Trophic Enrichment Factors for Blood Serum in the European Badger (Meles meles)

Ecologists undertaking stable isotopic analyses of animal diets require trophic enrichment factors (TEFs) for the specific animal tissues that they are studying. Such basic data are available for a small number of species, so values from trophically or phylogenetically similar species are often substituted for missing values. By feeding a controlled diet to captive European badgers (Meles meles) we determined TEFs for carbon and nitrogen in blood serum. TEFs for nitrogen and carbon in blood serum were +3.0±0.4‰ and +0.4±0.1‰ respectively. The TEFs for serum in badgers are notably different from those published for the red fox (Vulpes vulpes). There is currently no data for TEFs in the serum of other mustelid species. Our data show that species sharing similar niches (red fox) do not provide adequate proxy values for TEFs of badgers. Our findings emphasise the importance of having species-specific data when undertaking trophic studies using stable isotope analysis.     

Badger Meles meles setts–architecture, internal environment and function

Badger setts vary considerably in size, ranging from simple single-entrance burrows to complex tunnel systems hundreds of metres long with multiple entrances and underground chambers. Data from 19 excavated setts show that main setts are larger than other setts in terms of area and volume, and contain more chambers, nests and latrines; but setts of different sizes and types are built according to the same basic architectural principles. Little is known about the environmental conditions within setts, other than that temperature and humidity are constant in parts of a sett that are at least 7 m from the nearest entrance. Setts are used for breeding and as sleeping places and refuges, but a question remains as to the functional value of large setts. It is suggested that large main setts allow members of a social group to avoid one another underground, especially when breeding. Little is known about the use of other types of sett.     

Fluctuations in the Dutch Badger Meles meles population between 1960 and 1990

The size of the Badger population in the Netherlands is estimated on the basis of sett surveys in 1960, 1970, 1980 and 1990. The numbers of used important setts were 588,640,405 and 606, respectively. So there were strong fluctuations especially due to the drop (-36%) in 1980. In 1990 the number of used important setts nearly returned to the level of 1960. However, there were important regional differences. There was a strong increase in areas with large woodlands, mainly in the central part of the country. In the south, with more traffic, farming and urbanization, the numbers remained 20–30% lower than in 1960, despite the fact that traditionally these were the best Badger areas. Only 25% of the important setts used in 1960 were still in use in 1990. The growth of the number of collapsed or lost setts increased considerably during those 30 years, indicating a rather large sett turnover probably due to disturbance or a related stress factor. Some possible causes of the fluctuations are discussed. It is recommended that a monitoring scheme be carried out every 2 or 3 years in some key areas, in order to get a better idea of the short-term fluctuation range of the population. For one-off, single-observation surveys, a simpler and more-robust sett classification is desirable, based on the number of intact holes, instead of on ‘main setts’.     

The status of the Badger Meles meles (L., 1758) (Carnivora, Mustelidae) in Europe

The Eurasian Badger occurs throughout the Palaearctic, and in all states of Europe west of the border with the former Soviet Union. Within this area it is absent only from the arctic zones, high-altitude areas, and some islands. The Badger is currently a protected species in the UK, the Irish Republic, Spain, Portugal, Italy, Belgium, the Netherlands, Albania, Greece, Estonia, Luxembourg and Hungary, but Luxembourg and Hungary are to reconsider protected status. Elsewhere, the species is either considered as small-game or as a pest, hunting being regulated by closed seasons. At present Finland and Burgenland (Austria) afford protection to breeding females, whilst Bulgaria, Macedonia and the Austrian Bundesländer of Steiermark and Salzburg permit Badger hunting throughout the year. Where the species is protected, provisions usually exist for the removal or culling of ‘pest’ individuals. The official European game-bag currently totals about 118,000 Badgers, but poaching is common, particularly in the UK and Ireland. Published population estimates, coupled with national population minima obtained by extrapolation from game-bag statistics, indicate a minimum European Badger population of 1,220,000; the true figure may exceed this considerably. Badger populations appear to be either stable or increasing throughout much of Europe, although no data are currently available for the populations of Greece, Italy, Spain, Croatia, Bosnia-Hercegovina and Portugal. Badgers are uncommon in the Netherlands, Estonia, Belgium, the Slovak Republic, and possibly Poland. Only the populations of Albania and possibly of some parts of the former Yugoslavia appear to be decreasing. The Dutch population remains at considerable risk, despite modest recent increases. The population status of the endemic sub-species of Crete and Rhodes remain uncertain and require urgent clarification. A series of management recommendations are proposed to improve the status of the Badger in Europe.     

