Ecological Studies of the Timber Wolf in Northeastern Minnesota

Part 3

Chapter 34,028 wordsPublic domain

However, on April 17, 1051 was back in the general vicinity of the kill, and he and another wolf were resting on an open hillside about 100 feet from each other. As we descended for a closer look, the smaller animal arose and headed to the larger, presumably 1051 because he had not been disturbed by the aircraft. The larger wolf did not arise for several seconds, but eventually followed the other into the woods. No tail raising or other expressive posturing was seen in either wolf. One week later 1051 was 26 miles northwest of the kill traveling alone.

Wolf 1053 was never seen less than 80 yards from another wolf, and there was no evidence that she ever associated with a conspecific. Even when she was seen 80 yards from the other wolf, both were resting, and when the strange wolf left, 1053 made no attempt to accompany or follow it.

No. 1055 apparently had been traveling with another wolf when caught on January 5, and tracks showed that the individual had remained near her until we arrived to handle her. Tracks found on January 7 and 10 suggested that 1055 was with another animal, but that animal was not seen during any of the six times 1055 was observed through February 1. However, from February 5 to 19, 1055 was with another wolf on eight of the 12 times she was seen. The two animals were observed resting, traveling, hunting, and feeding together. On February 20, and thereafter, 1055 was alone all 14 times she was seen.

It is possible that 1055's associate was killed between February 19 and 20. About March 6, a 63-pound male wolf pup was found dead (by Mr. Charles Wick, USDA Forest Service) within about 50 feet of a highway and less than a mile from where 1055 and her associate were seen on February 19. Because of the snow conditions, it was judged that the wolf had been killed (probably by an automobile) sometime in February.

Wolf 1057, whose foot froze during capture, was a member of a pack of 10 to 13 wolves, and was seen with the pack on January 13 and 18. After that she was usually found alone, although on at least five occasions she was with one or more wolves:

_No. of_ _Period_ _observations_ _Associations_

Jan. 13 1 10 other wolves Jan. 14-17 1 None Jan. 18 1 10 or 11 other wolves Jan. 19-29 2 None Jan. 30 1 1 other wolf Jan. 31 to Feb. 2 2 None Feb. 3-4 2 2 other wolves Feb. 5 1 1 other wolf Feb. 6-13 6 None Feb. 14 1 3 other wolves Feb. 15-22 5 None Feb. 23 1 10 to 13 other wolves Feb. 24 to Apr. 24 6 None

February 23 she was with the pack at a kill in her usual area, and although the pack left that night, 1057 remained near the kill the next day. Presumably this animal would have traveled with pack if she could have.

No. 1059 was part of a pack that included three to five members (fig. 26). From January 25, the first time she was observed after release, through April 2, the animal was seen 19 times with two other wolves, eight times with at least three others, and eight times with four others. She was never seen alone until April 17; both times after this when she was seen, May 9 and 21, 1059 was also alone.

Some insight into the fluctuating size of this pack was obtained on February 27 when the five animals were followed for 2 hours. During that time two members (one of which was larger than the other) often lagged behind the other three by as much as a mile. These two romped and played considerably, with one carrying a stick or a bone part of the time. Eventually they caught up again to the other three. The behavior of the two lagging wolves would be consistent with the hypothesis that they were either pups or a courting pair of adults. In either case, they seemed to be an actual part of the pack even though they temporarily traveled separately.

The fact that 1059 was observed traveling alone three times from April 17 to May 21 may be further evidence that the pack had a den in the area at that time. The presence of a den allows individual pack members to venture off singly and return each day to a known social center, as Murie (1944) observed, so they do not need to travel with each other to maintain social bonds. Wolves in our area breed during the latter half of February (see below), and the young should be born in the latter half of April. Since dens are prepared a few weeks in advance (Young 1944), pack members might be expected to begin traveling singly in mid-April.

Some information on social relations within our radiotagged pack of five was also obtained. One of the members could often be distinguished from the others by its reddish cast and this individual appeared to be the pack leader or alpha male (Schenkel 1947). In urinating, this animal lifted his leg, a position seen almost exclusively in males. Except for only two temporary occasions, this animal always headed the pack, which usually traveled single file. The second wolf in line generally was noticeably small, possible a female, and the third wolf was twice identified as 1059 on the basis of sightings of her collar.

The leader often gained a lead on the other wolves, especially during a chase (see below), much as reported for a lead wolf on Isle Royale (Mech 1966a). Upon returning to the lagging members of the pack, this animal usually held his tail vertically, an expression of social dominance (Schenkel 1947). On two occasions he led chases against strange wolves and demonstrated the highest motivation (see below).

