A three-year field-based study of 85 radio-tagged female wild grey partridges Perdix perdix was undertaken during 2001–2003 in East Anglia, England, to investigate possible links between chick diet and parasite-induced disease. The females produced 30 broods, whose diet measured by faecal analysis was typical of that previously reported. Chicks in some broods, however, consumed large numbers of known parasite vectors, particularly ants. Survival to the age of six weeks of chicks in a brood declined, on average, as the percentage of ants in the diet increased. Additionally 79 wild partridges found dead or in poor condition were submitted for necropsy to assess internal parasite burdens. Of these, 22 (28%) contained parasitic infections, although only 12 (15%) had levels of parasites that may have resulted in death. Internal parasites were found in only 7% of a subsample of 46 birds that died accidentally or were shot, and this was likely to be representative of the background level of infection. In a separate laboratory study of nutrition, no parasites were recorded in 180 six-week-old chicks that had eaten > 16,000 potential parasite vectors during the first three weeks after hatching. Either parasite levels were very low among host invertebrates or other factors contributed to increase disease susceptibility. Our results suggest that poor wild brood survival was indicative of low habitat and food quality rather than of a high rate of parasite infection. Management to conserve and increase wild grey partridge numbers should concentrate on improving foraging habitat quality, i.e. increasing the abundance of nutritious invertebrate chick-food, rather than directing efforts at reducing the small-scale effects of disease.

We investigated spacing patterns of Pyrenean grey partridges Perdix perdix hispaniensis during the breeding season (March-September) to refine our recommendations concerning restoration of nesting and brood rearing habitats. The study was based on 30 grey partridges, 24 yearlings (19 males, five females) and six adults (five males, one female) radio-monitored in two study areas of the eastern Pyrenees. Movements and home ranges were analysed for the pre- and post-hatching periods. For each bird and period, we used cluster analysis to identify core areas within home ranges. Throughout the breeding season, 24 of the 30 birds were paired and six yearling males remained unpaired. The latter used larger home ranges than paired birds, at least before hatching. The home-range size (Minimum Convex Polygon) of the 24 pairs averaged 118 ha in spring (from pair formation to hatching) and 126 ha in summer (brood-rearing period). Pairs tended to use larger core areas after hatching (mean = 10.8 ha) than before (mean = 6.2 ha). After hatching, broodless pairs used larger core areas (mean = 14.4 ha) than those with broods (mean = 8.7 ha). For both groups, we found little overlap between core areas used before and after hatching. For unsuccessful breeders, the small overlap was associated with post-breeding movements to higher altitudes. For successful breeders, it was related to movements to brood rearing habitat. Daily inter-fix distances of broods averaged 126 m during the first three weeks after hatching, then regularly increased up to 249 m as chicks exceeded the age of six weeks. The size of core areas used by broods indicates that treatment plots should cover 5–10 ha to restore breeding habitats with a diversity of shrubland vegetation types.

We examined an index of abundance for rabbits Oryctolagus cuniculus involving a spotlight plot count (SPC) using capture-mark-resighting as a reference method in five study areas. In these areas, density varied over a wide range, from 0.7 to 23.4 rabbits/ha, which is representative of most European populations. The SPC precision was good, as the coefficient of variation ranged within 5-54%, the median value being 17%. We showed area and year effects on the index and a significant relationship between the SPC and ln(density) (P < 0.0001). The logarithmic relationship between density and SPC suggests a saturation of the index when density increases. Despite the fact that the SPC index was highly correlated with density, its ability to detect population changes was rather poor. This lack of sensitivity may be due to factors affecting rabbit detectability such as climatic conditions, lunar phases, observers, changes in crop rotation and, more generally, to factors affecting the number of rabbits above ground at the time of the count. The area effect means that the index is not suitable for comparing data recorded in different areas. The year effect is an actual obstacle to the use of this index since, within a defined area, the temporal changes in the index values are not related only to the estimated density. Our study highlights the necessity to validate abundance indices against reference methods so as to check their ability to detect changes in population size and their suitability for comparing data from different areas.

In Scandinavia, suspected hybrids between the native mountain hare Lepus timidus and the introduced brown hare L. europaeus have been observed by hunters since the first introductions of brown hares in the late 19th century. Several attempts to verify the status of these suspected hybrids have been unsuccessful. Recently, however, the transmission of mitochondrial DNA (mtDNA) from mountain hares to brown hares was documented and interpreted as a consequence of hybridisation and subsequent introgression. However, mtDNA markers alone will not allow identification of first-generation hybrids because of the strictly maternal inheritance of mitochondria. Here, we combine mtDNA data with analyses of variation in seven microsatellite loci among brown hares, mountain hares and putative hybrids. Our purpose was to determine species differentiation in nuclear DNA markers, elucidate the extent of interspecific gene flow, identify true hybrids within our sample and evaluate the ability of hunters to identify hybrids. The estimated genetic difference between species was low (F_ST = 0.18 – 0.24, Rho_ST = 0.09 – 0.16). We believe these low estimates result from a reticulated mode of evolution among hares, with repeated gene flow over the species barrier. Population assignment tests and randomly assembled, artificial, hybrid genotypes were used to classify individuals independently from the morphologically assessed species identity. More than half (57%) of the putative hybrid specimens were assigned unambiguously to either species and first-generation hybrids seem to be rare. Morphological plasticity and backcrossing, which confound species identification within the genus Lepus, might explain invalid classifications by hunters.

