Estimating ‘total counts’ of waterbirds from aircraft is a widely used survey method, and we assessed the effectiveness of this method for geese, ducks, waders and gulls by comparing the results of counts from aircraft with ground counts in the Danish Wadden Sea during 1984–1998. In total, 47 counts were carried out in 12 counting sites and the results were compared for 18 waterbird species, which varied in abundance, flock size and degree of aggregation. Significantly greater numbers of waterbird species were identified from the ground than from aircraft (mean number: 16.1 vs 10.6 species). Depending on the accuracy of aerial counts compared to ground counts, the species were divided into three categories: a) brent goose Branta bernicla, shelduck Tadorna tadorna, mallard Anas platyrhynuchos, eider Somateria mollissima and oystercatcher Haematopus ostralegus had a high level of correspondence between densities obtained from ground and aerial counts (detection rate of >80% with no statistical difference between slopes and intercepts of the observed regression lines and the ideal lines (x=y), differences between mean densities of ground and aerial counts being <15%); b) wigeon Anas penelope, teal A. crecca, grey plover Pluvialis squatarola, dunlin Calidris alpine, bar-tailed godwit Limosa lapponica, black-headed gull Larus ridibundus, common gull L. canus, herring gull L. argentatus, great black-backed gull L. marinus and common/arctic tern Sterna hirundo and S. paradisaea had a medium correspondence between densities obtained from the two platforms (detection rate of >55% with differences between the mean densities of ground and aerial counts of <30%; and c) redshank Tringa totanus, greenshank T. nebularia arquata and curlew Numenius arquata had a low correspondence between the densities obtained from the two platforms (detection rate of <55% and differences between the mean densities of ground and aerial counts of >30%). Species with a high and medium level of correspondence between the two platforms are mostly species that are numerous, of widespread occurrence, and found in large flocks. Species with a low correspondence are minority species, occurring scattered or in small flocks. We recommend to supplement aerial counts with ground counts at sites with mixed flocks of more dabbling duck species present to increase the accuracy of the count results.

We analyse the selection of denning habitats by Scandinavian brown bears Ursus arctos and test if there are differences related to sex and age. At the landscape level, the vegetation types within a 500-m radius around 250 dens used during 1990–2000 in south-central Sweden were analysed using a Geographical Information System (GIS). Compositional analysis (CA) was used to test if bears selected or avoided certain habitat types for denning. There were relatively few differences in habitat selection among bears of differences age or sex. Overall, as a group the bears showed distinct preferences in selection of denning habitats; selecting for open canopy (Scots pine Pinus sylvestris) forests and habitats with moist soil with rich vegetation, before closed canopy (older Norway spruce Picea abies and Scots pine) forests, young forest and clear cuts, mountain coniferous forests and bogs. Denning bears avoided water, alpine mountain-birch forest, deciduous forest, peat, exposed bedrock and gravel pits. Bears denned more on lower altitudes, easterly aspects and steeper slopes than was available. Furthermore, bears avoided intermediate-size roads, perhaps because they are the source of human disturbance, providing a combination of easy winter access (because they are ploughed) and relatively high traffic intensity.

Natural England receives an increasing number of complaints about problems caused by badgers Meles meles in urban and suburban environments, most of which concern problems caused by the digging of burrows (setts). The aim of our study was to identify factors related to the presence of badger setts in urban and suburban areas, in order to provide information relevant to the development of an urban badger management strategy. We identified habitat factors (including human population density) associated with the presence of badger setts in four extensively surveyed towns or cities in England, in a GIS-based approach using binary logistic regression analysis. Badger sett densities in urban areas were comparable to sett densities in most rural parts of the UK. Thus, badgers can achieve relatively high population densities in urban environments, despite the potential for human-badger conflict. The single most important factor predicting sett location was the type of habitat in which the sett in question was located, followed by the slope of the ground at that location. Sett presence was also predicted by the proximity of other setts, and badgers preferred areas with intermediate human population densities. The population density of badgers in urban and suburban environments appears to be mainly related to the availability of suitable places for locating setts, rather than to factors that would be expected to reflect food availability. This information will help to predict potential sites of badger-related problems and may be relevant to understanding the ecological requirements of other carnivore species that inhabit urban environments, such as red fox Vulpes vulpes, stone marten Martes foina and racoon Procyon lotor.