The leader was also the most active in his reactions when scent posts were encountered. Because the function of scent-marking behavior is still unknown, it is important that detailed descriptions of the natural behavior of free-ranging wolves around scent posts be made available (fig. 27). Thus the following excerpt from field notes by Mech dated February 27, 1969, is presented:

"When they [the three wolves] came to a small frozen pond, where the wolf trail [which they had been following] branched and there were some packed down areas, they became quite excited [fig. 28]. This was especially true of the reddish wolf. He nosed several spots, and scratched around them. Usually his tail was vertical. He defecated at one spot, and right afterwards another wolf did. After about 2 minutes that pack went on.

"About 15 minutes later the 2 'satellite' wolves arrived at this spot, hesitated, nosed around but continued on after less than a minute.

"The three wolves meanwhile came to a junction of 2 logging roads. There they nosed around, scratched, and acted much as described above. Again the reddish wolf was most active and had its tail up.

"When the last 2 wolves came to this spot, they nosed around, ran back and forth, and 1 defecated. They then headed on a different branch of the trail than the first 3 had gone on just 10 minutes before.

"The first 3 wolves meanwhile were running along a logging road but eventually they circled and one other than the reddish one headed across a swamp toward the last 2. Then the reddish one and the other followed this one, and they met the last 2 on a ridge. There was the usual tail wagging, then all headed off together in a new direction. They passed the first scent post again and there was some nosing by the reddish wolf but little hesitation.

"When they traveled, one wolf lagged behind by 150 yards. The wolf just ahead of it had its tail vertical part of the time, as did the reddish leader.

"Soon the pack came upon another area packed with wolf tracks on a pond. There they followed every little trail, nose to the ground, wagged tails, grouped together often, chased each other, rolled over, etc. for 6 minutes. The reddish animal had tail up most of the time.

"The wolves continued on, and we left them about 1 mile S.W. of the S.W. arm of Bald Eagle Lake [at 6:05 p.m.]."

Unfortunately it was not known whether the trails that the wolves were following were their own or those made by other wolves.

Significant aspects of the above observation are (1) the spirited initiative of the leader, (2) the amount of time spent in scratching, urinating, and defecating, (3) the decision of the last two wolves to take a different route from that of the first three even though their goal seemed to be to catch up to the first three, and (4) the fact that the scent posts were located at trail junctions. In the last regard, we often noted from the ground that wolves urinated at the junction of newly formed human trails heading perpendicularly from roads they were following.

Copulation in wolves was only observed once during our study, on February 19, 1969. Two members of a group of four were seen coupled for 2 minutes on Kekekabic Lake. On Isle Royale, which is at the same latitude, copulations were witnessed on February 21, 24 and 27 (Mech 1966a).

On April 17, a den west of Big Moose Lake known to have been used at least intermittently for 13 years was seen from the air to have fresh activity of some kind in the snow in front of it, and on April 24 we saw a wolf at the mound. A few days later, two local human residents unaware of our interests approached this den and looked in. An adult wolf, presumably the bitch, leaped over their heads and fled the area. The men then dug up the den and removed six pups whose eyes had not yet opened.

Intraspecific Intolerance and Indifference

Instances of chasing or attack by a pack of wolves on conspecifics not a part of their group have been described by Murie (1944) and Mech (1966a). Observations of such behavior are important in trying to determine conclusively whether or not wolves are territorial. Pimlott _et al._ (1969, p. 75) wrote "It still is not clear, however, whether or not their use of range should be defined as territorial." Mech (1970) summarized the available evidence for territoriality in wolves and postulated that it may be spatiotemporal such that packs might avoid each other at any particular point in time but over a long period might cover the same area at different times. A number of our observations are pertinent to this question, for we have evidence of both, tolerance and intolerance between population units of wolves.

Two direct cases of intolerance were observed, both involving the radiotagged pack and other wolves within the usual range of the pack. Following is a direct quote from the field notes of Mech:

"Feb. 7, 1969--about 11:30 a.m.--aerial and visual--1059 and 2 other wolves traveling overland about halfway between Heart L. and August L. (R10W-T61 N. Sect. 17 center). They were traveling quickly and intently along a fresh wolf trail, with a lighter reddish individual in the lead. The other 2 animals were darker colored, and one of them was smaller than the other. One of them must have been 1059.

"We soon found that about half a mile ahead of the pack was a dark wolf hurrying away from the three. This animal often looked back and ran whenever it encountered good running conditions. It soon became obvious that the pack of 3 was chasing this individual. Because it [the lone wolf] often broke its own trail, the pack gradually gained on this animal. The single wolf flushed a deer which ran when the wolf was about 75 feet away and floundered in the snow, but the wolf continued hurrying on by.