Recent legislative changes to red fox Vulpes vulpes control practices in Britain have focussed attention on the possible impact of fox predation on economically and ecologically important species in agricultural landscapes. We compared the estimated mass of prey consumed annually against the pre-breeding biomass of prey species on a farm in southern England. Medium-sized mammals (mainly rabbits Oryctolagus cuniculus) dominated fox diet in all seasons (74% of mass ingested); birds (mainly pheasants Phasianus colchicus), small mammals (mainly field voles Microtus agrestis) and large mammals comprised 11, 7 and 6% of the diet, respectively. The mass of rabbits, wood mice Apodemus sylvaticus and bank voles Clethrionomys glareolus taken did not exceed the respective spring biomasses, indicating that fox predation was unlikely to be a significant limiting factor as all three species have a high rate of productivity. The impact on field voles was equivocal: the total mass consumed annually by foxes was equivalent to 2.7–5.7 times the estimated spring biomass, but this level of predation could be offset by recruitment. However, as field voles are a major dietary component of many predators and are likely to be confined to isolated habitat patches, the impact of predation on this species warrants further investigation. Predation on pheasants was equivalent to 34–81% of the estimated spring biomass: estimated levels of productivity derived from the literature would not have been sufficient to maintain pre-breeding population size. However, annual losses appeared to be fully compensated by immigration of reared birds from neighbouring farms. Predation on other avian taxa appeared insignificant.

I systematically sampled American marten Martes americana presence in two large study areas in the Selkirk and Purcell Mountains of southwest Canada using hair removal traps and tracks in snow. Both study areas were mostly forested and contained a broad cross-section of stand ages including abundant early seral and mature forest. I extracted measures of forest structure and dominant tree species, climax ecosystem types and human use from digital resource databases and used multiple logistic regression to model habitat selection of martens. I summarized data in windows of 100 m to 10 km in radius around each sample location to investigate the effect of varying data resolution on habitat selection. Marten detection at hair sites was positively related to temperature and trap duration and negatively related to snowfall while the trap was set. Martens were detected in all habitats sampled including recently logged areas, regenerating stands, dry Douglas-fir Pseudosuga menziesii forest and subalpine parkland. Overall selection was mildly greater using mean habitat values in 100 m and 2 km radius windows for both study areas. Martens selected for greater crown closure and older stands at the finer resolution; no selection for forest structure was detected at the larger resolution except that martens selected against increased overstory heterogeneity as measured by the standard deviation of crown closure (within the window). Martens preferred coniferous stands over deciduous dominated stands and were more abundant in wetter than in dryer ecosystems. Selection for ecosystems and stand types was stronger in the larger window size. At the intensity sampled in this study, neither road density nor logging appeared to affect marten habitat selection when I accounted for variation in ecosystems and stand structure. This study examined habitat selection at relatively coarse scales; stronger associations with forest structure may be expected at finer scales. In addition, roads or logging may influence habitat selection below the scale of my analysis.

Depredation on livestock is one of the main conflicts associated with Eurasian lynx Lynx lynx conservation in Norway. Our study investigates how Eurasian lynx utilise high-density patches of free-ranging and unguarded livestock (domestic sheep Ovis aries and semi-domestic reindeer Rangifer tarandus) as compared to patches associated with low-density wild ungulate prey, roe deer Capreolus capreolus. We monitored 10 radio-collared lynx in central Norway in two seasons that differed in ungulate distribution and density. According to the 'optimal foraging theory' an animal should preferentially utilise areas with more abundant food if not constrained by other factors; therefore we predicted that lynx should select patches containing livestock. Contrary to our prediction the results indicate no selection for livestock patches in any season. In contrast, a clear preference was shown for roe deer patches in both seasons. Our findings support the hypothesis that lynx depredation on livestock seems to be affected by chance encounter rates, rather than by active selection for livestock-dense patches. We conclude that habitat selection by lynx seemed to be governed by a number of other factors than food alone, and that lynx predation on livestock, especially on sheep, should not be regarded as being ecologically equivalent to predation on wild prey.

Increasing evidence suggests that conditions in early life have important consequences for ultimate body size and fitness. Skeletal parts are often used as retrospective indices of body size and growth constraints because of their resistance to seasonal variation in resource availability. Yet, slow-maturing bones are poor predictors of resource limitations during early development, as later benign conditions may lead to compensatory growth. We analysed the temporal growth dynamics of different sections of the lower jaw of roe deer Capreolus capreolus and found that the medioanterior section of the lower jaw reaches 95% of asymptotic size already at 2–4 months post partum, whereas the posterior section reaches 95% of asymptotic size at 14–16 months post partum. Hence, the size of the medioanterior section of the lower jaw is only dependent on resource availability in utero and the first few months post partum and, as such, potentially leaves a fingerprint of prenatal growth conditions that is evident even in adult individuals. This supports earlier findings in ungulates of a shift in skeletal growth spurts after weaning, and suggests that the choice of skeletal index for population and cohort studies is not trivial.