We investigated three main niche components (diet composition, habitat use and diel activity rhythms) to examine how the weasel Mustela nivalis and the stoat M. erminea, both specialised predators of small rodents, could permanently coexist in Belarus. Our research was carried out in temperate forests of Belarus, in two study areas with different environmental conditions: 1) continuous dry-land forest interspersed by a variety of swampy biotopes and aquatic ecosystems (Paazerre, northern Belarus) and 2) extended wetland with large forest patches (Palesse, southern Belarus). The habitat use and diel activity rhythms of seven weasels and eight stoats were analysed by radio-tracking over about 300 km² in Paazerre. Snow-tracking was also applied to study habitat use by the two mustelid species. Diet composition was examined by analysing 365 weasel scats and 606 stoat scats. Our results suggest that while the weasel and stoat occur in close proximity to each other, they use different micro-habitats, are most active during different times of the day, and prey primarily on different small rodent species. Most weasels selected forest and forest edge habitats, where they predominantly preyed on smaller rodent species (bank voles Clethrionomys glareolus and Apodemus mice); stoats selected wetlands, especially open grassy marshes, and preyed more frequently on larger rodents such as water voles Arvicola terrestris and Microtus voles. Weasels were mostly diurnal and adjusted their activity to the seasonally changing length of daylight, whereas stoats were much more active in twilight and during the night.

The southern river otter Lontra provocax is an endangered species. It has a patchy distribution in southern Chile and Argentina, inhabiting both freshwater and marine habitats. While most studies of their diet and habitat use have been carried out in freshwater habitats, our study is the first one on these aspects in a predominantly palustrine wetland. In southern Chile, the Boroa wetland may be the only wetland with southern river otters and five different subsystems: palustrine open water, swamp forest, seasonal and permanent marshes, and riverine associated with open farm fields. We studied these five different subsystems during April 2003 - May 2004, and collected and analysed 194 spraints in order to assess the effect of rainfall and subsystems on the diet and sprainting behaviour of southern river otter. The river otter's diet primarily consisted of crustaceans; however, rainfall and wetland subsystems influenced the frequency of fish and especially amphibians in the spraints collected. This is the first study documenting the helmeted water toad Caudiverbera caudiverbera as a prey of southern river otter. Southern river otter visited latrines located within the swamp forest more frequently, as this subsystem may provide refuge for latrines and dens as well as an important supplementary feeding resource. Our study provides insights into the role of coastal wetlands in predation processes, and highlights the importance of ecosystem services derived from wetland for biodiversity conservation. However, it is of concern that these wetlands are increasingly affected by drainage for agriculture and other landscape changes in southern Chile.

In the sport hunting of pumas Puma concolor, most states and provinces of the United States and Canada do not allow the killing of females with kittens. However, female pumas can be away from their kittens and, if detected by hunters at these times, can be mistakenly killed. To assess the extent to which females with kittens might mistakenly be killed we need to have estimates of the percent of time female pumas are with their kittens on a daily basis. Previous estimates range within 52-83%, but are based on simultaneous locations taken during the day when pumas are least active. To provide a more accurate assessment of the amount of time females spend with their young, we analyzed telemetry data collected over 24, 24-hour blocks for 15 females and their kittens. We collected data from June to September during 1989-1999 in southeastern Idaho and northwestern Utah. We found that females with 7-12 month-old kittens were within 200 m of their kittens an average 16.2±3.8% (N=12) of the time. These females were >1.0 km from their kittens 30.9±6.7% of the time. Three females with kittens in dens were near their dens 10.3, 12.2 and 2.3% of the time. Females were within 200 m of their kittens the least amount of time (5.1±2.1%, N=8) during 11:00-14:30 and the most amount of time during 23:00-01:30 (29.4±3.0, N=6) and 07:00–10:30 (23.2±3.1%). We conclude that the probability that a hunter would encounter a female without her kittens was >80%.

Different ungulate species that co-occur over evolutionary time have been hypothesized to develop mechanisms to limit the degree to which they directly compete for the same limited resources (i.e. resource partitioning). In situations where an exotic ungulate has been recently introduced to a system, resource partitioning has not likely developed; this appears to be the situation between introduced feral ass Equus asinus and indigenous mountain sheep Ovis canadensis in the Sonoran Desert of southeastern California, USA. We analysed data from aerial surveys conducted during 1993–2003 to look for evidence of an effect of feral ass abundance on mountain sheep demography. After controlling for the influence of forage availability via rainfall, we found no evidence of relationship between an index of feral ass abundance and indices of reproduction or recruitment in mountain sheep (P≥0.360). However, we found strong evidence for an effect on indices of sheep abundance and population rate of change. There was an interactive effect of rainfall and feral ass, such that a negative relationship between abundances of mountain sheep and feral ass was strongest during the driest years (P=0.014). There was a negative relationship between rate of change for sheep populations and feral ass abundance (P=0.016), which was not affected by rainfall. These results indicated a competitive effect of feral ass on mountain sheep populations, but the mechanism of competition remains unclear. Further research should use manipulations in feral ass abundance to clarify interactions between these species.