"Although the deer ran only about 50 yards and stopped, the pack of 3 also hurried on by. The single wolf flushed another deer, ignored it, and continued by, as did the pack of 3. The chase continued for 2 miles as we watched, into the N.E. corner of Sect. 18 and then into the N. Central part of Sect. 8, and the pack got to within 150 yards of the single wolf.

"However, at this point, the 2 darker members of the pack had fallen about 100 yards behind the lead one. The lead animal stopped and waited for them, as it had done a few times before. It then turned around and headed back to these animals. When they met, the reddish animal's tail was held vertically and there was much tail wagging by all for about 1 minute. Then all animals lay down for a minute and then went up on a knoll. There was much activity and 'playing' on the knoll. (12:10 p.m.)

"The single wolf continued running and looking back for at least another mile. We left at 12:21 p.m.

"At 4:07 p.m. we saw a single wolf running across a small lake and looking behind it about 8 miles N.W. of these animals. The creature behaved the same as the one being chased today, and we wondered whether it could be the same animal."

On February 18, 1969, Ream made a similar observation, as follows (quoted from his field notes):

"Got visual sighting on 1059 with 3 other wolves at 11:55 about a mile west of Omaday Lake and they were running along fairly fast on a trail. When we circled a second time we saw 2 wolves curled up sleeping on a knoll ahead (south) of the running pack. We then realized the running wolves were on the trail of the sleeping wolves and when the pack of 4 with 'red' in the lead was about 50 yards from the knoll the 2 sleeping wolves jumped up and charged away in the opposite direction full tilt, and split and went in 2 directions. When the pack reached the knoll they started off on the trail of the wolf that headed N.E. and then changed and went after the one that headed S.W. The reddish wolf was in the lead and really picked up the pace. Although the reddish wolf seemed to gain on the chased one 3 or 4 times, the pack as a whole couldn't catch up, even though the single was breaking trail. The reddish wolf, after gaining, always stopped and waited for the others or went back to find them. They chased this wolf for 2-1/2 to 3 miles, all the way down to Highway 1 at a point 3.0 miles from the lab [Kawishiwi Field Station, U.S. Forest Service]. There was a dense patch, 10-15 acres, of woods just before Highway 1 and we lost sight of the chased wolf for a while and also the 4 when they entered it, but shortly we found that the chased one had somehow doubled back and was heading N.E. again. The pack was apparently confused for at one point 3 of them were wandering back and forth on Highway 1, apparently looking for the trail of the chased wolf. Two of these paralleled the Highway for a couple hundred yards and then stopped on top of a hill, apparently resting. During this chase both the single wolf and the pack chased up deer from their route of travel and didn't seem to pay much attention to them, even though some were really floundering in the deep snow. We finally stopped watching all of this at 1:30 p.m. and proceeded on our rounds."

On February 21 we also saw a single wolf running and looking behind several times on Ojibway Lake. Even when it saw a fisherman on the lake within 1/8 mile, it continued across to the opposite shore seeming most intent on avoiding whatever was on its trail. Presumably it had also been chased by a pack.

The cases of tolerance or indifference that we witnessed between wolves involved our lone animals. On January 27, 1051 was at a kill he had made the day before, and another wolf was sitting within 100 feet looking toward the carcass. Eventually the unidentified wolf left without approaching any closer. A lone wolf was also seen near 1053 in the general vicinity of a moose carcass, which probably both were feeding on at different times. Three such observations were made, on February 10, 15, and 18; and on February 21 another wolf was also seen near 1053 some 2.5 miles away from the moose carcass. In all cases, the two animals were 80 to 200 yards apart in open country and must have been aware of each other's presence.

Hunting, Killing, and Feeding Behavior

The primary prey of most wolves in our study area is the white-tailed deer (fig. 29), but some moose (fig. 30) are also killed. We have examined the remains of six moose that were eaten by wolves, two of which were killed by them (fig. 31). One was found on February 25, 1967, on Gillis Lake and the other on March 7, 1969, on Twinkle Lake. These locations are within 3 miles of each other, suggesting that a wolf pack in that area may be more accustomed to preying on moose than other packs. The other four moose carcasses were found in other parts of the study area, but circumstances were such that the causes of death of those animals could not be determined. A discussion of the details of wolf-moose relations in our study area must await the collection of additional data.

The remains of 93 wolf-killed deer, and 49 probable wolf-kills, were examined for age, sex, and condition and were compared with a sample of 433 hunter-killed deer from the same general area. The wolf-killed deer were generally much older than the hunter-kills and had a significantly higher percentage of jaw and limb abnormalities (see Mech and Frenzel, page 35).

