Estimating population size and trends are key issues in the conservation and management of large carnivores. The rebounding brown bear Ursus arctos population in Sweden is monitored by two different systems, both relying on voluntary resources. Population estimates have been calculated using Capture-Mark-Recapture methods, based on DNA-based scat surveys in five of the six Swedish counties with established bear populations. A total of 1,358 genotypes were identified using DNA extracted from collected scats. An independent ongoing programme, the Large Carnivore Observation Index (LCOI), was initiated in 1998. The LCOI uses effort-corrected observations of bears by moose Alces alces hunters during the moose hunt (> 2 million observation hours/year) and has shown a good correlation with relative population density of bears using the DNA-based method. From this, we have calculated population trends during the period 1998-2007. Using an exponential model, we estimated the yearly increase in the bear population to be 4.5% at the national level, varying between 0 and 10.2% in different counties. We used the regional population estimates and the trends from the LCOI, taking the variation from both systems into account using parametric bootstrapping, to calculate the regional as well as the national population size in Sweden in fall 2008. In one case (the northernmost county; Norrbotten) a DNA-scat survey was lacking, so we used assumptions based on data from the neighbouring county to estimate population size. We estimated the Swedish brown bear population to be 3,298 individuals (2,968-3,667; 95% confidence intervals) in 2008. Our results suggest that reliable information, necessary for the management of the brown bear population can be obtained from volunteers using standardised methods.

Common eiders Somateria mollissima nest in colonies on islands of the St. Lawrence Estuary in Quebec, Canada. After hatching, attending females must reach suitable brood-rearing habitats while non-attending females and adult males must find appropriate moulting sites. The aim of our study was to determine the biotic and abiotic factors that influence the distribution of common eiders during the brood-rearing and moulting periods. We conducted biweekly surveys and recorded the number of ducks by age and sex in 2003 and 2004 at 68 sites along a 200-km stretch of the south shore of the St. Lawrence River. We further classified adult females according to the presence or absence of young. We evaluated human disturbance during the surveys and developed a sinuosity index describing shoreline protection. We determined the nature of the substrate and an estimate of food abundance for a subsample of sites (N = 38). At the scale of the estuary, common eiders did not distribute randomly but used the same sites in both years. Broods preferred mainland sites near nesting islands. Non-maternal females and males were located further east along the estuary, but their numbers were lower than expected based on the size of the breeding population, indicating that some birds undertake a moult migration outside of the area. In the eastern portion of our study area, densities of non-maternal females increased significantly as summer progressed. The distribution of common eiders was influenced by food abundance and type but was not related to our indices of human disturbance and shoreline protection. Males were associated with mussels, non-maternal females with both mussels and gammarids, while maternal females with ducklings were associated with periwinkles. Few of the sites used by common eiders along the south shore of the St. Lawrence Estuary are currently protected and measures should thus be taken to insure their conservation.

We surveyed red grouse Lagopus lagopus scoticus using pointing dogs in spring and again in summer from 2000 to 2010 on four moors in northern England using a line-transect distance sampling method. We compared density estimates generated with those obtained using three other methods on the same moors: counts of calling males within sample blocks of 0.5-km², absolute counts of grouse within sample blocks of 0.5-km² using a line of beaters and gamekeepers' own transect counts obtained using their dogs. We found that distance estimates were positively correlated with abundance estimates from all three sampling methods. Our distance sampling estimates of males pre-breeding were 47% higher than call count estimates, with pre-breeding distance sampling estimates 65% higher than the absolute counts. Distance sampling along transects across the whole moor provides a method for extensive surveys of red grouse, generating estimates of grouse population size at a moor level which can be directly related to management practices, particularly to harvesting and parasite control strategies.

Muskrats Ondatra zibethicus are considered a pest species in the Netherlands, and a year-round control programme is in effect. Currently, the agency responsible for the management of muskrat populations in the Netherlands (the LCCM) is preparing for field studies to compare alternative strategies of control. In order to decide on the specific design of such field studies, a population dynamic model was built. The model compares the current management strategy with alternatives in which the effort is focused in space or in time. The model allows us to prioritise future research questions. The major gaps in knowledge at this moment are: 1) insight into the costs of harvesting at different harvest rates, and 2) the relationship between population density on the one hand and (financial damage or) safety risk on the other hand. We suggest continuing the current management, and to test our hypothesis that intensifying harvest will lead to lower numbers of animals killed in the medium term than more extensive harvest rates. The muskrat control programme offers excellent opportunities for applied biological studies of which the benefits are likely to outweigh the costs.

Quantification of basic demographic parameters such as survival rates and cause-specific mortality is important for effective species management. We conducted a 4-year study (during May 2005-June 2009) of elk Cervus canadensis calf survival and cause-specific mortality in Pennsylvania, USA. We captured and radio-collared 93 elk calves ≤ 7 days old and monitored them weekly to detect mortality and cause of death. Of the 93 radio-collared elk calves, 15 (16%) died during our study. Despite high black bear Ursus americanus and coyote Canis latrans densities, none of the mortalities were the result of predation. Causes of death included poaching (N = 3), legal harvest (N = 2), road kill (N = 2), pneumonia (N = 1) and rumen acidosis (N = 1). We were unable to determine the cause of mortality for six of the elk calves; however, predation was eliminated as a possible source of mortality in all unknown cases. Survival probabilities were similar between sexes and among years. Summer survival (birth-31 October) was 0.92 (SE = 0.03, N = 93) and winter survival (1 November - 1 April) was 0.90 (SE = 0.04, N = 79). Annual estimated elk calf survival was 0.82 (SE = 0.04, N = 93). Our findings suggest that Pennsylvania elk calves have a > 80% chance of survival to one-year of age, despite high densities of predators known to influence elk calf survival elsewhere. The high calf survival rates that we observed indicate the availability of high quality habitat leading to excellent physical condition of elk.

