Seasonal and spatial pattern of shelter use by badgers<Emphasis Type="Italic">Meles meles</Emphasis> in Białowieża Primeval Forest (Poland)

In 1997–2001, we investigated the use of day-time shelters by radio-collared badgersMeles meles (Linnaeus, 1758) in the Białowieża Primeval Forest, eastern Poland. Each social group of badgers utilised, on average, 9 different shelters per territory (range: 4–20). The main setts, occupied for breeding and winter sleep, were also most frequently used for day-time rest throughout the year (73% of days). Badgers living in the pristine oldgrowth stands utilised larger number of shelters and spent more days in hollow trees (mainly limeTilia cordata), compared to badgers inhabiting younger secondary tree stands. Number of shelters used by individuals varied between seasons and depended on sex and age of animals. In summer, badgers used more shelters than in spring and autumn. In winter, they stayed in their main setts only. Adult males occupied more shelters and spent fewer days in the main sett than other badgers. In spring, females rearing young used only the main setts. The average underground space used by badgers within the main sett was 128 m². It was largest in summer and smallest in winter, and also varied between males and females. We proposed that, in a low-density population, badgers used several setts and other daily shelters to reduce energy expenditure when exploring their large territories and foraging. Furthermore, setts may play a role of marking sites. Analysis of the biogeographical pattern of sett use by European badgers showed that the number of setts used by social groups increased with increasing territory size, whereas the density of setts (n setts/km²) was negatively correlated with territory size. We proposed that different factors could shape the utilisation of setts by badgers in low- and high-density populations.     

Internal structure and contents of three badger (Meles meles) setts

Three badger ( Meles meles L.) setts in the south of England, which formed a single sett complex belonging to one social group of badgers, were excavated prior to being destroyed by construction of a new road. Setts 1 and 2, classified as annexes, were excavated completely; sett 3, classified as a main sett, was only excavated partially, but its total size was estimated from the excavated portion. The setts consisted of tunnels totalling 16 m, 140 m and 879 m, respectively; contained one, nine and 50 chambers; and had five, 42 and 178 entrances. The total volume of the three setts was about 45 m³, and their construction was estimated to have required the removal of about 70 tonnes of soil. In the two smaller setts tunnels ran on a single level with an average depth of 99 cm; in the larger sett they ran on two levels with modal depths of 50 cm and 110–120 cm, respectively. All three setts contained bedding material (dry grass and plastic bags) but only the main sett contained latrines. None of the setts contained badger bones and the interiors of all three setts were remarkably clean and orderly. We discuss hypotheses as to why badgers sometimes continue to extend even large well-established setts but conclude that the survival value of very large setts remains problematical.     

Spatial Targeting for Bovine Tuberculosis Control: Can the Locations of Infected Cattle Be Used to Find Infected Badgers?

Bovine tuberculosis is a disease of historical importance to human health in the UK that remains a major animal health and economic issue. Control of the disease in cattle is complicated by the presence of a reservoir species, the Eurasian badger. In spite of uncertainty in the degree to which cattle disease results from transmission from badgers, and opposition from environmental groups, culling of badgers has been licenced in two large areas in England. Methods to limit culls to smaller areas that target badgers infected with TB whilst minimising the number of uninfected badgers culled is therefore of considerable interest. Here, we use historical data from a large-scale field trial of badger culling to assess two alternative hypothetical methods of targeting TB-infected badgers based on the distribution of cattle TB incidents: (i) a simple circular ‘ring cull’; and (ii) geographic profiling, a novel technique for spatial targeting of infectious disease control that predicts the locations of sources of infection based on the distribution of linked cases. Our results showed that both methods required coverage of very large areas to ensure a substantial proportion of infected badgers were removed, and would result in many uninfected badgers being culled. Geographic profiling, which accounts for clustering of infections in badger and cattle populations, produced a small but non-significant increase in the proportion of setts with TB-infected compared to uninfected badgers included in a cull. It also provided no overall improvement at targeting setts with infected badgers compared to the ring cull. Cattle TB incidents in this study were therefore insufficiently clustered around TB-infected badger setts to design an efficient spatially targeted cull; and this analysis provided no evidence to support a move towards spatially targeted badger culling policies for bovine TB control.     

