Ecological Studies of the Timber Wolf in Northeastern Minnesota Part 3

[Ill.u.s.tration: _Figure 21.--Locations and range of wolf 1053. Only selected lakes are shown._]

Between February 28 and March 6 she suddenly moved 13 miles to the east-southeast near the Sawbill Trail, and during the next week she traveled a straight line distance of 24 miles southwest to a point southeast of the town of Isabella. Her subsequent travels eventually took her over a much larger area. Before February 28, 1053's average weekly straight line distance was 2 miles, but after that date it increased to 11 miles.

_Wolf 1055._--The range of this animal from January 5, when she was captured, to February 23 covered about 40 square miles near Stony Lake, Slate Lake, and the Jack Pine Lookout Tower (fig. 22), and her mean weekly distance was 4 miles. Between February 23 and 24, however, she traveled 13 miles northeastward, the beginning of a series of long moves. By March 5, 1055 had reached Crescent Lake, a point 39 miles east-northeast of her previous area of intensive use. She then gradually headed back toward the west and south during the next 10 days and within the next month repeated this pattern. When her signal was heard last on May 30, 1055 was near Martin Landing in the center of her range. Her mean net weekly distance after February 23 had increased to 22 miles.

[Ill.u.s.tration: _Figure 22.--Locations and range of wolf 1055. Only selected lakes are shown._]

_Wolf 1057._--The movements of 1057 cannot be considered normal because freezing of a front foot prevented her accompanying the pack of which she was a member. Nevertheless, even data from an abnormal animal can provide some information. On January 13, 5 days after capture and release on Red Rock Lake, 1057 was located 4 miles from the capture point with a pack of 10 other wolves. She was limping and fell behind when they moved. Five days later she was again seen with the pack 12 miles away between Knife Lake and Kekekabic Lake. She then remained in about 14 square miles of that general area through April 17 (fig. 23).

[Ill.u.s.tration: _Figure 23.--Locations and range of wolf 1057. Only selected lakes are shown._]

Suddenly on April 24, 1057 was found in Ontario some 31 miles northeast of her location of the previous week. That was the last time we heard her signal even though on May 2 we scanned an area with a radius of 35 miles from her last known location and listened for her signal during every subsequent flight.

_Wolf 1059._--This animal was a member of a pack of three to five wolves (see next section). The movements of the group varied little and were concentrated in the August Lake, Omaday Lake, and Keeley Creek area in about 43 square miles (fig. 24). Contrary to animals 1051, 1053, and 1055, this pack did not suddenly begin a series of longer weekly movements in late February. Both before and after February 28, the average weekly straight line movement of the pack was just less than 3 miles.

[Ill.u.s.tration: _Figure 24.--Location and range of wolf 1059 and pack.

Only selected lakes are shown._]

Probably these animals did begin traveling more in late February, for their net daily distances did increase at that time along with those of the other wolves (table 4). However, the increased travel took place within the restricted area of the pack's usual range rather than in new areas as occurred with the other wolves.

Because 1059 was later found to have bred and carried five fetuses, her movements during whelping season (late April and early May) are of interest. Her locations on both April 24 and May 2 were within 250 yards of each other, which might indicate that she was denning. On May 9, however, she was 2.5 miles east of these locations, on the 17th and 21st was 2 miles west of them, and on the 30th was 3 miles north of them.

In early January 1970, Wolf 1059 was killed by a trapper in the southeast corner of her pack's 1969 range.

_Summer locations._--Signals from only 1053 and 1059 were heard during summer, and then tracking attempts were made only on June 28, July 29, and August 29. Locations for 1053 on those occasions were near Kelly Landing and Isabella Lake, within her previous range. Wolf 1059 was found each time within 2 miles outside of the southwest corner of the pack's winter and spring range.

Wolf a.s.sociations, Social Behavior, and Reproduction

In our study area, population units of wolves exist as both single animals (lone wolves) and packs. In a total of 77 observations, lone wolves const.i.tuted 32 percent of the sightings (fig. 25), with packs of from 2 to 13 members making up the remainder (Table 1). On the basis of the number of wolves seen, rather than the number of observations, lone wolves accounted for only 25 (8 percent) out of 323.

[Ill.u.s.tration: _Figure 25.--Only 8 percent of the wolves observed were lone wolves. (Photo courtesy of L. D. Frenzel.)_]

These figures compare favorably with reports in the literature as summarized by Mech (1970). In five areas studied, lone wolves made up from 24 to 60 percent of the observations of population units, and from 8 to 28 percent of the wolves seen. In our study area during 1948 to 1953, lone wolves const.i.tuted 43 percent of the observations and 15 percent of the wolves (Stenlund 1955).

The average size of the population units observed during our study (total number of wolves seen divided by the number of observations) was 4.2, which is significantly larger (95 percent level) than the average seen in this area (2.8) from 1948 to 1953. This is also larger than that reported from any other area of comparable size (table 6).

_Table 6.--Mean sizes of wolf population units reported from various areas_

---------+------------+--------+------------+---------+--------------- Mean size of Largest Authority Area Observations Wolves population pack size calculated from unit ---------+------------+--------+------------+---------+--------------- _Number_ _Number_

Alaska 310 1,041 3.4 12 Kelly 1954 Alaska 1,268 4,823 3.8 21 R. A. Rausch[13]

Lapland 118 311 2.5 12 Pulliainen 1965 E. Finland 460 984 2.1 12 Pulliainen 1965 Minnesota 112 318 2.8 12 Stenlund 1955 Minnesota 77 323 4.2 13 Present study ----------------------------------------------------------------------

FOOTNOTES:

[13] R. A. Rausch. Personal correspondence to L. D. Mech, 1967.

The largest pack seen in our study area included 13 members, and there apparently were at least two such packs. Although larger packs than this have been reported, any group containing more than 8 to 10 members is unusually large (Mech 1970).

Wolf sociology is a complex subject and is still not well understood, so the following detailed observations of the a.s.sociations between our radiotagged wolves and others are given. a.s.sociations are defined as relationships in which two or more wolves relate in a close, positive manner.

As mentioned earlier, 1051 may or may not have been a.s.sociated with other wolves when he was captured. However, although this animal was observed 55 times throughout winter and spring, only twice was he seen a.s.sociating with another wolf. Probably the same individual was involved each time, because the location was about the same (the vicinity of the juncture of Aitkin, Carlton, and St. Louis Counties).

The first occasion was on April 3. Wolf 1051 in the previous week had moved 46 miles straight line distance from the northeast. He was then observed lying peacefully within 15 feet of another wolf near a freshly killed deer. The very proximity of the two animals implied a positive relationship. On April 7, 10 and 14, 1051 was seen 1 mile, 10 miles, and 8 miles from the kill and was alone each time.

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 a.s.sociated 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 a.s.sociate 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 a.s.sociate 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_ _a.s.sociations_

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.

[Ill.u.s.tration: _Figure 26.--One of the radiotagged wolves was a member of this pack of five. (Photo courtesy of L. D. Mech.)_]

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:

[Ill.u.s.tration: _Figure 27.--Feces, urine, and scratching in a conspicuous spot indicate a wolf "scent post." (Photo courtesy of L. D. Mech.)_]

"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.

[Ill.u.s.tration: _Figure 28.--A pack of wolves investigating a scent post. The raised tails indicate their excitement. (Photo courtesy of L. D. Mech.)_]