Feral populations of the canada goose Branta canadensis continue to grow at around 8% per year in the UK. The growing feral populations in Europe and non-migratory populations of ‘urban’ canada geese in North America are beginning to conflict with human interests. In response to increasingly frequent calls for control of this species, we review the scientific literature concerning the biology of feral populations in an attempt to determine why such rapid population growth has occurred. We also examine the available evidence about the problems caused by canada geese and the published information on the management techniques already tested. Feral canada geese are highly fecund, producing up to six young per pair, and have high fledging success. This allows populations to continue to grow even in areas with high levels of mortality in both adult and immature birds, mostly as a result of shooting. Population growth has been most rapid in urban areas with little shooting pressure and correspondingly low adult mortality. Site faithfulness, particularly in females, has probably slowed the spread of canada geese to new habitats, many of which have been created by man. Many apparently suitable sites remain unoccupied at present, and the factors which govern the carrying capacity of existing sites are not fully understood. The upper limits to the growth of feral populations are therefore difficult to estimate, but there is little evidence that density-dependent factors are acting to regulate population size except at long-established breeding sites. Canada geese can cause damage to agricultural crops and amenity areas resulting in significant localised economic loss particularly in areas close to water bodies. In most countries the extent and cost of the damage caused has not been fully evaluated, and evidence in support of the need for control on a national or international level is currently weak. Work on the impact of canada geese on other waterfowl and on the possibility that they may transmit diseases to humans is continuing. In Britain, research into management has concentrated on reproductive control by treatment of eggs. Results have shown that, even if the control is highly efficient, it takes a number of years for any reduction in the population size to occur. Most researchers suggest that reproductive control needs to be combined with an increase in adult mortality if the population size at a site is to be reduced in an acceptable time. We suggest that Integrated Management Strategies (combining habitat management, behavioural modification of the birds e.g. by scaring and, where necessary, by population reduction) need to be developed. These strategies should be specific to the particular location concerned. Current research in progress in the UK is summarised and areas where further research is needed both to quantify the problem and develop effective management strategies are identified.

A computer model was used to simulate processes of reproduction, growth and loss occurring during twelve months within a real-world brown hare Lepus europaeus L. population in a mixed farming area of central southern England. Model parameters representing hare density, and the density and diet of foxes Vulpes vulpes L., were derived from field studies, whereas likely values for other parameters were set on the basis of studies performed elsewhere. Simulations were created to represent a) the hare population on an area of 11 km² comprising several fox territories; and b) the hare population on individual fox territories. In the larger-scale simulations (a), the number of hares eaten by foxes easily exceeded their breeding density and amounted to 76–100% of annual production. The hare population could not have withstood more than a very low additional mortality without declining. When fox predation was set to zero, the final density of hares in the model was 3 to 6 times that produced when fox predation occurred. Simulations for individual fox territories (b) suggested that variation in territory size and social group composition of foxes introduced significant local variation within this overall picture. We conclude that the hares eaten by foxes were a substantial loss relative to productivity. This conclusion was robust in the face of estimation errors or changes in underlying assumptions of the model. This study describes the extent of fox predation on hares and its potential impact on hare population growth. Because the degree of compensation between mortality factors was unknown, the study does not show that fox predation per se limited the hare population. Nevertheless, our findings are a necessary adjunct to experimental evidence and population studies which suggest that red foxes play a major role in hare population dynamics in many environments.

Yearling natal dispersal frequencies and distances in roe deer Capreolus capreolus were compared between two regions in Scandinavia, Västerbotten, on the northern edge of the expanding population, and Mälardalen, in the central continuous part. Data were collected using telemetry during 1987–1994. In Västerbotten 91% (n = 11) of the males and 100% (n = 9) of the females left their natal areas, and in Mälardalen 43% (n = 42) of the males and 48% (n = 50) of the females dispersed. No intra-regional difference in distances dispersed was found between sexes. Average dispersal distance in Västerbotten was ca 120 km (n = 17), with only one disperser settling less than 39 km from its natal area. In Mälardalen, the average dispersal distance was around 4 km (n = 42), and only two animals moved further away than 15 km. One hypothesis accounting both for the almost complete dispersal of deer in Västerbotten, and for the existence of a few long-distance dispersers in Mälardalen, is that two genotypically distinct morphs of roe deer exist, one ‘dispersive’ and one ‘stationary’. The predominance of the ‘dispersive’ type in Västerbotten could be explained by ‘stationaries’ not having had enough time to colonise this region since the last population bottleneck in the mid 19th century, when the Scandinavian population was restricted to the southernmost part of Sweden.

The number of wolverines Gulo gulo in Scandinavia has declined dramatically since the middle of the last century, and the numbers killed continued to decrease until the species was protected. In 1968 the species was protected in Sweden; in 1973 the wolverine was given full protection in southern Norway and protection during the breeding period in northern Norway; and in 1982 the species was also given full protection in northern Norway. The protection has resulted in some increase in number, but the population density remains much lower than at the turn of the century, and the wolverine has yet not reoccupied all of its former range. Our analyses show that body size, as reflected by skull characters, was inversely correlated with population density from the mid-nineteenth to the mid-to late twentieth century. In contrast we found a strong decline in body size in the decades after ca 1960. The unexpectedly low wolverine resilience in this century may be explained by an energy-restricted model whose main factors include: 1) habitat fragmentation, 2) loss of habitat, 3) extinction of the dominant predator, the wolf Canis lupus, and 4) a maximised turnover in managed ungulate populations that has resulted in less natural mortality and fewer weakened animals available for scavengers and less efficient predators like the wolverine.

Regressions are presented to predict the total weight (TW) in kg of Scandinavian brown bears Ursus arctos from field-dressed weights (FW), where TW = 4.01 + 1.16 × FW, and slaughter weights (SW), where TW = 4.63 + 1.49 × SW. Both regressions had high predictive values (r² = 0.97) and were not significantly affected by sex or genetic lineage of the bears. Formulas to calculate confidence intervals are also presented.

Habitat use by different-aged broods and juveniles of teal Anas crecca, mallard A. platyrhynchos and goldeneye Bucephala clangula was investigated in southern Finland during 1988–1993. The study focused on within-lake habitat use and the use of flooded wetlands. Downy ducklings of all three species showed significant preference for Carex-stands. As the dabbling ducks grew older, their habitat use diversified, juveniles in particular also made considerable use of floating vegetation. Conversely, habitat use by goldeneye became more uniform: goldeneye juveniles were almost exclusively seen in open-water and floating vegetation habitats. All three species, but especially teal, used flooded areas intensively. Two thirds of teal downy broods were seen along flooded shores which comprised only seven percent of all shore habitats. Preliminary data suggested that the preferred habitat types, Carex and flooded shores, harboured more nektonic invertebrates and emerging insects than did the other shore types.