The release of hand-reared ring-necked pheasants Phasianus colchicus in summer is a common practice in Britain to increase the number of birds available to hunters in winter. The breeding success of the birds which survive the shooting season is poor. Traditionally, birds are provided with supplementary wheat grain from release until the end of the shooting season (1 February) to maintain body condition and to help hold birds in areas for hunting. During 1997–2000 we assessed the effect of continuing supplementary feeding into spring on pheasant density and breeding success on seven private shooting estates. On each estate we randomly selected two distinct 1-km² plots and provided wheat grain via feed hoppers for birds in breeding territories in one of the plots on each estate while the other plot acted as an untreated control. Food was provided from mid-February to mid-May. We crossed-over the treatment and control plot on each estate each year. We conducted pre- and post-breeding pheasant counts in the plots during April and September. During April, densities were higher in treatment plots than in control plots for territorial males: (mean ± SE) treatment = 22.6 ± 1.5 birds/km², control = 14.8 ± 1.2 birds/km², (P < 0.001) and for females: treatment = 40.6 ± 5.8 birds/km², control = 24.1 ± 3.8 birds/km² (P < 0.001). In September we found no statistical effect of treatment on densities of adult birds or on brood size. However, more young were observed on treatment plots: 10.8 ± 1.5 birds/km², than in control plots: 5.6 ± 1.0 birds/km², (P = 0.02). In order to improve the breeding potential of released pheasants, we recommend that spring supplementary feeding is undertaken on shooting estates in Britain.

We tested the applicability of the bait-marking method in ravens Corvus corax to estimate their territory size during the breeding season in Białowieża Forest, eastern Poland. We marked 57 carrion baits and six additional carcasses with a distinctive type of plastic marker. The baits were experimentally placed around seven raven nests at different distances. A total of 1,018 pellets and 1,193 droppings from seven target raven nests, six neighbouring raven nests and from the communal roost were checked for markers. Ravens used 89% of baits and carcasses. In total, 705 markers, corresponding to 40 different baits and carcasses, were recovered. As confirmed by marker-type recoveries, ravens fed on 63% of experimental baits and 76% of those exposed inside the estimated territory. The proportion of baits utilised by a raven pair, as well as the total number of recovered markers declined with increasing distance of the bait from the nest. The probability of ravens feeding on a bait significantly decreased with greater distance from the nest. Distance from the nest correctly explained 84.5% of variation in the use of carrion by ravens. A threshold of 2,040 m indicated a raven territory size of 13.1 km². Raven pairs utilised baits and carrion further away than 2,040 m only exceptionally. Habitat characteristics and snow cover did not affect bait use and marker recoveries. Bait-marking was revealed as an efficient, accurate and economic method to estimate the territory size of scavenging birds, as well as to collect information on their movements.

Home ranges of mountain hares Lepus timidus were studied in boreal forests in Finland and compared to those on the British Isles and in Sweden. During 1998–2001 we radio-tracked 22 hares. Mean yearly home range size was 206 ha. Home ranges were largest in late winter-spring (mean: 202 ha) and smallest in autumn (mean: 71 ha). Home ranges were rather stationary, and only minor shifts in home range locations occurred between seasons. The hares used, however, partly different core areas in different seasons. Home ranges were much larger in the boreal forests of Finland, where the climate is cold, than in the moorlands and grasslands of the British Isles, where the climate is much milder. Home ranges in Finland were similar in size to those in the boreal forests of Sweden. In Finland and Sweden, winters are harsh, the growing season for plants short and the field layer vegetation is covered by snow from November until late April. The large home ranges in the boreal forests are probably mainly due to the low food availability in this environment.

Fish farmers were interviewed on the occupancy and impact of otters Lutra lutra at common carp Cyprinus carpio fisheries in southeastern Poland during a preliminary survey in 1994–1995 and in 2003. Otters occurred at 104 (91%) of 114 surveyed fisheries, and in 71 (62%) fish farms the perceived otter predation pressure increased over the last decade. Of the interviewees, 65 (57%) reported serious losses to otters, and of these 51 (78%) claimed to have no otters or to have had the otter problem under control in the mid-1990s. The most frequently listed type of damage was killing or serious injuring of the commercially most valuable brood fish and surplus killing of cultured carps. Nondestructive attempts to protect stocks from otters were reported only exceptionally. Of the farmers with depredation problems, 17% admitted that illegal otter killing occurred at their farms. Field surveys revealed that fish farmers correctly identified otter presence at their ponds. However, farms differing in the perceived otter impact on cultured stocks did not differ in their annual overall fish losses. Private pond owners perceived losses to otters as higher than managers of state-owned fisheries. Spraint analysis at two intensively monitored adjacent fish farms, one with perceived serious economic losses and one which reported a minor otter problem, showed similar proportion of carp by weight (44 vs 41%, respectively) in otter diet.