Until recently the only observations of wolves hunting deer were those reported by Stenlund (1955) for northern Minnesota. He described two reports of actual observations and two reports of interpretations of tracks in the snow, all successful hunts. Since that time several descriptions of successful and unsuccessful hunts have also been published (Mech 1966b, Rutter and Pimlott 1968, Pimlott _et al._ 1969, Mech 1970). Nevertheless, many more observations must be made before generalizations can be formed.

During the present study we were able to witness a number of hunts from the air and piece together others based on tracks. The following descriptions are quoted from the field notes of Mech:

"26 January 1967. About 3/4 mile N.E. of Alice Lake.

"Jack Burgess [pilot] and I were following a pack of 8 wolves, when at 4:15 they veered from their former line of travel, about 30°. They were then about 200 yards from 2 deer. They began wagging their tails when about 175 yards from the deer. One deer, on the edge of a steep bank, was lying, but one was standing about 75 yards N. of it in open hardwoods. The wolves continued toward the latter deer.

"This deer remained standing in the same place until the wolves approached to within about 100 feet of it. The lead wolf stopped, when that distance from the deer, and the others caught up but also stopped when within about 25 feet behind the lead wolf. By this time the deer, whose body was facing away from the wolves, had its head turned back over its shoulder toward the wolves. The wolves and the deer remained absolutely still while staring at each other, 100 feet apart, for 1-2 minutes, while we made several circles.

"Suddenly the deer bolted, and instantly the wolves pursued. I am fairly certain that it was the deer that bolted first, but could be mistaken. The action was almost simultaneous. The deer headed toward the other deer near the top of the high bank. This animal had been lying but had arisen when the wolves were about 150 yards away.

"The lead wolf followed in the deer's trail, but the others cut toward the bank. This flushed the second deer (near the edge of the bank), which ran down the bank. Meanwhile when the first deer reached the edge of the bank, it headed due W. along the top of it. Only the lead wolf pursued this animal. The other deer had headed down the bank to the S.E., and at least a few of the wolves followed it.

"We could not watch both deer, so we continued following the first. The deer had no trouble in snowdrifts, but the wolf was hindered by them. The wolf followed the deer for about 200 yards along the top of the bank, and then gave up after losing ground. The wolf had run a total distance of about 250-275 yards. He then lay down and rested.

"We noticed at least 3 wolves stopped part way down the bank in the trail of the second deer. However, we did not see the remaining wolves or the second deer.

"Eventually (after about 5 minutes), these wolves joined the first, and all rested. At 4:25 p.m., one wolf started toward a third deer, which had been lying under a tree while the former chase took place. The deer was about 150 yards from where the wolves rested, and it had stood before the wolf started toward it. We could not see whether the deer or wolf bolted first, but suddenly both animals were bounding away. The wolf chased the deer about 125 yards and gave up after losing ground. The other wolves followed slowly in its trail, and all assembled and rested. The deer continued running for at least 1/4-mile."

"27 February 1969. 2 miles N. of August Lake.

"1059's pack of 5 was heading N.E. at 4:10 p.m. when they got to within 100 yards of 2 standing deer. The deer had been standing alertly in a shallow draw, and when at least 2 wolves got to within 100 yards, they fled. The wolves began running after them.

"The deer were in snow up to their bellies and had to hesitate slightly at each bound. But they ran fast. We could only see one wolf very much [of the time]. It was also having a difficult time in the snow, and after a total run of about 250 yards (100 to the deer's original location and 150 after the deer), the wolf lay on the snow and rested about 10 minutes. The deer ran only about 200 yards more and stood alertly for the next 20 minutes at least. The wolves then went on.

"27 March 1969. About 2 miles S.E. of Central Lakes, Minnesota.

"At 3:00 p.m. while we were following wolf 1051 by aircraft in above location, we saw a deer running very quickly on top of the crusted snow and then stand and watch its backtrail. About 1-1/2 minutes later we saw 1051 running along the same route. We did not see when the deer fled again, but saw it running about 100 yards from the wolf and doubling back paralleling its original route. When the wolf got near the approximate doubling-back point, he lay down and rested for about 5 minutes. The deer continued fleeing for about 350 yards, stopped, and for several minutes faced its backtrail. The wolf finally continued on in his original direction, giving up the chase.

"At 4:30 p.m.--1-1/2 miles S. of Central Lakes, Minnesota--Wolf 1051 had come to within 100 yards of [four-lane] Highway 53 and was hesitant to approach it. Several cars were going by in both directions. Thus the wolf headed S. parallel with the highway about 150 yards E. of it.