We collected carcasses of 52 common eider Somateria mollissima adults and ducklings and blood samples from 11 nesting eider hens in the Gulf of Finland near Helsinki in 1994, 1995 and 1996. Samples of liver tissue were analysed for arsenic, cadmium, chromium, copper, iron, lead, magnesium, manganese, mercury, molybdenum, selenium and zinc. Blood was analysed for lead, mercury and selenium. Most of the 21 adults examined at necropsy were emaciated with empty gizzards, and no ingested shotgun pellets or other metal were found in any of the birds. Three adult females had a combination of lesions and tissue lead residues characteristic of lead poisoning. Two of these birds had acid-fast intranuclear inclusion bodies in renal epithelial cells and high concentrations of lead (73.4 and 73.3 ppm; all liver residues reported on dry weight basis) in their livers. The third was emaciated with a liver lead concentration of 47.9 ppm. An adult male had a liver lead concentration of 81.7 ppm, which is consistent with severe clinical poisoning. Two other adults, one male and one female, had liver lead concentrations of 14.2 and 8.03 ppm, respectively. Lead concentrations in the blood of hens ranged from 0.11 to 0.63 ppm wet weight. Selenium residues of ≥60 ppm were found in the livers of five adult males. Selenium concentrations in the blood of hens ranged from 1.18 to 3.39 ppm wet weight. Arsenic concentrations of 27.5–38.5 ppm were detected in the livers of four adult females. Detectable concentrations of selenium, mercury and molybdenum were found more frequently in the livers of adult males arriving on the breeding grounds than in incubating females, while the reverse was true for arsenic, lead and chromium. Mean concentrations of selenium, copper and molybdenum were higher in the livers of arriving males than in the livers of incubating hens, but hens had greater concentrations of iron and magnesium. Concentrations of trace elements were lower in the livers of ducklings than in the livers of adults.

From 1991 to 1995, we tested the effects of radio-tracking, including trapping, handling and monitoring, on reproductive success of black grouse Tetrao tetrix hens in the southern French Alps. Reproductive success (total young/total hens with and without broods) was lower in hens marked with radio-collars than in unmarked hens (0.77 vs 1.66 young/hen, P = 0.02). Brood size was similar in the two groups of hens, but the proportion of hens rearing a brood was lower among marked hens (23 vs 45%, P = 0.03). Reproductive success of hens marked at the beginning of laying, or just before, was lower than that of hens marked ≥6 months before laying (0.25 vs 1.20 young/hen, P = 0.058). The success of hens marked near the time of laying was also low compared with unmarked hens in all years but 1992 (the year*time of capture interaction was significant). In contrast, reproductive success of hens marked ≥6 months before laying was not statistically different from that of unmarked hens (1.20 vs 1.66 young/hen, P = 0.28). Higher predation rates on first clutches, and to a lesser extent lower ability to renest, were responsible for the lower reproductive success of hens marked at the beginning of or just before laying. Altogether, these results suggest that initial discomfort caused by the transmitter, stress of capture, handling and monitoring following capture may temporarily alter the behaviour of hens, thereby increasing detection of their nests by predators. After a period of adjustment, radio-transmitters per se may have little or no adverse effect on reproduction. We conclude that to obtain reliable estimates of breeding parameters of black grouse in the French Alps using necklace type transmitters, hens must be equipped with these several months before laying, and nesting hens should not be approached closer than 20 m during radio-tracking.

In studies of population dynamics and harvesting, differences in the demographic parameters of males and females are rarely dealt with explicitly. However, polygyny and sexual dimorphism, commonly observed in game animals, often result in sex differences in demographic parameters. A structurally simple deterministic two-sex model was used to study the equilibrium population size and adult sex-ratio under constant-quota harvesting. The model allowed varying harem and brood size, condition dependent sex allocation and sex differences in recruitment probability and adult survival. The results show that demographic sex differences may lead to a recommendation for female biased culling. Adult sex-ratio optimal for population growth is not evolutionarily stable. However, constant-quota harvesting can lead to the optimal adult sex-ratio for population growth in situations in which the mating system and female reproductive strategies would result in a radically different adult sex-ratio if the population were left unharvested.

Walrus Odobenus rosmarus hunting was conducted for hundreds of years in large parts of the European Arctic. Catch statistics are incomplete, or non-existent, and it is therefore difficult to determine the original population numbers for the different geographical areas. One exception is the Russian archipelago Franz Josef Land. These islands were discovered in 1873, and large-scale walrus hunting started there in the late 1890s and continued for four decades. It is therefore possible to estimate the minimum original population size based on catch statistics from Franz Josef Land for the last century. Using a simple population model backcalculation of the Franz Josef Land population to 1897 produces an estimate of 6,000–12,500 walruses.

Two hypotheses regarding roe deer spacing in low-density areas during the breeding season are: 1) that male territory size is equal to that of the female home range size or 2) that male territory size is larger than the female home range. I tested the two hypotheses using data on the home range sizes of nine female, and the territory sizes of 12 male roe deer radio-tracked during the summers of 1994–1996 in the Lier valley, southern Norway. There was no support for hypothesis 1, as male territory size was 1.5–1.9 times larger than female home ranges after correcting for altitude. Contradictory results in the literature regarding the effect of density on male roe deer territory size suggest that density alone does not satisfactorily predict roe deer spacing. I present the female dispersion hypothesis which presumes that as the area occupied by females decreases (due to high resource levels), the cost-effectiveness of male territoriality increases. Thus, the territory size of roe deer males, relative to female home range size, is expected to be largest when females are divided into local spatial units and female home range is relatively small. Comparative observations in two low-density populations seem to support this hypothesis.

Mortality and survival of white-tailed deer Odocoileus virginianus fawns (N = 29) were studied from birth to one year of age during 1991–95 on Mount Desert Island (MDI), Maine, where deer hunting is prohibited, coyotes Canis latrans have become recently established, and protected U.S. National Park lands are interspersed with private property. The rate of predator-caused mortality was 0.52, with coyote predation (N = 8) accounting for at least 47% of mortalities from all causes (N = 17). Mortality rate from drowning was 0.24 (N = 3), and from vehicles 0.14 (N = 3). For fawns radio-collared as neonates, 10 of 14 mortalities occurred during the first two months of life. Annual rate of fawn survival was 0.26. Survival rate from six months to one year was 0.65 and four mortalities (two predation, two drowning) were observed during this interval. A subgroup of fawns (N = 11) captured near a residential area and along the periphery of a coyote territory had a higher rate of survival to one year of age (S = 0.67) than did fawns from all other areas (N = 18, S = 0.00). Recruitment to one year of age was lower than that observed in other deer populations in the northeastern United States. Low recruitment associated with coyote predation and mortality sources associated with humans appears to be limiting white-tailed deer populations in some segments of this insular landscape.