Along the Chobe Riverfront in northern Botswana, elephants Loxodonta africana have reduced woodland cover and modified woody species composition, forming shrublands. We tested the hypothesis that this has favoured the impala Aepyceros melampus population and contributed to the observed population increase by creating more available dry-season browse. Our results suggest that the increasing Capparis shrubland represents a key browsing habitat. The mixed Combretum shrubland was a less important browsing habitat, as female impalas browsed proportionally to the time spent feeding, but this habitat has more than doubled in extent, to almost 60% since 1962, thus providing much more available browse. The Baikiaea woodland, which has declined to less than half of its extent during 1962–1998 mainly due to elephant impacts, provided the least amount of dry-season browse for impalas. Impalas browsed mostly below 70 cm and conversion of woodland to shrubland has increased the availability of browse at this height. Our study suggests a three-way ecological interaction, with elephants changing the vegetation, and impalas increasing in number due to greater food availability.

In 1995, wolves Canis lupus were reintroduced into Yellowstone National Park, USA, where they began to prey on ungulate species. In response to this new predation risk by wolves, we predicted that the two main ungulate species, elk Cervus elaphus and bison Bison bison, should compensate by reducing their use of riskier open meadows and increasing their use of safer forest. Additionally we predicted that this shift in habitat use would result in reduced diet quality. We tested the first prediction by regressing the number of faecal groups in 10-m² sampling plots against distance from forest edges. To test the second prediction, we compared percent faecal nitrogen in elk and bison faeces between areas with and without wolves. We found a significant negative relationship between number of elk faecal groups and distance from forest edge in areas with wolves (r² = 0.65, P = 0.001), but we did not find a relationship between these two factors in areas without wolves. Mean percent faecal nitrogen in elk was significantly lower (F_(1,116) = 13.9, P < 0.001) in areas with wolves (1.7%, SE = 0.09, N = 40) than in wolf-free areas (2.1%, SE = 0.08, N = 80). For bison, we did not find any significant relationship between numbers of faeces and distance from forest edge nor in dietary nitrogen between wolf and wolf-free areas. We concluded that predation pressure from the reintroduced wolves was consistent with our prediction that elk shifted habitat use, thus lowering the quality of their diet. However, a similar change in use pattern and dietary quality of bison in response to wolf presence was not found.

Estimates of caribou Rangifer tarandus groenlandicus abundance in West Greenland in 2001 were much larger than estimates from the early 1990s. Two caribou populations, the Kangerlussuaq-Sisimiut of the North region and the Akia-Maniitsoq of the Central region, were examined for productivity. In total, 96 female caribou were collected in early and late winter from the subareas Kangerlussuaq and Akia, respectively. Data on reproductive status, reproductive history and animal age were collected. Maximum age observed was 15 years and mean age of death may be 12-13 years, which indicates a natural mortality of approximately 8%. Despite habitat differences in climate and vegetation, the two West Greenland caribou populations had similar pregnancy rates for mature females, i.e. ca 81% (P = 0.93). Likewise, mean fertility (total number of all pregnancies) for the age classes 1-10 years (age at breeding season) was not significantly different at 4.77 ± 2.38 and 4.23 ± 2.57, respectively (P = 0.65). Although West Greenland adult female pregnancy rates in 1996/97 were similar to those of North American caribou, the Greenland sample showed a high percentage of pregnant subadults. Further there was no significant difference between early and late winter pregnancy rates for either population. Fertility among Greenland females was excellent. Maximum potential number of pregnancies for their lifetime was attained by 25%, while 2-4% exceeded the maximum, and at the age of 10 Greenland females can be expected to have had > 7 calves. The high productivity in both populations may occur through first conception in the second autumn or twinning, both of which suggest summer forage of equal and excellent value for several years preceding this study. The potential for rapid growth in abundance of both populations was present in 1996/97 regardless of the dissimilar range characteristics.

In mouflon Ovis gmelini musimon × Ovis sp. populations, different morphological characteristics are often used to discriminate among age classes from observations in the field, such as horn size and horn development for males and size of white facial mask for females. In the Caroux-Espinouse mouflon population, we used linear discriminant analysis to test the ability of these two commonly used morphological characteristics to discriminate among age classes in the field. Models were developed using measurements taken from 643 mouflons harvested between 1977 and 1985. Classification ability of the horn length for males was poor (77.5%, SD = 15.0, N = 404) but better than facial mask length for females (40.1%, SD = 27.8, N = 212). Male lambs were the only age class successfully classified (≥ 90%). As reported elsewhere, we found that facial mask length was not a reliable predictor of male age (classification ability: 40.3%, SD = 21.7, N = 431). In the Caroux-Espinouse population, horn length and facial mask length were poor indicators of age. Our results suggest an important need to evaluate the reliability of criteria used in mouflon populations to discriminate among age classes from observations in the field. We recommend working with a restricted number of age classes and studying a combination of behavioural and physical characteristics.

