Wolf movement is greatly hindered by deep, soft snow, so during winter
travel, wolves frequently use areas where they sink into the snow the
least. In our study area, frozen waterways are used extensively where
possible, just as reported by Stenlund (1955). Where few lakes or
rivers exist, wolves follow railroad beds and logging roads, often soon
after a plow or other vehicle has driven on them. In cutting cross
country through deep snow, wolves travel single file and tend to stick
to windblown ridges and to trails of deer and moose. Wolves that have
ranges small enough to cover in a few days form a network of their own
trails, which they can maintain merely by traveling regularly over
them. Packs on Isle Royale depended a great deal on such a system of
trails (Mech 1966a), and so did Pack No. 1059 in our study area.
Wolf packs can travel up to 45 miles in a day but it is usually larger
packs that do so (Stenlund 1955, Burkholder 1959, Mech 1966a, Pimlott
_et al._ 1969). In our study area we sometimes saw evidence of long
moves by large packs along strings of lakes and waterways. However,
most of our movement data pertain to lone wolves and a pack of five.
The daily travel of these animals was usually much less than that
reported for large packs.
Our radiotracking data provide an index to the extent of travel for
each wolf rather than the actual amount of travel, for it is based on
straight line distances between consecutive points at which an animal
was found. This measure will be referred to as the "net daily
distance."
Much variation was found in the net daily distances of wolves, with the
longest ranging from 4.5 miles for 1057 to 12.8 for 1055 (table 3). The
mean net daily distance for each animal, excluding days with no net
movement, varied from 1.5 to 3.6 miles. The movements of these wolves
may have been affected by the snow depth and penetrability, for mean
and maximum net daily distances suddenly increased for all animals
between February 23 and 28, when snow penetrability had decreased to a
point where walking wolves would be expected to sink in only about 6
inches (table 4). Other possible explanations for the wolves' sudden
increase in movements will be discussed below.
The straight line distances traveled between consecutive weekly
locations (called the "net weekly distances") showed a similar
variation (table 3). The maximum net weekly distance for each wolf
varied from 4.6 miles for 1059 to 49.0 for 1055, with means ranging
from 2.9 to 15.6 miles for the same wolves. No doubt 1059's net weekly
distances were relatively short because her total range and that of her
pack were much smaller than those of the other wolves.
It is difficult to obtain comparable measures of the extent of the
ranges covered by each of the radiotagged wolves because their patterns
of travel varied so much. Thus the figures given in table 5 should be
regarded only as gross indicators of the minimum range of each animal.
The area figures are especially deceiving in the case of 1055, for she
had a horseshoe-shaped range, much of which apparently was not used.
_Table 3.--Straight line distances (miles) between consecutive locations of
radiotagged wolves_
#: _Number_
%: _Percent_
---------------------------------------------------:----------------------------
: : Net weekly
: Net daily distances : distances
:----------------------------------------------:----------------------------
: : : : :Mean net : : : :
: : : : :distance : : : :
: Days :Days no : Days :Mean net:per day : :Weeks:Mean net:
Wolf: data : net :movement:distance:excluding :Range:data :distance: Range
# :obtained:movement: :per day :days of no: : :per week:
: : : : :movement : : : :
:--------:--------:--------:--------:----------:-----:-----:--------:-------
: # : # % : # % : Miles : Miles :Miles: # : Miles : Miles
1051 54 13 24 41 76 2.0 2.6 0.0-12.0 22 12.7 1.0-46.0
1053 37 20 54 17 46 1.0 2.1 0.0-5.0 23 6.3 0.0-23.6
1055 46 7 15 39 85 2.9 3.6 0.0-12.8 21 15.6 1.7-49.0
1057 29 11 38 18 62 1.0 1.5 0.0-4.5 15 4.6 0.0-31.0
1059 26 1 4 25 96 2.5 2.6 0.0-5.6 18 2.9 0.0-4.6
----:--------:--------:--------:--------:----------:-----:-----:--------:-------
Nevertheless, one major piece of information is obvious from the
figures: 1059's pack of five wolves had a much smaller range than any
of the other uninjured animals--approximately 43 square miles when
figured by the minimum-area method (Mohr 1947). The next smallest range
was that of 1051 (excluding the area of his later dispersal--see
below), which was some seven times the size of the pack's range.
_Table 4.--Straight line distances (miles) traveled between consecutive
days ("net daily distance") by radiotagged wolves in northeastern
Minnesota during February 1969_
+-------+-------------------------+-------------------------+
| | Mean net | Greatest net |
| Wolf | daily distance | daily distance |
|number +------------+------------+------------+------------+
| | Feb. 1-23 | Feb. 23-28 | Feb. 1-23 | Feb. 23-28 |
+-------+------------+------------+------------+------------+
| 1051 1.1 3.5 2.3 4.8 |
| 1053 0.7 2.5 3.0 5.0 |
| 1055 2.7 6.2 8.0 12.8 |
| 1057 1.0 1.5 4.0 4.5 |
| 1059 2.2 3.1 4.0 5.6 |
+-------+------------+------------+------------+------------+
There is little published information on the movements and ranges of
lone wolves with which to compare our data. Mech (1970) summarized
information regarding ranges of packs. Reported ranges varied from 36
square miles for a pack of two wolves in Minnesota (Stenlund 1955) to
5,000 square miles for a pack of 10 in Alaska (Burkholder 1959).
Considering only data based on intensive study in the same general
region (Minnesota, Isle Royale, and Ontario) as our study area, the
largest range reported was 210 square miles for a pack of 15 to 21
wolves on Isle Royale (Mech 1966, Jordan _et al._ 1967). On a per-wolf
basis, the ranges in this region varied from 6 to 28 square miles per
wolf. Our pack of five with its range of 43 square miles would have
about 9 square miles per wolf.
A more accurate assessment of the ranges of the radiotagged wolves
requires an individual discussion for each.
_No. 1051._--The range of 1051 was composed basically of three distinct
areas (fig. 19). Within 10 days after being released, the wolf left the
general area of his capture (Area A near Isabella Lake) and traveled to
Area B along Highway 1, some 17 miles to the southwest. From December 9
to January 4 wolf 1051 remained in Area B, which covers about 45 square
miles. Between January 4 and 6 he returned to Area A and stayed in 13
square miles until February 3. Between February 3 and 5 he shifted to
Area C east of Snowbank Lake, 11 miles northwest of Area A. He remained
in that 16-square-mile area until February 25, then suddenly left and
headed 8 miles to the northeast.
_Table 5.--Extent of ranges used by radiotagged wolves_
+--------+----------+----------+--------------+----------------------+
| Wolf | Greatest | Greatest | Total area[9]|Area[9] of intense use|
| number | length | width | | (before late Feb.) |
+--------+----------+----------+--------------+----------------------+
| _Miles_ _Miles_ _Sq. miles_ _Sq. miles_ |
| |
|1051[10] 28.5 13.6 318 13 (Location A[11])|
| 45 (Location B) |
| 16 (Location C) |
|1053 31.1 22.0 392 31 |
|1055 55.4 24.9 997 40 |
|1057 32.3 3.8 77 14 |
|1059[12] 8.4 8.0 43 39 |
+--------+----------+----------+--------------+----------------------+