Indices of diet quality are useful tools for research on the ecology, behaviour and the management of wildlife. The quality of diets is an essential driver of the performance of individuals, which in turn drives the dynamics of populations. Dietary nitrogen (DN) is a good index of diet quality in some herbivores, and faecal nitrogen (FN) has proved a good predictor of DN in grazers, but there is some doubt as to its validity in browsers, since they eat food with significant amounts of tannins, which bind with proteins. In order to test the validity of FN to predict DN, we first test for seasonal and spatial variations of FN in a population of roe deer Capreolus capreolus. Secondly, we examine the relation between DN and FN according to the occurrence of condensed tannin in the diets of 41 individuals of this population. Third, using feeding trials with captive roe deer, we test if free condensed tannins in diets affect the relationship between DN and FN. The results show that FN broadly follows seasonal and spatial variations of food quality, with higher values in spring, and higher values in roe deer living in a farmed area with richer food resources compared to those of deer in forests. Both in wild and captive animals, DN increases with FN when the dietary condensed tannin is low or absent, but the relationship disappears when there is an appreciable amount of condensed tannin in the diet (> 2%). We conclude that FN is not suitable for predicting individual short term diet quality for browsers that ingest significant levels of tannin. FN may, nonetheless, reflect broad seasonal and spatial patterns of diet quality at the population level.

We need to monitor wildlife populations to determine whether management goals are achieved and to improve future decisions. Therefore, it is important to evaluate the cost and accuracy of monitoring strategies in the context of management. Using a computer simulation of a harvested population, we tested the relative performance of three survey methods: aerial survey, pellet-group counts and hunters' observations, to inform about the management of Swedish moose Alces alces populations. Where more than one survey method was used in a single year, we used Bayes' theorem to combine information and estimate population size. We used two measures of performance: the fraction of time in which the population had an ‘undesirable’ size and inter-annual variation in harvest. Furthermore, we traded these performance measures against their cost. An annual aerial survey was the most costly monitoring method (27,000€) and maintained the population within the desired range 72% of the time. The least expensive monitoring strategy (hunters' observations; 1,600€) maintained the population within a desired range of 66% of the time. A combination of two relatively inexpensive survey methods (i.e. pellet-group counts and hunters' observations; at an expense of 10,000€) maintained the population within the desired range in 76% of the simulated years. Thus, a combination of annual pellet-group counts and hunters' observations performed better than annual aerial surveys, but was considerably less expensive. Furthermore, the annual combination of pellet-group counts and hunters' observations also performed best regarding the inter-annual harvest variation. Management actions only maintained the population within the desired range 81% of the time, even when population size was observed without error, mainly due to variable net growth rates. In wildlife management systems, where a variety of monitoring methods are used, the overall performance generally improves with monitoring expenditure, but very few studies explicitly account for expenditure. However, our study shows that combinations of inexpensive methods can reduce monitoring costs substantially while yielding an equal or an increased performance.

Knowledge of movements, range size and spatial overlap of sympatric deer is integral to understanding chronic wasting disease (CWD) in endemic areas and can assist resource managers in modeling the spread of the disease. We radio-collared 70 deer (30 mule deer Odocoileus hemionus and 40 white-tailed deer O. virginianus) in the North Platte River Valley in western Nebraska, USA, from 2004 to 2007 to document movements, size and spatial overlap of home range and resource selection of these sympatric species of deer. We compared home-range size and overlap and resource selection among male and female mule deer and white-tailed deer to examine relative use of space in order to understand the potential for indirect spread of CWD better. We identified forested, riparian habitats as high selection of use and these habitats could likely contribute to the potential spreading of CWD between sympatric deer that concentrate in these areas. We found that migration, size of home range of female mule deer, and similarities in resource selection could contribute to sustaining or spreading CWD in Nebraska. The role of female mule deer in the spread of CWD coupled with selection for riparian corridors by both species should be investigated further, because these factors may be a primary determinant of disease spread in the historical range of mule deer.

Masked boobies Sula dactylatra, like many other species of Sulidae, do not construct elaborate nests. However, their nest sites produce a characteristic ‘nest signature’. We found that these nest signatures could apparently be seen in freely available satellite images (Google Earth^TM) of the main island of Ascension in the south Atlantic. We verified that this was the case by comparing nest signatures detected on these satellite images with field reports of occupied nests. We found that the locations of these nest signatures determined from satellite images agreed closely with the coordinates of actual nests on the ground. We used this information to determine the position and size of a previously unreported masked booby colony on the island. Thus, we show that the presence and abundance of some species can be estimated using freely available satellite imagery if a suitable signature in the satellite image can be found. Regularly updated satellite imagery of target sites could also be used for population monitoring. While this would be expensive, initial evaluation of the technique for particular species or populations can be achieved using freely available images. We encourage wildlife managers to view their study sites on Google Earth^TM for evidence of their target species.

Translocation is a non-lethal practice used to manage carnivore-livestock conflicts. Nevertheless, its use has been questioned due to its low success rate and high cost. We performed a literature review to assess the effectiveness of translocation, human-related mortality and cost. We estimated the overall effectiveness to be 42% ± 6, felids were involved in 70% of the translocations and 80% of the case studies were conducted in North America and Africa. Human-related mortality accounted for the 83% of deaths after translocations. Translocation cost per individual was estimated at US$ 3,756 ± 357 (N = 16), a sum equivalent to compensate for up to 30 livestock heads. For conservation purposes, translocation is costly and less effective than other alternatives such as compensation with best herding practices.