Yields in pound nets are in particular damaged or reduced by cormorant Phalacrocorax carbo predation. In this study we examined the effect on predation in pound nets by mounting barrel nets vertically under the water in the pot in order to obstruct cormorants during their hunt. To keep control of the content of fish we used an experimental pot with a closed throat. The pot was stocked repeatedly with rainbow trout Oncorhyncus mykiss and its content of fish was thereby maintained at between 10 and 100 individuals during all periods of data collection. Video recordings, both above and under water, were carried out during May - August 1995 under various experimental conditions. We tested five different barrel net arrangements including a control situation without barrel net. Two bird categories were defined a posteriori: those that caught one or more fish during their visit to the pot (successful birds) and those that failed to catch a fish (unsuccessful birds). Successful and unsuccessful birds differed in a number of ways. Successful cormorants stayed longer in the pot, performed more dives, and spent more time diving and shorter time on the surface. When barrel nets were present, fewer cormorants of both categories visited the pot. Furthermore, the barrel nets affected successful birds by increasing the number of dives required to catch their first fish, reduced the time that both successful and unsuccessful birds remained in the pot, and reduced the number of dives performed by unsuccessful birds. Therefore, it seems that barrel nets may have a potential as a predation reducing device in pound net fishery. Introducing the use of barrel nets in pound net fisheries may force cormorants to hunt in free waters, possibly with reduced foraging success. This may eventually lead to a reduction in the cormorant population which will make it better fit the natural carrying capacity of the environment.

To evaluate the usefulness of restocking of grey partridge Perdix perdix in marginal ranges we studied survival, spring dispersal and breeding success of wild and released grey partridge females using radio-tracking. Released females had lower survival during the breeding period than wild females. Within the limitation of the small sample size obtained from the released birds surviving till nesting, there was no difference in spring dispersal, nesting chronology, clutch size, and nest predation between wild and released birds. However, wild partridges produced more fledglings per radio-tracked female than released birds. This difference was mainly due to the higher survival rates of wild hens compared to those of released hens before the incubation period. We conclude that due to their poor survival and reproduction output, released birds may have little value in attempts to boost threatened wild populations of the grey partridge, whereas habitat management and predator control could be more useful tools for the preservation of grey partridge populations in marginal regions.

The seasonal food habits of brown bears Ursus arctos were estimated based on the analysis of 266 scats in central Norway and Sweden. Free-ranging domestic sheep Ovis aries were common in the Norwegian part of the study area, but were not found in the Swedish part. Correction factors were used to correct for differences in digestibility and nutritional value of different foods. Because correction factors for ungulates are difficult to estimate, the results should be interpreted with some caution. In terms of digestible energy, ungulates, mostly carrion, were the most important food in both areas during spring. During summer, ants, forbs, and ungulates (reindeer Rangifer tarandus and moose Alces alces) were the most important food items in the Swedish area, and sheep were most important in the Norwegian area. The autumn diet was dominated by berries in the Swedish area and sheep and berries in the Norwegian area. Among berries, crowberry Empetrum nigrum was the most important species, followed by bilberry Vaccinium myrtiUus in Sweden. The major difference between the Swedish and Norwegian areas was the large consumption of sheep in Norway, which provided protein and lipids, and was associated with a relatively reduced consumption of ants and forbs in summer and berries in the autumn. Based on different ingestion rates among the seasons, we estimated the relative contribution of major foods to total digestible energy. In the Swedish area, bears obtained 44–46 and 14–30% of their total annual energy from berries and ungulates, respectively. The remaining energy was obtained from insects (14–22%, mostly ants) and forbs and graminoids (12–18%, mostly blue sow thistle Cicerbita alpina). In Norway, bears obtained 65–87% of the energy from ungulates (mostly sheep), 6–17% from berries, 5–13% from insects, and 2–6% from forbs and graminoids. To gain weight prior to denning, brown bears in Norway selected lipid-rich and easily obtainable sheep in summer and autumn. In Sweden, they relied on carbohydrate-rich berries in autumn.

