collected on trails and roads elsewhere. Wolves exploit their local resources.
After a few circles we began tracking signals. Like chess players, the Grand and Foys wolves had again made strategic moves relative to each other. All but Foys 2 were absent from the rendezvous site; he had returned after a seventy-two-hour absence.
After the flight, Mary and I drove back to our tent and confirmed from the ground that Foys 2 had indeed come back. A few hours later, on the evening flight, Graham radioed that Foys 4 had moved to the same little hilltop bog where Grand 3 had been the previous morning. It was the same hilltop bog where we had watched the seven Foys wolves the winter before.
That night we sat up late to monitor the rendezvous site. Only Foys 2 was on the air at first, then sometime between 1 and 3 A.M. Basin 3 Foys and Foys 4 returned. At 4:25 A.M. we were woken by a full chorus of howling, the first vocalization in three nights. Voices blended and the air was suddenly filled with sound that reverberated off the hills. When Mary checked the signals, Foys 4 was so close that the receiver picked up his signal even before she plugged in the antenna. He was with Basin 3 Foys on the hydro line less than one hundred metres away. Foys 2 was farther back.
The pack howled at 5 A.M. and again just after 6. We made radio check and found all collared wolves had gone. Something was up. Another pack howl at 6:25, this time initiated by a distant single to the east. The single kept howling after the pack stopped, repeating high-pitched, dropping howls for a few minutes.
After the morning flight, we left to search the hilltop bog for signs of any encounter between Foys wolves and Grand 3. When we climbed out of the canyon and crested the ridge, we heard no signals. No wolf sign — no tracks, scats, broken branches. No carcass. We searched for over an hour. Wolves come and go like phantoms. But trespassing Grand 3 must have left some scent, attracting the attention of the Foys wolves.
Grand 3, a member of the Grand Lake pack to the north, had been collared as a yearling female the previous summer. She had stayed with her natal pack most of that winter, then began pre-dispersal movements to the northwest. Although she returned briefly to her territory in late March, we did not record her with her packmates again. By early summer she had moved southwest and had begun defining a new territory abutting the Basin-Foys pack’s land. At times she clearly trespassed, but despite the Basin-Foys pack’s large size, it gave ground.
Grand 3 likely was not alone in her search for land, but we cannot be sure. A month after our flights ended, we captured Basin 4 McDonald, the largest collared wolf in our study. He was in the area occupied by Grand 3. After that, these two wolves usually were together and formed the beginnings of the McDonald Creek pack.
At the rendezvous site that night, the Foys Lake wolves gave us five more serenades, and we noticed a correlation with their movements. Every time they howled, either one or more collared wolves had just returned or left. In contrast, every night but the previous one, wolves had entered or left with no howling. This is consistent with our experience with other packs: some nights are silent, others filled with howls. The difference may relate to hunting success, or to a decision to change rendezvous sites, or to trespass, or some wolf social event.
The series of flights ended the next day, but Mary and I stayed at our camp. By early August we were locating the wolves more commonly to the east. We began a second block of flying, and Graham pinpointed a new rendezvous site in a boggy hollow so close to a logging road that the dust from the logging trucks at times must have reached them. Each evening after the loggers left, the wolves would leave their footprints on the tire tracks and around the skidders parked for the night.
What had attracted the pack to such a place? Probably deer, themselves attracted to the good browse provided by the crowns of the felled trees.
On calm nights we tape-recorded the pack whenever it howled. The Foys wolves were beautiful howlers with deep, resonant voices, high, dropping voices, sonatas, concertos, full orchestras. As August wore on, their howling increased.
The pack was still there by the logging road late in the month when we had to break camp and end the field season. By then we had much of the information we wanted.
These data indicate that for four days the pack was feeding on a moose at a bog edge ten kilometres from the rendezvous site. Foys 2 and Foys 4 were in on the carcass first, stayed there for fifty-two hours, then left to alert other pack members. Foys 4 met Foys 1 four kilometres to the north and led him to the carcass. Foys 2 returned to the rendezvous site, where he met Basin 3 Foys and led her there too. All four collared wolves stayed at the carcass another twenty-four hours when our block flying ended. Foys 2 and Foys 4, instead of hogging it all for themselves, which would maximize their individual fitness, gave up some food for the good of the group.
That type of cooperative behaviour is explainable as “reciprocal altruism”: you scratch my back and I’ll scratch yours. It is worth sharing my kill with you if sometime later you share yours with me. The pack seemed to be operating to maximize its chances of making kills. Never were all five collared wolves together during our monitoring. Instead, they hunted in three loose parties. Occasionally, individuals moved from one party to another.
The pups waiting back in the rendezvous site for food would approve of what the adults were doing. Three parties were out hunting, not just one, and they were searching their entire territory. In one-quarter of our recorded fixes, the collared wolves were between twelve and eighteen kilometres apart, much of the diameter of the territory. Maybe they were having to work hard to find prey, or maybe wolf mobility is so great that they cover their whole territory with ease. Nevertheless, because of their hunting tactics, most of the deer, moose, and beaver in the territory were liable to be found every day. The pack seemed to be operating as a cooperative team.