The role of setts in badger (Meles meles) group size, breeding success and status of TB (Mycobacterium bovis)

This paper examines the relationship between the number of occupied setts in a badger social group territory and badger group size, breeding success, and status of infection with Mycobacterium bovis (TB). The data used were from a long-term epidemiological and ecological study of a high-density population of badgers Meles meles in south-west England. The number of occupied setts in a social group was significantly and positively related to the number of badgers caught in the social group, so that as a social group increases in size, badgers occupy more of the available setts. This relationship remained significant when numbers of adults, adult males and adult females were examined. The number of breeding females, number of cubs and sex ratio was not related to the number of occupied setts in a social group. It is possible that the advantages to breeding females of a larger number of setts available to breed in might be outweighed by the increased aggression found in larger groups. The TB score for prevalence and for incidence of social groups was significantly and positively related to the number of occupied setts in a social group, such that the more occupied setts there were in a territory, the higher the TB index of the group. Possibly the setts themselves contribute to the persistence of TB within social groups, or badgers infected with TB might show a difference in behaviour from uninfected badgers resulting in their increased use of outlying setts.     

狗獾夜间活动节律是受人类活动影响而形成的吗?基于青海湖地区的研究实例

青海湖地区是目前已知的狗獾分布海拔最高点。为了解狗獾在青藏高原严酷生态环境下的生活史特点, 并验证是否人类干扰造成了狗獾夜行性的假说, 我们利用红外相机技术, 结合无线电遥测和野外调查研究了青海湖湖东地区亚洲狗獾(Meles leucurus)的种群密度、洞穴口的行为及活动节律。结果表明: (1)研究地区狗獾的平均种群密度为1.2 ± 0.6只/km², 其分布受食物丰富度的影响; (2)狗獾基本在夜间活动, 出洞时间集中在20:00-23:00之间, 而回洞时间则集中在清晨4:00-7:00之间, 23:00-4:00之间是狗獾的活动高峰; (3)狗獾离洞前行为主要是警戒行为, 回洞穴时的行为主要是嬉戏行为, 其他行为较少见, 表达具有特定的时间性; (4)人类活动对于狗獾活动没有显著性影响(P < 0.05)。     

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.     

Distribution and population density of badgers Meles meles in Luxembourg

1. The distribution and density of Eurasian badgers Meles meles in Luxembourg was estimated by gathering information about the location of badger setts with a questionnaire survey, by visiting 708 setts in order to classify them as ‘main setts’ or ‘outliers’, and by estimating social group size by directly counting emerging badgers. 2. Badgers were found to be widely distributed in Luxembourg, with a minimum main sett density of 0.17 setts/km². Setts were sited preferentially in forest habitat. The mean minimum group size was 4.6 badgers. 3. The Luxembourg badger population was conservatively estimated to contain at least 2010 adult and young badgers (95% CI 1674–2347) in spring 2002, equivalent to a density of 0.78 adult and young badgers/km² (95% CI 0.65–0.91). This is moderate compared to most of continental Europe.     

Escape Tactics and Alarm Responses in Badgers Meles meles: A Field Experiment

A typical badger (Meles meles) territory contains a primary burrow or 'main sett' plus several secondary burrows or 'outlier setts'. The main aim of our study was to test the hypothesis that outlier setts are used as emergency refuges, by subjecting foraging radio-collared badgers to three levels of experimental disturbance (low, moderate and high). In addition, we recorded the occurrence of potential alarm signals. With low-level disturbance, badgers usually returned to the main sett even when this was further away than the nearest outlier sett; with high-level disturbance they always took refuge in the nearest outlier; and with moderate-level disturbance they showed no clear preference. We conclude that outlier setts do act as emergency refuges, but only when an animal is badly frightened. Possible alarm signals (pilo-erection, head-flagging, snorting and growling) occurred mainly during moderate or high-level disturbance but even then they were relatively infrequent. Signals were no more likely to be emitted when conspecifics were near by than when the signaller was alone, and when conspecifics were present they rarely reacted either to the flight of the disturbed animal or to any signals that it emitted. We conclude that such alarm signals as do occur constitute threats directed towards the predator rather than warnings for the benefit of conspecifics.     

Use of human buildings by Eurasian badgers in the Moravskoslezské Beskydy Mountains,Czech Republic

An inspection of human buildings used by Eurasian badgersMeles meles (Linnaeus, 1758) in 28 sites in the Moravskoslezské Beskydy Mountains, Czech Republic, was carried out in 2001. The buildings inhabited or visited by badgers were as follows: wooden barns (18 cases), masonry buildings used for residential purposes (4), abandoned buildings (1), wooden sheds (2), wooden beehouses (2) and a non-residential part of a house (1). In three sites, female badgers with their cubs inhabited buildings. Badgers use the buildings more frequently in winter than in summer. Use of human buildings and the occurrence of badgers in setts in the wild in these mountains was observed in detail on a study area of 950 ha around the village of Lubno. In total, 12 setts were discovered. Eight of them were in the wild: two setts were located closer than 50 m, five between 100 m and 300 m, and one 700 m from human buildings. In four sites badgers inhabited human buildings.     

