Northern pintail Anas acuta (hereafter pintail) populations wintering within Suisun Marsh, a large estuarine managed wetland near San Francisco Bay, California, USA, have declined markedly over the last four decades. The reasons for this decline are unclear. Information on how hunting and other factors influence the selection of vegetation types and sanctuaries would be beneficial to manage pintail populations in Suisun Marsh. During 1991-1993, we radio-marked and relocated female pintails (individuals: N = 203, relocations: N = 7,688) within Suisun Marsh to investigate habitat selection during the non-breeding months (winter). We calculated selection ratios for different vegetation types and for sanctuaries, and examined differences in those ratios between hunting season (i.e. hunting and non-hunting), age (hatch-year and after-hatch-year), and time of day (daylight or night hours). We found that diel patterns in selection were influenced by hunting disturbance. For example, prior to the hunting season and during daylight hours, pintails selected areas dominated by brass buttons Cotula coronopifolia, a potentially important food source, usually outside of sanctuary boundaries. However, during the hunting season, pintails did not select brass buttons during daylight hours, but instead highly selected permanent pools, mostly within sanctuaries. Also, during the hunting season, pintails showed strong selection for brass buttons at night. Sanctuaries provided more area of permanent water pools than within hunting areas and appeared to function as important refugia during daylight hours of the hunting season. Wildlife managers should encourage large protected permanent pools adjacent to hunted wetlands to increase pintail numbers within wetland environments and responsibly benefit hunting opportunities while improving pintail conservation.

In order to monitor bat population trends, an annual census is performed of all known underground hibernacula in Europe. During these censuses, bats are sometimes found to show signs of arousal, presumably from non-tactile stimuli caused by the observer, e.g. air currents, sound, light or an increase in temperature. We assume that heat and/or light from a torch can play a role in awaking hibernating bats. Observers use different light sources, which produce different amounts of heat. We experimentally tested the heat produced by three commonly used torches: two incandescent torches (krypton and halogen) and one LED torch. We performed the experiment on 28 January 2007 in an old brick kiln in Windesheim (Overijssel Province, the Netherlands), which is used by hibernating bats. The results show that temperatures in a crevice significantly increased when using the ‘hot’ incandescent torch types. The effect of these torches on both air and surface temperature was significant after both 10 and 30 seconds. Under the assumption that an increase of the ambient temperature by 5°C or more can cause a bat to arouse from torpor, we conclude that using ‘hot’ torches such as incandescent (halogen) lights poses a risk to the animals under study. To minimise heat disturbance from light sources, we recommend LED torches as the best available alternative.

We investigated the fate of seeds of five tree species hill cherry Prunus jamasakura, Korean hill cherry P. verecunda, Japanese bird cherry P. grayana, giant dogwood Swida controversa and crimson glory vine Vitis coignetiae in the faeces of the Asiatic black bear Ursus thibetanus in a temperate forest in central Japan. Clarifying the fate of seeds dispersed by endozoochorous seed dispersers will enhance assessments of their roles as primary seed dispersers. We established several experimental treatments in the field. Each faeces sample was covered by cages with different mesh sizes which limited accessibility by animals (NM: no mesh, SM: 1 mm mesh and MM: 10 mm mesh). We examined whether seed removal varied among tree species and between mesh-size treatments from 2004 to 2007 (N = 625 samples). We set up an automatic camera trap 1.5 m above the ground at all NM treatments. In the NM treatments, the number of seeds of all tree species decreased immediately after the faeces were set. In June of the following year, < 1% of the seeds from any species remained in the vicinity of the faeces. However, we found 3.0-13.2% intact seeds of all species in the soil below the faeces, as well as within a 10-m radius around the faeces. In the NM treatments, most seed removals were observed within four days after the faeces were set. For all tree species in the MM treatment, most of the seeds were present on the surface of the soil, and 1-2% of the seeds germinated at the location where faeces were set. In the SM treatment, none of the seeds from any of the tree species disappeared and germinated. We took a total of 415 photographs at the NM sites, 97.8% of which were of rodents either holding or eating seeds. Many of the seeds contained in the bear faeces were removed and eaten by rodents. However, 2.1-5.1% of the seeds survived and germinated, which implies that rodents may also act as secondary seed dispersers.