Minimum numbers of wolverines Gulo gulo were estimated for Scandinavia, based on the average number of active dens recorded in 1995–1997. To estimate the proportion of females active at dens, we followed individual females using radio-telemetry in northern Sweden, northern Norway and south-central Norway. The sex and age structure of the population was estimated based on a sample of wolverines harvested before the introduction of protective measures and harvest restrictions. Our results are compared with those found in other published wolverine studies, mostly from North America. The Scandinavian population of one-year-old and older wolverines was estimated at 413 ± 71 (SD) individuals (265 ± 55 in Sweden and 147 ± 25 in Norway). This method gave a lower population estimate than those found in earlier surveys based on summation of local (municipality) estimates (Troms) and on local tracking surveys (Nordland). The differences may be explained by the existence of a large number of undiscovered natal dens in the two counties mentioned above, but the previous estimates were based on methodologies with sources of error that could inflate estimates. The population size in south-central Norway (the Snøhetta plateau, Trollheimen, Reinheimen and Rondane), based on the average number of active natal dens during 1995–1997, was estimated to be 26 ± 7 individuals. This was in concordance with the 23–30 individuals estimated from intensive tracking and radio-telemetry in spring 1995. Monitoring wolverine reproduction as a basis for population estimates could provide an important management tool. Based on our results, we recommend that the management authorities in Norway closely monitor the presently high harvest rate of wolverines in parts of the country, and establish population monitoring methods that allow continuous evaluation of management strategies.

Lynx Lynx lynx hunting in Norway is regulated through regional quotas according to the magnitude of predation on semi-domesticated reindeer Rangifer tarandus and domestic sheep Oves aries. Lynxes and semi-domesticated reindeer were studied using telemetry in an area in Nord-Trøndelag County, Norway, with high lynx predation on reindeer and domestic sheep and a high hunting pressure on lynxes. The probability of an ungulate killed by lynxes being livestock as opposed to a roe deer (the only alternative wild ungulate) increased with increasing distance from fields (P < 0.0001) and roads (P < 0.0001). Hunting was the only mortality cause found for radiocollared lynxes. The culling of lynxes was biased towards the vicinity of roads and cultivated fields compared with the general distribution of radiocollared lynxes (P < 0.001) and radio-collared semi-domesticated reindeer killed by lynxes (P < 0.001). Because of the easy location in rural areas due to the well-developed road system, lynxes suffered the highest hunting mortality in habitats where the proportion of livestock in the diet was lowest, whereas lynxes inhabiting alpine areas more than 3 km from the nearest road escaped hunting. The hunters' preference for hunting lynxes near roads leads to a risk of selective reduction in regions and habitats where lynxes do little harm, whereas numbers in remote areas with high predation on livestock may remain unaltered.

The tolerance of lynxes Lynx lynx to human presence and disturbance in a hunted population in Norway was studied using telemetry. Forest land within 200 metres from the nearest road or house was avoided by lynxes when resting (P < 0.01). The tolerance distance of resting lynxes towards intruding people was short (median 50 m), though strongly correlated with the horizontal vegetation cover (partial correlation, P < 0.02) and forest maturation stage (partial correlation, P < 0.02), but not with terrain inclination (partial correlation, P > 0.3). The lynxes did not enter steeper country (P > 0.4) or alter their daily walking distance (P > 0.7) after being disturbed. The data indicate that lynxes, even when suffering extensive, man-induced mortality, may tolerate high human activity within their range as long as sufficient stands of undisturbed, mature forest with dense horizontal cover are present.

Male fallow deer Dama dama exhibit inter and intrapopulation variation in mating behaviour, including both territorial and non-territorial mating tactics. During 1993 I investigated the relationship between fallow deer mating territory location and female distribution in relation to habitat characteristics at the Ottenby nature reserve in southern Sweden where males defend isolated mating stands during the autumn rut. Mating stands were positively associated with dense canopy cover and the presence of hazel Corylus avellana trees, but negatively associated with the number of alder Alnus glutinosa trees. Preference for such sites may be connected with the types of display males engage in during the rut as both auditory and olfactory means of communication can be affected by habitat structure. In relation to one another, the stands were randomly dispersed throughout the wooded region and along the perimeter of fields, with no indication of clumping or overdispersion. Female distribution was not associated with any of the habitat characteristics, or with stand location. The idea that males might be defending areas of favoured resources was ruled out as a possible explanation for stand location, although the idea that males might be defending game trails frequented by females remains as a potential determinant of stand locations.