Use of food resources by herbivores depends on intrinsic constraints, essentially body size and morpho-physiological characteristics, which determine the range of foods they tolerate and environmental constraints, such as seasonality and interspecific interactions, which determine the availability of resources. We analysed a collection of rumen contents samples from sympatric populations of red deer Cervus elaphus and roe deer Capreolus capreolus and tested several theoretical predictions relating to the impact of intrinsic and environmental constraints on diet composition, diversity and similarity. Red deer consumed more slowly digestible, fibrous forage than roe deer and had a more diverse diet throughout the year, which supports predictions deriving from specific body size and morpho-physiological characteristics. In conformity with the optimal foraging theory, both species consumed more slowly digestible forage in times of low food availability (i.e. during winter) than during the rest of the year. An increase in diet similarity in winter, along with predictions from the theory on competitive interaction processes, led us to assume that food resources were not limiting and that exploitative competition between red and roe deer was unlikely in our study area. We underline the importance of studies of the use of food resources by sympatric herbivores in answering applied ecological questions at the local scale, and we suggest that the Euclidean geometrical approach we used is particularly well suited for the analysis of resource matrices, a common end-product of long-term field data gathering on the feeding habits of animals.

The instantaneous rate of food intake for mammalian herbivores is controlled by the geometry of plant communities which regulates the encounter rate with bites, bite mass and the processing rate of bites. The geometry of plant canopies is fractal because bite density only occupies a fraction of the entire dimension of the tree canopy and scales allometrically with the search resolution of herbivores. We tested the hypothesis that both the population density of moose Alces alces and site productivity alter the fractal geometry of plant canopies as well as bite mass, and therefore the mechanisms regulating herbivore functional response. Sapling birch Betula pubescens and B. pendula and Scots pine Pinus sylvestris in northern coastal Sweden were sampled in five exclosures that spanned the range of site productivities for the region. Within each exclosure and over four years, the effects of four population densities of moose (0, 10, 30, and 50 moose/1,000 ha) were experimentally simulated within treatment plots. The fractal dimension of bite density of Scots pine decreased non-linearly with increasing moose population density regardless of site productivity. In contrast, the fractal dimension of bite density for birch increased strongly from low to intermediate moose densities regardless of site productivity, but decreased with further increases in moose population density. For birch, the decreases in fractal dimension were greater on sites of low productivity. Bite mass decreased linearly with increases in experimental moose density for both species, but the decrease was moderated by increases in site productivity. The different geometric responses of birch and Scots pine saplings to moose population density resulted in an increase in predicted plant biomass for birch, a decrease in plant biomass for Scots pine, and decreases in predicted herbivore intake rate for both species with increased moose population density. Thus, there are strong feedbacks between population density, site productivity and the geometry of plant canopies regulating herbivore functional response.

Age-specific body mass and % lactation are indices commonly used to monitor status of cervid populations relative to carrying capacity. However, prior-year body condition and reproductive status may influence these indices and alter their interpretation. We examined variation in body mass and % lactation among cohorts of female white-tailed deer Odocoileus virginianus to determine: 1) patterns of variation among age classes, 2) if cohorts compensated in subsequent years for restricted somatic development, and 3) the relationship between body mass and % lactation within cohorts. Body mass and % lactation of young deer were more variable than for older deer, potentially making them a more sensitive indicator of population status relative to carrying capacity. The lack of correlation in body mass of cohorts across years implies that cohorts can compensate for restricted somatic development during subsequent years in the environments we studied. Body mass and % lactation were positively correlated in 1.5-year cohorts, suggesting that age of primiparity was affected by body condition. However, mean cohort body mass did not influence % lactation in older cohorts. Our data support that older cohorts (≥3 years old) have greater resiliency to changes in density or to environmental events as these cohorts demonstrated less annual variation in body mass and % lactation than did younger cohorts. Annual changes in morphometrics and fecundity of younger-aged cohorts may be the best indicator of animal density relative to carrying capacity, or of environmental events that influence carrying capacity.

We compared survival of neonate white-tailed deer Odocoileus virginianus captured using vaginal-implant transmitters (VITs) and traditional ground searches to determine if capture method affects neonate survival. During winter 2003, 14 adult female radio-collared deer were fitted with VITs to aid in the spring capture of neonates; neonates were captured using VITs (N=14) and traditional ground searches (N=7). Of the VITs, seven (50%) resulted in the location of birth sites and the capture of 14 neonates. However, seven (50%) VITs were prematurely expelled prior to parturition. Predation accounted for seven neonate mortalities, and of these, five were neonates captured using VITs. During summer 2003, survival for neonates captured using VITs one, two, and three months post capture was 0.76 (SE=0.05; N=14), 0.64 (SE=0.07; N=11) and 0.64 (SE=0.08; N=9), respectively. Neonate survival one, two and three months post capture for neonates captured using ground searches was 0.71 (SE=0.11; N=7), 0.71 (SE=0.15; N=5) and 0.71 (SE=0.15; N=5), respectively. Although 71% of neonates that died were captured <24 hours after birth using VITs, survival did not differ between capture methods. Therefore, use of VITs to capture neonate white-tailed deer did not influence neonate survival. VITs enabled us to capture neonates in dense habitats which would have been difficult to locate using traditional ground searches.