Sufficient energy reserves are crucial to the overwinter survival of northern non-hibernating mustelids. We sought a reliable index of body condition (fatness) in harvested populations of wolverine Gulo gulo, based on the relationship between fatness and the mass of distinct fat depots extractable by necropsy. Fatness did not differ significantly between genders or winter months, nor was it significantly related to body size or age. Using a first group of 18 males and 14 females, we developed predictive least-square linear regressions between fat depots (popliteal, sternal, omentum, mesenteric and perirenal) and fatness (g fat/100 g body mass) using skinned carcasses provided by fur trappers in the Yukon, Canada. Fatness was consistently better predicted in females than in males. Fatness was best predicted by the sternal fat depot (R² = 0.73) in males and by the omentum as well as sternal fat depots in females (R² = 0.94 and 0.87, respectively). We then compared known fatness and fatness predicted from regressions of the sternal fat depot using a second group of 14 males and nine females, and mean fatness did not differ significantly. We suggest that, due to its ease of extraction and predictive power, the sternal fat depot is a valid fat index with both sexes of wolverine, although it (or any other fat depot) should be used with caution with males, which seem more prone to obesity. This new index will help wildlife managers monitor changes in body condition of wolverines in response to changes in environmental conditions.

The estimation of animal abundance has a central role in wildlife management and research, including the role of badgers Meles meles in bovine tuberculosis transmission to cattle. This is the first study to examine temporal change in the badger population of Northern Ireland over a medium- to long-term time frame of 14-18 years by repeating a national survey first conducted during 1990-1993. A total of 212 1-km² squares were surveyed during 2007-2008 and the number, type and activity of setts therein recorded. Badgers were widespread with 75% of squares containing at least one sett. The mean density of active main setts, which was equivalent to badger social group density, was 0.56 (95% CI: 0.46-0.67) active main setts per km² during 2007-2008. Social group density varied significantly among landclass groups and counties. The total number of social groups was estimated at 7,600 (95% CI: 6,200-9,000) and, not withstanding probable sources of error in estimating social group size, the total abundance of badgers was estimated to be 34,100 (95% CI: 26,200-42,000). There was no significant change in the badger population from that recorded during 1990-1993. A resource selection model provided a relative probability of sett construction at a spatial scale of 25 m. Sett locations were negatively associated with elevation and positively associated with slope, aspect, soil sand content, the presence of cover, and the area of improved grassland and arable agriculture within 300 m.

Influential factors associated with population dynamics of mountain lions Puma concolor include exploitation rates, prey availability, habitat structure and social structure. Throughout most of North America, mountain lion harvest is regulated by state or provincial quotas or is protected by federal laws. In Texas, however, they are not classified as a game or fur-bearing animal so their harvest is not regulated. To better understand the differences between population characteristics of mountain lions in west Texas (WTX) and south Texas (STX), we initiated two ecological studies. We captured, radio-marked and monitored mountain lions to ascertain survival, mortality factors, density, reproduction and population structure. We captured and monitored 19 and 21 mountain lions in the STX and WTX study sites, respectively. Average densities (No/100 km²) were different between our two study sites (STX = 0.269, WTX = 0.427) and were considerably lower than in previous studies. Mortality factors also differed between the two areas; in STX the causes were predominantly hunter harvest compared to trapping in WTX. Seasonal survival rates of mountain lions were lower during the general hunting season (STX = 0.783, WTX = 0.750) than during the non-hunting season (STX = 0.962, WTX = 0.931). Because population characteristics differed between the two genetically separated populations (Walker et al. 2000), resource managers should consider evaluating regional, rather than statewide management plans for mountain lions in Texas.

European silver fir Abies alba is the most heavily browsed conifer in Central European mountain forests. Attempts to reduce ungulate browsing have often been unsuccessful, controversial or too costly. The aim of the work described here was to improve our understanding of the factors that lead to browsing on silver fir. The silver fir content in the diet of three sympatric ungulate species, chamois Rupicapra rupicapra, red deer Cervus elaphus and roe deer Capreolus capreolus, was determined by microhistological analysis of faeces collected at four sites in the Alps. Further, the supply of silver fir was assessed at the individual tree and patch scale and then extrapolated to site scale. Silver fir consumption was highest in winter, when diet composition varied among sites but not among ungulate species. Towards the summer, site-differences decreased and differences among ungulate species increased. Red and roe deer reduced consumption of silver fir, whereas chamois kept it constant. The use of silver fir was unrelated to the supply at the various sites, but increased with the proportion of trees growing amidst palatable herbaceous species. At the individual plant scale, ungulates browsed on the saplings with the larger needles. These results indicate that silver fir as food does not rank high among the available plant species, but is eaten opportunistically, especially when it grows close to more preferred food plants. However, when alternative food is scarce, particularly in winter, it may also represent a shortage food supply, and larger quantities are consumed. Yet, the fact that feeding on silver fir is mostly opportunistic may offer forest managers a way to approach the ‘browsing problem’.