At the same time, pups would be glad that the adults were keeping an eye on them. Collared wolves were in the rendezvous site for 19 per cent of the seventy-eight fixes. The baby-sitting task was shared; all wolves were there on occasion. Basin 3 Foys and Foys 3 stayed closest to the rendezvous site. Foys 3 was especially attentive to the young. His average distance away was only 4.1 kilometres, and even that is an inflated value because of one brief trip seven kilometres to the west.
Later, genetics showed that Foys 3 was the grandfather of the pups. Basin 3 Foys was his daughter, and she was, as expected, the mother of the pups.
Different wolves appeared to be playing different roles in the pack. Foys 2 and Foys 4 were more closely associated as wide-ranging hunting partners, although near the end of our monitoring session Foys 3 and Foys 2 made a short trip together. Foys 1 associated with the other wolves only at the moose kill and on one visit to the rendezvous site. He appeared to be more of a boundary patroller, averaging 8.1 kilometres from the rendezvous site, greatest of them all. He moved more than other wolves too, averaging 4.5 kilometres between fixes compared with the least active wolf, Foys 3 at 2.5 kilometres. Oddly, despite Foys 1’s a
pparently limited interest in the pups, genetics showed that he was their father.
Division of labour is a hallmark of advanced societies. So is reciprocal altruism expressed by food sharing and cooperative care of the young. So is group hunting, the social characteristic that best defines wolves. The Foys Lake pack showed them all.
When we look through our winter data, all the collared Foys wolves were together for half the recorded fixes. Several wolves can subdue adult ungulates more effectively than one or two. Similarly, when coyotes turn to larger prey, they tend to hunt in groups, as observed in Yellowstone National Park, where, without wolves present, coyotes broadened their prey base to include adult female elk. Coyotes, or coyote/wolf hybrids, form packs in the New England states and Maritime provinces too, where in winter they prey on white-tailed deer.
Mary, Graham, and I followed the Foys Lake pack one December day, with only a few centimetres of snow on the ground. The wolves travelled in single file through dense lowland conifer, then along a narrow stream running between cattails to a bog where they finally fanned out. Thirteen tracks arched over to a beaver lodge. Some wolves climbed up and dug at the breathing hole, but a lodge cemented with frozen mud is wolf-proof.
The Foys Lake pack was travelling as a unit too, on February 22, 1990, when Graham spotted twelve of them from the air. That was at 8:50 A.M., only two hours after we had seen them from the Achray parking lot trespassing on the ice of Grand Lake. They had travelled up a chain of small lakes along their northern boundary, covering approximately nine kilometres at four and a half kilometres per hour in deep snow.
The entire pack was together on a February afternoon as we followed their signals along the Bonnechere River. In successive survey flights, Graham had picked up Foys radio signals coming from the same patch of spruces along a nameless little creek. We struggled through snow-catching conifers, one wolf howling ahead of us, another to the right. More joined in — one behind, one ahead — tuning up for a two-hour concert among the best in our experience. Theirs were long, expressive howls, rising and falling in uneven steps. At dusk we reached the carcass they were feeding on. The usual black avian cloud lifted off to reveal an almost entirely consumed moose.
While we hacked off the bones we needed, wolves kept howling from all sides, long, beautiful, deep-throated howls. We started back, able to follow our snowshoe tracks without a flashlight. For more than an hour we shuffled along, the temperature dropping, pinpricks of starlight shining through the branches overhead. The wolves escorted us all the way, howling every few minutes, never close enough to hear in the brush, often half a kilometre or more away.
The remaining half of our winter fixes showed the Foys Lake wolves travelling as singles or in small groups. But if their movements were coordinated, this can be interpreted as group hunting too. Packs split into several hunting groups will detect more prey. As long as groups can locate each other, as they seem able to do, splitting up may represent a more efficient hunting strategy. Even when wolves seem to be alone, they may not be out of touch, like two people shopping together in a grocery store who go down separate aisles but know they can find each other easily. Hunting wolves may be a few kilometres apart, but their paths cross periodically so that they are really hunting together. The wolves’ world of scent and their mobility may make a grocery store out of a seemingly extensive landscape.
Reviewing winter movements, travel as a pack may be necessary when deep snow increases the energetic costs of wolf travel, although we recorded it in shallow snow as well. Elsewhere, where prey are more sparse and wolf territories larger, wolves may have a more difficult time relocating one another, causing them to travel as a pack more often. Or, when hunting caribou on the tundra or elk on grasslands, whole packs may be strategically more successful than individuals in chasing, flanking, and cutting off prey, although small groups have been shown to do well too. Or, if prey is difficult to kill, it might be best hunted by packs; small wolves in an already small subspecies such as the Algonquin wolf may benefit from numerical strength to subdue a healthy moose, one unencumbered by snow.