Censusing wild populations and detecting trends in population size over time is an important task in the conservation and management of wildlife. We compared two methods used to monitor numbers of chamois Rupicapra rupicapra and R. pyrenaica in two contrasting populations, and explored the relationship between the sampling effort and the repeatability of the results using resampling methods. One population in the Alps had been stable at a high density for several years, whereas the other population, located in the Pyrénées, was increasing exponentially, following a reintroduction. In both sites, a long-term monitoring programme based on individually marked chamois, allowed us to estimate population size using capture-mark-recapture methods (CMR). In addition, we calculated an index of population size as the mean number of animals observed on a foot transect surveyed repeatedly. We then compared whether trends estimated by each method were consistent. In the increasing population, both the index and the CMR estimates revealed an exponential increase in population size. In the stable population, neither the index nor the CMR estimate revealed any trend in size. Consistent results between the index and the CMR suggest that the index could be used to monitor trends in population size. Resampling techniques, however, pointed out that the index is only reliable when calculated over a sufficient number of surveys per year (10 in the Pyrenees, three in the Alps) and over a sufficient number of years of monitoring (about five years).

The chiru or Tibetan antelope Pantholops hodgsoni has dramatically decreased in number over recent decades, and efficient monitoring of the density and distribution of chiru is vital to the management of this endangered species. We evaluated line transect sampling methodology, using track and cross-county transects, and assessed its conformity to underlying assumptions for use in estimating density of chiru in the ca 2,300 km² Aru Basin, Tibet. Although violations of some assumptions were apparent, they were generally not substantial, and simple adjustments of sampling design can reduce their effects in future surveys. Sampling effort was not sufficient to demonstrate clear seasonal differences in chiru density between summer and autumn. However, cross-country transects on the west side of the study area did show a statistically significant higher autumn than summer density, and encounter rates (the number of detections per km) were significantly higher for both transect types in autumn. We tested for an expected negative bias associated with track transects, and although a clear difference in estimated density was not found, a significantly higher encounter rate was present for cross-country than for track transects. With increased sampling effort and a more effective design in future surveys, line transect sampling will be a useful methodology for assessment of chiru populations.

The dynamics of ungulate populations depend not only on the size, but also on the sex- and age-structure of the population. Successful management therefore depends on obtaining estimates of the age composition. Variation in performance due to age can be fairly well described by stages, and simple, rough methods for ageing cervids can therefore be useful to management. We assessed the performance of three relatively simple and objective methods based on tooth wear (height of molar), weight of eye lenses and diameter of pedicles (males only) on a sample of 77 female and 81 male European roe deer Capreolus capreolus from Lier, Norway. The relationship between tooth wear and age was linear, whereas the relationship between weight of eye lenses and diameter of pedicles was curvilinear with age, likely making them unreliable for old age classes. However, as only three males and six females ≥ 6 years old were included, we were unable to assess the uncertainty in age estimation for older age classes precisely. No simple method could precisely age roe deer, even up to five years of age. Our results do suggest that tooth wear, i.e. height of molar, can serve as a very simple and objective measure of age in roe deer, given that moderate precision (an error rate of ± 1 year and a success rate of 70% up to four years of age) is sufficient to reach management aims. As residuals between age estimates based on tooth wear and diameter of pedicle were not correlated, combining these methods improved the fit slightly. Since tooth wear may differ between areas, the scales presented here may perform less well in other areas, and a calibration for each area is clearly recommended.

Chemical capture and anaesthesia of free-ranging mammals will always involve some risk of mortality even in healthy animals. Deaths may be directly or indirectly attributable to the anaesthetic event itself (e.g. drug overdose, drowning during induction and dart trauma) or may be caused by secondary effects from the capture (e.g. stress, myopathy, trauma or instrumentation with radio-transmitters). In long-term research projects on five major wildlife species in Scandinavia, the capture-related mortality rates (number of captures) were: moose Alces alces 0.7% (N = 2,816), brown bears Ursus arctos 0.9% (N = 1,079), wolverines Gulo gulo 2.8% (N = 461), Eurasian lynx Lynx lynx 3.9% (N = 380), and gray wolves Canis lupus 3.4% (N = 89). We suggest that wildlife professionals should strive for a zero mortality rate but adopt the standard that a mortality rate of > 2% probably should not be accepted in any large mammalian species. This can be achieved by: 1) using an experienced professional capture team, 2) developing and following a capture protocol specific to each species, and 3) requiring that a mortality assessment be undertaken after any capture-related death. This assessment should re-evaluate the capture protocol, including how changes in anaesthetics and methodological approaches could have prevented the mortality.