With climate change, modelling has suggested that increased inaccessibility of forage through snow may endanger some populations of arctic ungulates; however, contemporaneous data on snow-cover conditions, other ecological factors and ungulate responses are lacking at the landscape scale. Researchers have increasingly used remote sensing to map snow cover with higher accuracy, but such tools have not been utilized in research and management of arctic ungulate populations. We estimated field-measured percent snow-covered area (F-SCA) in wintering areas of endangered Peary caribou Rangifer tarandus pearyi in the Bathurst Island complex (BIC) and developed a threshold for a normalized difference snow index (NDSI) using Landsat data. We used our NDSI threshold and another threshold to estimate snow-covered area (SCA) in Peary caribou habitats in the BIC during 1993-2003, compared these estimates with snow data from the nearest weather station and assessed the adequacy of Landsat data for arctic ungulate research. Our calculated NDSI threshold of 0.70 reflected field observations better than the published threshold, and our estimated SCAs showed greater variation between study areas, between years and during snow melt. Estimated SCAs were not correlated with total snowfall or snow depth at the nearest weather station. We conclude that SCA using remotely-sensed data for ungulate habitats would be more useful than weather-station data. Our methods could detect winters with relatively mild snow-cover conditions, but not those with very severe conditions; therefore, we recommend development of NDSI thresholds corresponding to ≥ 75% F-SCA, instead of ≥ 50%. NDSI-derived SCA methods should prove more useful for southerly arctic regions where sun angles would be less limiting than in the BIC. Higher resolution imagery may be more suited than Landsat for the assessment of snow cover in arctic ungulate ecology. With climate change, further development of remotely-sensed indices of snow cover, such as NDSI and SCA, should enhance our understanding of how arctic ungulates may or may not adapt.

Damage caused by wildlife foraging can lead to significant agricultural losses and the problem can be further complicated if the damage-inducing animal is a valuable resource in its own right. Provision of alternative food sources such as cover crops might be a means of reducing the damage which appears to be linked to scarcity of alternative foods in intensively-managed agroecosystems. Cover crops may provide other benefits to agroecosystems, i.e. preventing soil erosion but can potentially have some undesired consequences, i.e. water competition with the cash crop. In our study, we tested the effectiveness of cover crops in reducing the damage caused by foraging European rabbit Oryctolagus cuniculus to vineyards in a semi-arid agroecosystem in southern Spain. Experimental treatments consisted of a combination of the presence/absence of sown cover crops (70% oat Avena sativa and 30% garden vetch Vicia sativa) with/without rabbit exclusion. In the 2009 growing season, we assessed rabbit-induced damage using a browsing index on vine shoots, rabbit use of plots was estimated based on faecal pellet counts and grapevine yield was measured at harvest. Rabbits ate the cover crops, and rabbit use was highest in the plots sown with the oat and vetch cover crop. However, the effect of the presence of the cover crop on the amount of damage caused by rabbits was limited and, moreover, the presence of the cover crop had a negative effect on grapevine yield. Exclosure fences effectively reduced rabbit damage by keeping rabbit densities close to zero, but even a low rabbit number (∼ 1 rabbit/ha) can cause significant damage. Although cover crops provided rabbits with an alternative food source, they acted as attractants for rabbits and were not effective in reducing the damage caused to vineyards by higher rabbit numbers. Therefore, adding cover crops might not be an effective measure in controlling rabbit-induced damage in semi-arid wine-growing regions.

Translocating European ground squirrels Spermophilus citellus has become a popular conservation tool. However, few release techniques have been carefully evaluated. To contribute to an evidence-based ground squirrel translocation guide for wildlife managers, we evaluated conditions of habitat manipulation (grass height and artificial burrow entrance angle) which we expected to affect settlement of translocated ground squirrels during the critical period after release. In a field experiment, we translocated 173 individuals in southeastern Hungary in 2007. We released the animals into angled or vertical artificial burrows and manipulated grass height. We found that animals preferred angled (∼ 30°) artificial burrows, which facilitate digging, and medium-height grass (18 cm ± 1.5). Moreover, although ground squirrels generally are associated with short grass habitats, overhead protection by grasses is valuable after a translocation. This result implies that in order to accomplish a translocation, it is not sufficient to only know the habitat preference of a species in undisturbed situations, but also how and to what extent habitat characteristics should be manipulated to increase the chances of success.

Unknown causes of heterogeneity in the presence or detection of wildlife tracks and other signs could bias interpretations of population indices derived from surveys. These surveys can be the basis of management decisions for populations of wildlife. However, we know very little about potential biases affecting the presence of tracks in the landscape. We used an Information Theoretic Model Comparison approach to investigate the role of environmental, demographic and behavioural influences on the presence of river otter Lontra canadensis snow tracks in central British Columbia, Canada, from January to March 2008. We repeatedly located five radio-collared otters and recorded the presence of tracks within an estimated 100-m radius of the otter's location. We used combinations of five variables to develop logistic regression models that predicted the presence or absence of snow tracks when the location of otters was known. The presence of snow tracks was best described by a model containing covariates for gender and movement distance per day. The probability of detecting snow tracks was higher for male compared to female otters and was positively related to the daily movement distance of the individual animal. Track-sign heterogeneity among individuals could bias surveys that assess and monitor river otter populations, and should be incorporated into the design and interpretation of track surveys.