Population Estimation and Trappability of the European Badger (Meles meles): Implications for Tuberculosis Management

Estimates of population size and trappability inform vaccine efficacy modelling and are required for adaptive management during prolonged wildlife vaccination campaigns. We present an analysis of mark-recapture data from a badger vaccine (Bacille Calmette–Guérin) study in Ireland. This study is the largest scale (755 km²) mark-recapture study ever undertaken with this species. The study area was divided into three approximately equal–sized zones, each with similar survey and capture effort. A mean badger population size of 671 (SD: 76) was estimated using a closed-subpopulation model (CSpM) based on data from capturing sessions of the entire area and was consistent with a separate multiplicative model. Minimum number alive estimates calculated from the same data were on average 49–51% smaller than the CSpM estimates, but these are considered severely negatively biased when trappability is low. Population densities derived from the CSpM estimates were 0.82–1.06 badgers km⁻², and broadly consistent with previous reports for an adjacent area. Mean trappability was estimated to be 34–35% per session across the population. By the fifth capture session, 79% of the adult badgers caught had been marked previously. Multivariable modelling suggested significant differences in badger trappability depending on zone, season and age-class. There were more putatively trap-wary badgers identified in the population than trap-happy badgers, but wariness was not related to individual’s sex, zone or season of capture. Live-trapping efficacy can vary significantly amongst sites, seasons, age, or personality, hence monitoring of trappability is recommended as part of an adaptive management regime during large–scale wildlife vaccination programs to counter biases and to improve efficiencies.     

Reproductive Biology Including Evidence for Superfetation in the European Badger Meles meles (Carnivora: Mustelidae)

The reproductive biology of the European badger (Meles meles) is of wide interest because it is one of the few mammal species that show delayed implantation and one of only five which are suggested to show superfetation as a reproductive strategy. This study aimed to describe the reproductive biology of female Irish badgers with a view to increasing our understanding of the process of delayed implantation and superfetation. We carried out a detailed histological examination of the reproductive tract of 264 female badgers taken from sites across 20 of the 26 counties in the Republic of Ireland. The key results show evidence of multiple blastocysts at different stages of development present simultaneously in the same female, supporting the view that superfetation is relatively common in this population of badgers. In addition we present strong evidence that the breeding rate in Irish badgers is limited by failure to conceive, rather than failure at any other stages of the breeding cycle. We show few effects of age on breeding success, suggesting no breeding suppression by adult females in this population. The study sheds new light on this unusual breeding strategy of delayed implantation and superfetation, and highlights a number of significant differences between the reproductive biology of female Irish badgers and those of Great Britain and Swedish populations.     

Climate and the Individual: Inter-Annual Variation in the Autumnal Activity of the European Badger (Meles meles)

We establish intra-individual and inter-annual variability in European badger (Meles meles) autumnal nightly activity in relation to fine-scale climatic variables, using tri-axial accelerometry. This contributes further to understanding of causality in the established interaction between weather conditions and population dynamics in this species. Modelling found that measures of daylight, rain/humidity, and soil temperature were the most supported predictors of ACTIVITY, in both years studied. In 2010, the drier year, the most supported model included the SOLAR*RH interaction, RAIN, and30cmTEMP (w = 0.557), while in 2012, a wetter year, the most supported model included the SOLAR*RH interaction, and the RAIN*10cmTEMP (w = 0.999). ACTIVITY also differed significantly between individuals. In the 2012 autumn study period, badgers with the longest per noctem activity subsequently exhibited higher Body Condition Indices (BCI) when recaptured. In contrast, under drier 2010 conditions, badgers in good BCI engaged in less per noctem activity, while badgers with poor BCI were the most active. When compared on the same calendar dates, to control for night length, duration of mean badger nightly activity was longer (9.5 hrs ±3.3 SE) in 2010 than in 2012 (8.3 hrs ±1.9 SE). In the wetter year, increasing nightly activity was associated with net-positive energetic gains (from BCI), likely due to better foraging conditions. In a drier year, with greater potential for net-negative energy returns, individual nutritional state proved crucial in modifying activity regimes; thus we emphasise how a ‘one size fits all’ approach should not be applied to ecological responses.     