The distribution of Eurasian badger, Meles meles, setts in a high-density area: field observations contradict the sett dispersion hypothesis

Are setts significant determinants of badger socio‐spatial organisation, and do suitable sett sites represent a limited resource, potentially affecting badger distributions? The factors determining diurnal resting den, or sett, location and selection by Eurasian badgers Meles meles L. were investigated in Wytham Woods, Oxfordshire. 279 sett sites were located. The habitat parameters that were associated with the siting of these setts were analysed and associations were sought between sett location and character and the body condition and body weight of resident badgers Habitat characteristics in the vicinity of setts were significantly different from randomly selected points. Badgers preferentially selected sites with sandy, well‐drained soils, situated on NW‐facing, convex and moderately inclined slopes at moderate altitude. There was no evidence that sett morphology (number of entrances, sett area, number of hinterland latrines) was affected by the surrounding sett site habitat characteristics. Mean body weight was significantly higher for badgers occupying territories with setts in sandy soils, situated on NW‐facing slopes, than in territories with less optimal sett characteristics. Contrary to the hypothesis that the availability of sett sites was limiting, and therefore that sett dispersion dictates the spatial and social organisation of their populations, the badgers were clearly able to excavate new setts. On our measures, these new setts were not inferior to old established ones, despite occupying subsequently exploited sites; the badgers utilising these new setts had neither lighter body weights nor poorer body condition scores. During the period of our study badgers have manifestly been able to dig numerous new setts; as satisfactory sites still remain available, this indicates that suitable sett sites have not yet become a limiting resource. There was no relationship between sett age and the characteristics of the site in which it was dug, as suitable sites were not limiting. Significantly, population expansion during the decade 1987–1997 was not constrained by lack of setts, rather the main proliferation in setts occurred after the population size had peaked in 1996. Some implications for the management and conservation of the Eurasian badger are considered.     

Urban badger setts: characteristics, patterns of use and management implications

Damage caused by badger setts is an important source of human–carnivore conflict in urban areas of the UK, yet little is known about the spatial distribution of urban badger setts or their pattern of occupation. We compared the density, spatial distribution and size of setts in four urban and two rural study areas in the UK and assessed the applicability to urban systems of distinguishing between 'main' and 'outlier' setts. In addition, we used radio-telemetry to investigate diurnal patterns of sett use in one urban area (Brighton). It was possible to distinguish between main and outlier setts in urban environments, and local sett densities were comparable in urban and rural areas. However, urban badgers used substantially fewer setts than did a nearby rural population, and they spent a smaller proportion of days in outlier setts. Social groups with larger ranges had more setts available to them and, within groups, individuals with larger ranges used more setts. Outliers appeared to serve multiple functions, including allowing efficient and safe travel to important parts of the home range. We conclude that sett densities can be high in urban habitats, suggesting significant potential for sett-related problems to arise. The fact that urban main setts can be distinguished from outliers enables management actions to be tailored accordingly. In particular, because main setts seem to represent a particularly valuable resource to urban badgers, alternatives to the closure of problem main setts need to be considered.     

Evaluating seasonal bait delivery to badgers using rhodamine B

In the UK and Ireland, research on the control of bovine tuberculosis in badgers includes the development of a palatable bait for oral delivery of a vaccine and a means of its deployment in the field. In the present study, we carried out field deployment of bait according to the established method of bait marking in early spring and early summer to compare the effects of seasonality on bait uptake rates. All baits contained rhodamine B (RhB) which was subsequently detected in the hair and whiskers of captured badgers. During the 8 days of bait feeding at 14 badger setts, 99% of baits deployed in spring, and 100% of those deployed in summer were removed. The presence of RhB in captured badgers indicated high rates of uptake amongst adult badgers in spring (93%) and summer (98%). Only cubs captured in summer showed evidence of having taken bait (91%). Between 67% and 100% of each social group was estimated to have taken bait. The detection of RhB in 96% of badgers captured at outlier setts, where bait was not fed, suggested that deployment at main setts alone may be sufficient to target a relatively high proportion of the badger population. The number of baits deployed per marked badger suggested that a similar level of uptake might be achievable using fewer baits. The results clearly demonstrate the potential value of the bait-marking methodology for delivering vaccine baits to badgers during spring and summer, but that deployment in early summer is necessary to target cubs.     

