Petter Wabakken, Department of Forestry and Wilderness Management, Hedmark College, N-2480 Koppang, Norway; Håkan Sand, Olof Liberg, Grimsö Research Station, Swedish University of Agriculture Sciences, S-730 91 Ridderhyttan, Sweden; Anders Bjärvall, Swedish Environmental Protection Agency, S-106 48 Stockholm, Sweden

During 21 successive winters, 1978/79 - 1998/99, wolf population status, distribution and dynamics was monitored by snow tracking on the Scandinavian Peninsula (Sweden and Norway). The monitoring program involved cooperative Swedish-Norwegian fieldwork. Reports of sightings, tracks, and prey remains were also checked. On one-day censuses, hundreds to several thousands of volunteers participated in the search for wolf tracks. After the 1978 reproduction in the reindeer management area of northern Sweden, all new pairs and packs were located in the south-central parts of the peninsula, from 1983 and onwards. At the end of the study, in winter 1998/99, the population estimate was 62 - 78 wolves, about a 20-fold increase from the three wolves counted in 1982. During a 19-year period (1980/81-1998/99), the mean annual rate of population increase was 1.19 ± 0.02, while during 1990/91 to 1998/99 the annual population increase was 1.28 ± 0.04. During the study, 30-36 litters were raised. The mean pack size after the first litter raised by newly established pairs was 6.1 ± 1.4 wolves (n = 10) in early winter, but showed a decreasing trend during the 21-year study. Average pack size in winter for wolf pairs where and when breeding was confirmed more than once was 6.8 ± 1.9 wolves (n = 15) and showed an increasing trend over the study period. All but one of 33 reported wolf deaths were known to be human caused. Among dead wolves, adult males were on average 10.3 kg heavier than adult females. Females dominated among wolves killed within pack territories, while males dominated among wolves killed in areas outside such territories. Among wolves born in 1983 or later, 11 of 12 wolves killed outside the main wolf distribution area were males. Of 11 new wolf territories where breeding occurred, all except two were established without bordering other already existing territories. The average minimum new pair formation distance was 108 ± 76 km. To what extent this population is genetically isolated is at present unclear. The nearest, known neighboring wolf-breeding area is located about 800 km to the northeast, along the Finnish-Russian border. To ensure long-term survival of wolves in Scandinavia, we believe that immigration of wolves from the Finnish/Russian source population is needed. Cooperative Fennoscandian research on wolf genetics and population dynamics based on radio-telemetry is recommended. Cooperative Fennoscandian monitoring of wolves has been initiated.