The use of marked bait in studies of the territorial organization of the European Badger (Meles meles)

Bait‐marking is a widely used technique for determining the territorial configuration of social groups of the European Badger (Meles meles). Applications include ecological research and applied wildlife management problems. Bait laced with indigestible plastic pellets is fed to Badger social groups, and the markers are identified in subsequent defecations. Feeding a unique colour and/or shape of pellet to each social group allows the origin of droppings to be assigned. This method is particularly suited to Badgers because they mark their territorial boundaries with communal latrines. In this paper the technique is described in detail for the first time in the scientific literature. Data from sequential visits to latrines during the survey period showed significant short‐term variation in the number of marked droppings counted at individual latrines. This suggests that counting marked droppings may be of limited value in quantifying defecation rates and latrine use. However, counts of droppings at latrines could be useful if repeated over time and/or grouped into broad categories. Bait marking does provide reliable data for the estimation of territorial boundaries between Badger groups, although it is labour intensive and time‐consuming, with the best results obtained by experienced fieldworkers.     

Badger Meles meles diet: a review of literature from the former Soviet Union

We review 69 studies of the diet of Badgers Meles meles L. in the former Soviet Union, using information from 58 Russian-language papers. Animal foods occurred more frequently in the diet than vegetal foods and constituted, on average, 62% of all intake by volume. The most important individual food categories were insects (30% by volume) and small mammals (20% by volume), which appear to be staple foods of Badgers over virtually the whole of the former Soviet Union. Earthworms were mentioned in only a few reports and never exceeded 5% of the diet by volume. Other animal foods included birds, reptiles, amphibians, fish, molluscs and carrion. Fruits were seasonally important in some areas while roots, tubers, bulbs, cereals and nuts were also eaten; but in general, the Soviet literature lacks detailed information about vegetal foods. Many authors comment on seasonal variation in the diet and there was statistically significant seasonal variation in the frequency with which small mammals, reptiles, insects and vegetal foods were eaten. No largescale geographical trends were apparent in the composition of the diet, but foods which were of minor importance overall, such as reptiles, amphibians and molluscs, were sometimes eaten with high frequency in particular localities. The results support the view that Badgers are opportunistic, generalist foragers, with a preference for animal foods when these are available.     

Mediastinal lymphoma in a badger (Meles meles)

A case of mediastinal lymphoma in a free-living, adult male European badger (Meles meles), from Trento Province (northern Italy) is described. A yellow-red mass delimited by a thick fibrous capsule completely occupied the anterior mediastinum. Based on the histologic and immunohistochemical findings, a diagnosis of mediastinal lymphocytic lymphoma was made. Documentation of neoplasms in free-living species is important for comparison with domestic animals and humans and may give insight into epidemiology of these diseases. To the authors' knowledge, this is the first report of a mediastinal lymphoma in a badger.     

Digging Behaviour while Foraging by the European Badger,Meles meles,in a Mediterranean Habitat

Digging behaviour while foraging by the European badger (Meles meles) was studied in the Maremma Natural Park, central Italy, during late winter and spring of 1984 and 1985. Badgers digging for Lamellicornia larvae were successful in approximately 77% of the observed digging attempts. Digging success was similar among individuals and months and was positively correlated with the depth of the hole. A change of position while digging was associated with successful digging. Badgers always started their digging activity using only a foreleg at a constant rate and at a later stage used both forelegs alternately at a higher rate. The adoption of such technique is regarded as adaptive since it maximizes the chance of capturing the prey while reducing the energy expenditure due to digging. The reduced availability of those resources to be collected on the ground surface during late winter and spring is suggested as the possible cause of the energetically expensive digging behaviour.     

Lunar-related reproductive behaviour in the badger (Meles meles)

Cyclicity in behaviours, including reproduction, in relation to the lunar cycle is widely documented in some phyla, but weak or unknown in Class Mammalia. In this paper we present long-term video surveillance data of wild Eurasian badgers Meles meles, which reveal a strong correlation between reproductive behaviour and the lunar cycle. Squat marking and raised-leg urination, which increase in frequency at times of reproductive activity, showed maxima around day 22 of the lunar cycle (i.e. new moon). These findings were supported by observations of matings, together with published records, which showed significantly higher occurrence in the lunar dark phase (last quarter to first quarter). We propose that the lunar cycle has the potential to act as a regulator of the reproductive cycle in the badger.