Interspecific visitation of cattle and badgers to fomites: A transmission risk for bovine tuberculosis?

In Great Britain and Ireland, badgers (Meles meles) are a wildlife reservoir of Mycobacterium bovis and implicated in bovine tuberculosis transmission to domestic cattle. The route of disease transmission is unknown with direct, so‐called “nose‐to‐nose,” contact between hosts being extremely rare. Camera traps were deployed for 64,464 hr on 34 farms to quantify cattle and badger visitation rates in space and time at six farm locations. Badger presence never coincided with cattle presence at the same time, with badger and cattle detection at the same location but at different times being negatively correlated. Badgers were never recorded within farmyards during the present study. Badgers utilized cattle water troughs in fields, but detections were infrequent (equivalent to one badger observed drinking every 87 days). Cattle presence at badger‐associated locations, for example, setts and latrines, were three times more frequent than badger presence at cattle‐associated locations, for example, water troughs. Preventing cattle access to badger setts and latrines and restricting badger access to cattle water troughs may potentially reduce interspecific bTB transmission through reduced indirect contact.     

Assessing spatiotemporal associations in the occurrence of badger–human conflict in England

Examples from a variety of taxa demonstrate that under certain circumstances, the exclusion or translocation of ‘problem’ animals is ineffective in resolving human–wildlife conflicts and may even elicit new problems elsewhere. Damage caused by badger setts (burrows) is an important source of human–wildlife conflict in the UK and is commonly managed by excluding badgers from all or part of problem setts. We used records of licences issued for the management of such problems and a novel statistical approach to assess spatiotemporal associations between problem cases in England from 2002 to 2005. We predicted that management at urban badgers' setts, and particularly exclusion of badgers from urban main setts, would give rise to subsequent problems at focal setts and in neighbouring areas. Frequencies of problems occurring at individual setts were similar in urban and rural areas. In areas neighbouring setts subjected to management action, the background frequency of problems was higher in urban than in rural areas, reflecting the occurrence of problems at a higher proportion of urban setts. The frequency of new cases arising at or in the vicinity of managed setts within a critical time period after management action was not significantly different from the background frequency of problems for any combination of land use, sett type and management approach. This finding suggests that the measures currently employed for managing problem setts do not importantly increase the likelihood of problems reoccurring in the same location or emerging nearby.     

Resource dispersion and badger population density in Mediterranean woodlands: is food,water or geology the limiting factor?

Eurasian badgers, Meles meles, in Mediterranean cork‐oak woodlands live in small groups within territories that embrace a mosaic of habitats where several setts (dens) are scattered. Assuming that their population density was related to home range sizes and that this in turn was influenced by food and water availability and the existence of substrate suitable for sett construction, we explored the relationship between these parameters. Two biotopes were predominantly important in providing food security to badgers in the ‘Grândola’ mountain study area: olive groves and orchards or vegetable gardens. Analysis of the mean total area of these two habitats in the ranges of radio‐tracked badgers permitted us to extrapolate to an estimate that the 66 km² encompassed eleven areas with the capacity to support badger groups each composed by 6–8 individuals. Since only three groups populated the area we concluded that food availability was not limiting badger density. Sites with surface water in summer (the dry season) seem sufficient to support more badger groups than existed, leading us to believe that this factor was also not limiting badger density. Simultaneously, using a logistic regression model and the biophysical characteristics of sett sites as explanatory variables, four predictor variables determined sett location: the existence of a geological fault/discontinuity, ridges, valleys and the distance to abandoned farm houses, of which the former had the higher odds ratio, being thus the best sett location predictor. Indeed, 56% of the areas predicted with >80% confidence to contain a badger sett were encompassed within a known home range. Therefore, our results suggest that, in Mediterranean cork oak woodlands in SW Portugal, the main factor limiting badger's density is the availability of suitable sites for setts. However, in areas where suitable sites for burrows existed, but food patches were absent, badgers were not found. This could indicate that the presence of both factors was necessary for badgers, although in this area sites suitable for digging setts appeared to be the primary limiting factor.     