The best test of pack coordination, even when wolves are spread across a landscape, is whether they all find and feed at each other’s kills. While we have yet to calculate an exact percentage, all collared pack members have been present at most of the one hundred or more prey carcasses we have located. That they find each other is convincing evidence that they are cooperating in the hunt even when seemingly apart. That describes a supra-organism.
If survival of the most fit pack is a valid idea, what constitutes pack fitness? A “most fit” individual, in purely biological terms, leaves the most offspring to survive and reproduce. A “most fit” pack will do the same. An obvious requirement for both is plenty of food.
The Foys Lake wolves claimed the largest territory in our study, approximately 275 square kilometres, probably larger if we had located them more often. If prey are distributed evenly across the landscape, more land means more prey. The Foys Lake pack held title to most of the broad Bonnechere Valley inside the park. Flanking packs — Ryan Lake to the south, Redpole Lake to the west, Grand Lake to the north, McDonald Creek to the northeast and east — gave it room, willingly or otherwise.
Probably not a coincidence, the Foys Lake pack also was the largest pack. Larger packs will have more hunters searching more places. A large pack also increases the possibility that especially skilled hunters may be among its members. However, more wolves in a pack means more mouths to feed, so a larger territory may not necessarily result in more food per wolf. We, like others, have not had continuous contact long enough or often enough with packs of different sizes to be able to compare their kill rates.
Large packs may not be more fit if the reason they are large is simply a lack of opportunity to disperse, such as on an island like Isle Royale. Nor do large packs necessarily reflect greater fitness if they only result from more room to feed around larger prey, as sometimes suggested, such as around the carcasses of the large subspecies of moose in northwestern North America or bison in and around Wood Buffalo National Park.
Large wolf packs are not analogous to large packs of African wild dogs and spotted hyaenas, which can contain up to fifty animals. These species have a problem that wolves do not: they must defend their kills against other species of predators, especially lions. Even lions have large prides to overcome the problem of displacement at carcasses.
The reason that the Foys Lake pack was so large may have been simply that there were two breeding females. Only in one other pack have we recorded more than one breeding female. Dave Mech in Minnesota describes roughly a 15 per cent incidence, higher than in our study. Normally, social hierarchy works against multiple breeding.
Large packs, then, may or may not signal greater fitness. We assessed the idea, but it comes out inconclusive.
Evidence of competition between packs — staking out and holding land that other packs want — supports the idea of supra-organism and survival of the best-fit pack. We witnessed passive competition in the delayed boundary skirmishes between the Foys Lake wolves and the newly forming McDonald Creek pack represented that summer by Grand 3. That winter, Grand 3 and Basin 4 McDonald were usually together right on Foys Lake pack’s northeastern flank. They had succeeded in taking over about twenty square kilometres of land that the Foys pack had occupied the winter before. How two wolves managed to wrest land from twelve wolves is unclear, but the shift in boundaries did occur. Maybe Grand 3 or Basin 4 McDonald were related to other Foys wolves that were not collared and so escaped our genetic analysis. If so, the territory adjustment may have been made with consent. The McDonald Creek wolves expanded their new territory later, only after the Foys Lake pack was killed.
We have other evidence of passive competition between packs. In the summer of 1996, a collared wolf trespassing just inside the Jocko Lake pack’s territory was stationary by a bog while a wolf from the resident pack approached on a trajectory that would brin
g them into close proximity. The approaching wolf was still one and a half kilometres from the stationary wolf when the stationary animal suddenly moved off and within minutes was out of signal range. Nineteen minutes later, when the approaching wolf was exactly one kilometre from where the stationary wolf had been, it swerved abruptly and went to that exact spot. The incident suggests that detection may have taken place more than one kilometre away. Here was a possible case of avoidance on a territorial boundary, passive defence.
More dramatic, of course, are other examples of trespass resulting in killing, such as the Nahma wolf, Travers 8, probably Pretty 6, and, later in the story, Pretty 7. One must conclude that wolf packs live in a situation-specific world that embraces mutual acceptance, avoidance, competition, and vigorous defence.
Being fit ultimately did nothing to prevent the demise of the Foys Lake wolves. Natural selection had tuned them up to survive in nature, not for what occurred.
Events began to turn against them on November 15, 1990. Foys 2 was shot by an archer less than one kilometre from the park’s eastern boundary. Basin 3 Foys died the following March — one bullet straight through the heart in a woodlot outside the park.
Only a few weeks later we tracked Foys 3 on mortality mode to a bare spot of ground beneath a large spruce. His trail was unusual; he had been dragging his hindquarters in the snow. Branches and sticks lay broken around his body. He tested positive for rabies. So did Foys 4, picked up two weeks later by Lee and Tom.
That summer we could find no evidence of a Basin-Foys pack. Foys 1 seems to have been a lone wolf in August when Jenny and Carolyn recollared him. He was alone in early December on Graham’s flights.