Crop raiding by primates in particular and wild animals in general is a significant source of people-forest conflict around the Budongo Forest Reserve, Uganda. Crop loss to wild animals undermines local support for conservation efforts in this area. Patterns of primate crop raiding were studied over a period of 14 months in six villages (five adjacent to the Budongo Forest Reserve and one that is approximately 3,500 m from the forest edge). Data were collected via a questionnaire survey. Additional information was obtained from the relevant local government offices. Chimpanzees Pan troglodytes, baboons Papio anubis, other monkeys, bush pigs Potamochoeus procus and porcupines Hystrix cristata were reported by farmers to be the major causes of crop losses by wildlife. Of farmers, 73% reported suffering crop damage caused by primates, and 79% considered baboons to be the most destructive of all crop raiding species. Drought, insect pests, poor sowing, plant diseases and accidental fires were other sources of crop losses to farmers, though the risk of crop damage particularly by primates is perceived as the most serious potential cause of losses. Using chimpanzees as a case study, patterns of crop damage across the year are compared with seasonal fluctuations in availability of wild foods.

Restocking is a widespread management practice used to support wild populations of European rabbit Oryctolagus cuniculus which are jeopardised by habitat loss and disease outbreaks. However, rabbits are known to experience a high mortality just after release, which might be due to the handling stress induced by translocation, and particularly to storage condition between capture and release. In our study, we tested two soft treatments of storage in boxes, where rabbits were stored either alone or in groups of four or five, and we assessed both survival rates and maximum dispersal distances by radio-tracking 43 individuals during eight weeks after release. We also recorded data about the survival at the time of release for 11 other rabbits that either died before release or were not radio-equipped. Our study involved two similar experimental releases in 2001 and 2002 in distinct nearby study areas to assess the effect of storage condition. Rabbits were released in two subsequent batches at a few days interval. Overall cumulated survival over the first 10 days after capture was 61%, and 96% during the subsequent 46 days. There was no clear overall effect of the storage method used on early survival: all individuals stored in groups survived in the second experiment, but not in the first experiment, whereas early mortality was equal for individually stored rabbits in both experiments. Otherwise, there was no effect of sex and batch on survival. Maximum dispersal distances from the release sites ranged within 20–280 m, except for two rabbits that moved 1.1–1.4 km away. Dispersal after release depended on both experiment and batch, but neither on sex nor on storage condition. It is not possible to conclude from our results that storage condition is a critical factor determining release success in wild rabbit, at least not the soft treatments that we tested.

I carried out a 2-year study on otter Lutra lutra dietary composition at a fish farm in southeastern Poland, where otters were perceived to inflict serious damage to common carp Cyprinus carpio stocks. The aim of my study was to determine the role of commercial fish in the diet of otters living in habitats comprising carp fisheries. Otter diet was examined by scat analysis. On an annual basis, carp dominated otter diet with 43% by weight. However, in terms of numbers, smaller wild species such as Prussian carp Carassius auratus gibelio (27%) and roach Rutilus rutilus (12%) were more abundant in the diet, whereas carp accounted for only 10%. The availability of farm cohorts of different age compared with frequencies of carp age classes recorded in spraints indicated otter preference of 1 over 2 carp. The exploitation of farmed stocks was most intense from autumn to early spring, unless the access to stocks was prevented by the presence of ice cover. In areas with carp farms, otters may rely on cultured stocks, especially during periods of food stress.

In order to develop more practical indices of fat contents in fisher Martes pennanti populations at a large scale, the relationship between individual discernable fat depots (popliteal, sternal, omental, mesenteric and perirenal) and fat percentage (PFAT) was examined in male and female skinned carcasses obtained from trappers in northeastern Ontario from the 1998/99 and 1999/2000 fur harvest seasons. PFAT differed significantly between sex/age classes (F = 10.17, P < 0.0001). In a development group (86 males and 86 females), PFAT was well predicted by each of the five potential fat indices common to both males and females. During the test phase (87 males, 93 females), estimated fat contents (%) based on either fat depot did not differ from observed PFAT neither in males nor in females (0.05 < paired t < 1.33, 0.19 < P < 0.71). All models detected animals with lower fat levels, a useful feature for conservation applications. The accuracy of almost any of the five depots appears adequate to detect changes in fat levels in harvested fisher populations. This contrasts with other mustelids such as martens Martes americana where lower fat levels restrict the availability of discernable fat depots.