The density and distribution of badger setts in the Sudety Mountains,Poland

The density and distribution of badgerMeles meles (Linnaeus, 1758) setts was estimated by questionnaires and field studies, carried out in the Sudety Mountains between 1995–2002. The questionnaire referred to the whole territory of Polish Sudety Mts, while field studies were conducted in four different habitat types: low mountains with a mosaic farm-forest landscape, highly industrialised hilly areas, high mountain ranges of natural character and high mountain ranges of severe microclimate and heavily destroyed tree stands. On the basis of both questionnaires and field surveys, a total of 378 badger setts, classified according to their size and status, were identified. Among these, 119 (31.5%) were situated on three areas, while in the fourth area we did not find any badger setts. According to their size and traces of intensive occupation, 54 setts were regarded as main badger setts. The mean density of main setts on three areas was much the same and amounted to 0.05–0.07/km² of their total surface, despite differences in their natural environment and agricultural or industrial changes in landscapes. In the Sudety Mts badgers selected settlements in forest habitats, bordering rich in food open areas. The density of main setts in forest areas ranged from 0.12 to 0.33/km² depending on the proportion of forest, type and age of tree stands and size of forest complexes. The mean distance of main setts from open areas ranged from 209 to 280 m. The mean nearest neighbour distance (NND) between main setts ranged from 2.85 to 3.75 km. The home range size estimated for a social group varied from 7.9 to 13.6 km². The highest occupied setts of our study were found on the ?nie?nik Massif, at an altitude of 700 m a.s.l.     

Long-lasting systemic bait markers for Eurasian badgers

This study was carried out to assess whether Rhodamine B, ethyl-iophenoxic acid (EtIPA), and propyl-iophenoxic acid (PrIPA) can be used as long-lasting systemic bait markers for free-living badgers (Meles meles). Between June and November 2003, these chemicals were incorporated into bait distributed around badger setts. Serum, hair, and whiskers from individually marked badgers were collected in the following 4 to 24 wk. Rhodamine B was detectable as fluorescent bands up to 24 wk after ingestion of the bait. Individual badgers were found positive for EtIPA and PrIPA up to 20 wk and 18 wk after exposure, respectively. This study indicates that Rhodamine B, PrIPA, and EtIPA could be used as long-lasting markers for badgers.     

Winter hibernation and body temperature fluctuation in the Japanese badger, Meles meles anakuma

This study examined seasonal changes in body weight, hibernation period, and body temperature of the Japanese badger (Meles meles anakuma) from 1997 to 2001. Adult badgers showed seasonal changes in body weight. Between mid-December and February, badger activity almost ceased, as the animals remained in their setts most of the time. Adult male badgers were solitary hibernators; adult females hibernated either alone or with their cubs and/or yearlings. The total hibernation period of Japanese badgers ranged from 42 to 80 days, with a mean length of 60.1 days. Japanese badgers did not always spend the winters in the same sett, although they seldom changed setts during hibernation. I equipped a male cub with an intraperitoneally implanted data logger to record its body temperature between November and April, while the cub hibernated with its mother. Over the winter, the body weight of the cub decreased from 5.3 kg to 3.6 kg, a weight loss of 32.1%, and its body temperature ranged from 32.0 to 39.8 degrees C. The mean monthly body temperature was 35.1 degrees C in December, 34.8 degrees C in January, 35.9 degrees C in February, 37.1 degrees C in March, and 37.4 degrees C in April, so the monthly decrease in body temperature of this cub was not great. The results indicate that during hibernation, when body temperature is low, there is likely considerable economy of energy and a reduced demand for adipose reserves.     

Environmental determinants of the <Emphasis Type="Italic">Mycobacterium bovis</Emphasis> concomitant infection in cattle and badgers in France

Landscape epidemiology analyses how environmental characteristics influence pathogen transmission between hosts of one or several species, by inducing constraints on space use by hosts, and/or on pathogen survival in the environment. Here, we analysed how environmental variables could be associated with the Mycobacterium bovis concomitant infection in both cattle and badgers, in an area of south-western France. We defined circular spatial units (500 and 1000 m radiuses) centred on 113 setts of trapped badgers and including cattle pastures. The characteristics of spatial units where only one species had been found infected were compared with the ones where both cattle and badgers had been found infected. A multivariate logistic model was used to analyse the association between concomitant infection in both species and three groups of variables describing landscape, animal population and terrain features of spatial units. The terrain ruggedness index of pastures and the percentage of sand in their soil were positively associated with the odds of concomitant infection in cattle and badgers in the spatial units. The number of neighbouring badger groups was negatively associated with the odds of concomitant infection (spatial units of 1000 m radius), whereas the number of crop parcels was positively associated with the odds of concomitant infection (spatial units of 500 m radius). These results suggest that terrain features, badger population structure and food availability may influence the spread of M. bovis infection between badgers and cattle, leading to concomitant infection of both species.