Håkan Sand, Henrik Andrén, Olof Liberg,
Per Ahlqvist, Grimsö Wildlife Research Station, Swedish
Univeristy of Agricultural Sciences, Sweden; Petter Wabakken,
Hedmark College, Department of Forestry and Wilderness Management,
N-2480 Koppang, Norway
The Scandinavian wolf population has undergone a strong (1,20)
recovery from a few individuals in the early 1980's to about
70 wolves in the winter of 1998/99. In december 1998 seven wolves
(3 adults and 4 pups) from three different packs were darted
from helicopter and equipped with radio collars. This was the
start of a long term study of population ecology of Scandinavian
wolves. All wolf pups (age=7 month) was of similar size and
weighed between 35 and 37 kg although their originated from
three different packs. Two adult females had a body weight of
34 and 38 kg while the adult male weighed 52 kg.
The radio collared wolves were located on average 3-4 times
per week using both telemetry from the ground and aerial tracking.
In addition intensive snow tracking from the ground were also
carried out where prey remains and wolf scats were collected
and analyzed.
Three alpha animals in two territories were studied and showed
an annual territory size of 750 km2 and 1000 km2 respectively.
During summer intensive radio tracking (24 hours a day) revealed
no distinct activity pattern. Wolves were only slighly more
active during early mornings and late evenings and moved on
average 25 km per 24 hours.
In March, at an age of 10 month, three of the four radio collared
juveniles dispersed from their natal territories while the last
radio collared juvenile dispersed in June. The young wolves
dispersed in different directions and at straight line distances
ranged from 13 km to more than 400 km. The true dispersal distances
recorded were generally more than twice the straight line distance
recorded.
Scat analyses and snow tracking of radio collared alpha wolves
showed that moose (Alces alces) was the main prey and
may constitute >90% of the biomass consumed in winter and
>85% in summer. Consumption of other prey species includes
roe deer (Capreolus capreolus), black grouse (Tetrao
tetrix) and hares (Lepus timidus).
In one of the studied territories the wolves killed moose
with an interval of 5-6 days during winter. The wolves were
successful in 71% of their hunting attempts on moose. Of the
29 winter killed moose 75% were calves, which indicates a strong
preference for this age class.
Winter density of moose and roe deer within the same territory
was estimated to 0,9 ± 0,12 and 0,06 ± 0,03 per 1
km2 respectively. A preliminary estimation of the impact of
wolves on the local moose populations, shows that wolves may
be responsible for taking 20-30% of the annual sustainable yield.
Harvest by humans is the main other cause of mortality in this
population of moose along with predation by brown bear.
Beyond 2000: