Interspecific den sharing: a study on European badger setts using camera traps

The eastern cottontail Sylvilagus floridanus is a native American lagomorph. Within the genus Sylvilagus, the eastern cottontail is the species with the widest distribution. From 1950s, the species was introduced to several European countries. A rapid territorial expansion of the introduced eastern cottontails has been observed in many areas of Italy. The eastern cottontail has been demonstrated to play a main role as carrier of exotic parasites. To date, three nematode species, exotic in Italian ecosystems, have been reported from introduced S. floridanus. However, its parasite fauna biodiversity is richer in native populations of the American continent. The aim of this work was to further investigate the gastrointestinal parasites of S. floridanus, to evaluate the potential presence of other exotic species. During 2010, 101 hosts were examined, and three nematodes were collected from their digestive tract. Two parasite species (Obeliscoides cuniculi, Trichostrongylus calcaratus) were already reported in Italy; the isolation of Trichostrongylus affinis is instead the first report of this nematode in Italy and in Europe as a whole. This study wants to highlight the great risks related to the introduction of allochthonous species. The impact of the invasion by alien animal species may be particularly severe for public and animal health, due to the potential introduction of new pathogens. The good number of exotic parasites found in introduced eastern cottontails, together with the few sanitary surveys carried out, suggests that an epidemiological survey, with specimens from multiple localities on a wider geographic range, could lead to interesting findings on parasites of native and alien lagomorphs in Europe.

For hundreds of years naturalists have observed that some mammalian species show dramatic changes In numbers of individuals present in populations over a period of years. The term "population cycles" has been used to characterize such changes, if they are periodic. Classic examples of cyclic species are found mostly within the lemmings and voles (Microtinae) and among the rabbits and hares (Leporidae). Many attempts to explain population phenomena have been made. Such factors as sunspots (Elton, 1924), atmospheric ozone cycles (Rowan, 1954), predation (Elton, 1942) and disease (Chitty, 1950) have all been postulated as causative factors underlying population fluctuations. Recently the adrenopituitary system was indicated as a causative factor in the cyclic fluctuations o f mammals (Christian, 1980}. The literature since 1960 concerning the adrenopituitary system in relation to population fluctuations is legion, yet Christian's statement in 1950 that cyclical phenomena remain unexplained is still largely true. In addition to variations in adrenal morphology related to population factors, there are observations of sexual and seasonal variations and dimorphisms in the adrenal glands of a variety of mammals, domestic and wild (McKeever, 1959). The implication of the adrenal glands in population fluctuations coupled with the possibility of seasonal and sexual dimorphisms in the adrenal glands of rabbits has precipitated this study. The cottontail rabbit (Sylvilagus floridanus) is exceptionally suited to such a study. There is a well defined reproductive cycle and high reproductive potential (Schwartz, 1959; Conaway, Wight and Sadler, 1963) which in turn reflects at leant a seasonal abundance of rabbits. In addition, classic population cycles have been reported in this species (Wight, 1959). The cottontail is easily collected in large enough numbers to provide for statistically significant geographical and temporal sequences. This study has revolved around the following parameters of investigation. 1. Age and sex variation in adrenal histology and histochemistry. 2. Seasonal variations in adrenal histology and histochemistry. 3. Reproductive variation in adrenal histology and histochemistry. 4. Variation in the adrenals due to mortality or population fluctuation.

Predictive models of the spatial distribution and abundance of species based on habitat characteristics are finding increasing use in management and conservation. The European badger attracts interest as a model species both for conservation reasons and because of the important role the species is playing in understanding carnivore sociality. We developed a statistical habitat model based on presence/absence data on badger setts. To maximise the utility of the model in management, we limited the choice of model variables to those that had a clear basis in badger ecology and that could be obtained on a nation-wide digital format. We extrapolated the habitat model to a region in Denmark and developed a threshold-independent sett distribution algorithm to estimate sett densities. The habitat model was simpler than previously published models of badger sett habitat selection, but nevertheless had a predictive ability in excess of 80% judged against independent data. The sett distribution algorithm was able to simultaneously reproduce several observed patterns of sett density and distribution over the probability gradient. It thus represents a significant improvement over threshold-dependent methods used to discriminate between suitable and unsuitable habitat predicted by presence/absence regression models. Our approach demonstrates that a model of badger sett habitat suitability with high predictive power can be obtained using easily accessible map-variables and presence/absence data. This is a prerequisite for using habitat models as predictive tools over large areas. The use of a simple sett distribution algorithm circumvents the common problem of subjectively fixing a threshold to discriminate between suitable and unsuitable habitat. In conjunction the models presented here constitute an important contribution to the management of the badger in Denmark and, upon further validation, possibly to similar regions in Northern Europe.

Simple SummaryPredator-prey relationships and competition shape interspecific coexistence in wildlife communities. So far, most published studies have focused on large carnivores and their prey, whereas little is known about medium and small-sized mammal communities. The European brown hare Lepus europaeus is a widespread species in Europe and is part of the diet of many birds of prey and mammalian carnivores of all sizes. Furthermore, competition with other herbivorous mammals at feeding sites has also been suggested. In an area in Central Italy, we have assessed spatiotemporal overlap among brown hare and its potential predators (red fox Vulpes vulpes, pine marten Martes martes, domestic cat Felis catus, and domestic dog Canis familiaris) and a competitor (roe deer Capreolus capreolus). We showed that, outside a fenced area excluding predators and competitors, brown hares become more nocturnal and more active on dark nights to limit encounters with predators, and that they adopt spatial partitioning to avoid competitors, as expected by ecological theory.Analysis of spatiotemporal partitioning is pivotal to shed light on interspecific coexistence. Most research effort has involved large-sized carnivores and their prey, whereas little attention has been devoted to lagomorphs. We assessed spatiotemporal overlap among the European brown hare Lepus europaeus and its potential competitors and predators through camera-trapping in an area in Central Italy. We estimated the interspecific patterns of the spatiotemporal activity rhythms of brown hares, its potential predators (the red fox Vulpes vulpes, the pine marten Martes martes, the domestic cat Felis catus, and the domestic dog Canis familiaris), and a competitor, the roe deer Capreolus capreolus. Brown hare activity was studied in natural conditions as well as in a fenced area that excluded terrestrial predators and competitors. Free-ranging hares developed a more nocturnal behavior to avoid diurnal predators (i.e., domestic carnivores and martens). Although high temporal overlap was observed between free-ranging brown hares and both red foxes (82%) and roe deer (81%), hares avoided fox by being more active on darkest nights, as well as avoided roe deer through spatial partitioning. We suggest that hares may adapt their spatiotemporal behavior to avoid potential predators and competitors.

In mammals, ecological interactions are difficult to observe directly, so they are usually inferred from co‐occurrence data. Direct interpretation of co‐occurrence patterns can be complicated since they may be the result of different processes such as habitat selection. We propose a logical framework along with multispecies occupancy models, to distinguish which process or interaction of processes gives rise to co‐occurrence patterns. We also used temporal kernel density estimates to explore the overlap in diel activity patterns, and ecological knowledge of the species as a complement to explain the drivers that generate co‐occurrence. To test our framework, we analyzed three mammal species: the bobcat (Lynx rufus), the gray fox (Urocyon cinereoargenteus), and their potential prey, the eastern cottontail rabbit (Sylvilagus floridanus), in a tropical dry habitat at Tehuacán‐Cuicatlán Biosphere Reserve, Mexico. Data were collected across 67 camera trap stations that operated from February to August 2018. The best‐fitted model described the spatial interaction between U. cinereoargenteus and L. rufus with S. floridanus; in both cases, the occupancy probability of the predatory species was higher in the presence of their prey than in their absence. Additionally, the three species presented a high overlap in their temporal activity patterns. Based on the knowledge of the species' ecology and our results, we identified that trophic interactions could be an important process shaping the co‐occurrence patterns of these species. In short, our framework highlights that it is possible to discern among the processes that influence the co‐occurrence patterns for species with well‐defined ecological roles, such as in our study system.

Cottontail rabbits represent the first wild species of the order of lagomorphs whose hearing abilities have been determined. Cottontails, Sylvilagus floridanus, evolved in the New World, but have spread worldwide. Their hearing was tested behaviorally using a conditioned-avoidance procedure. At a level of 60dB SPL, their hearing ranged from 300Hz to 32kHz, a span of 7.5octaves. Mammalian low-frequency hearing is bimodally distributed and Cottontail rabbits fall into the group that hears below 400Hz. However, their 300-Hz limit puts them near the gap that separates the two populations. The minimum audible angle of cottontails is 27.6°, making them less acute than most other species of mammals. Their large sound-localization threshold is consistent with the observation that mammals with broad fields of best vision require less acuity to direct their eyes to the sources of sound.

We tested for dietary choices of foods varying in nutrient composition by cottontail rabbits on two college campuses in midwestern USA. We quantified choices among pellets of varying nutritional quality at artificial food patches. Dietary choices differed between seasons and locations. Spring giving-up densities (GUDs: food left behind) did not show differences in food choices and were lower than summer GUDs. In Appleton, the cottontails favoured both high protein and fibre pellets, whereas the medium protein and fibre pellets were favoured in Chicago. The cottontails maintained their choice of high protein, high fibre pellets at three spatial scales. The cottontails varied food intake to balance their protein, salt and fibre needs at different times and locations. Studying dietary choices and the effect of resource quality on foraging responses by urban wildlife provides a useful tool to study ecological interactions and can help minimize damage in urban environments such as parks.

The diet of the lesser spotted eagle (Clanga pomarina) was studied in the area that is now the Amvrakikos Wetlands National Park during the Spring periods of 2000 and 2002 by analysis of pellets and prey remains found at two active nest sites, in two different territories. Among 155 prey items collected, in terms of biomass, the diet was 43% reptiles, 30% birds, 24% mammals, 3% amphibians and 1% arthropods. The most important prey taxa were brown rat (Rattus norvegicus) at 19%, water snakes (Natrix spp.) at 11% and moorhen (Gallinula chloropus) at 11% composition. Despite a wide availability of semi-natural and agricultural habitats around the immediate nesting areas, the species seems to have invested in foraging largely on water-dependent animals. The species maintained only one or a maximum of two pairs in the wider region during the study, this being at the southwestern margin of its global breeding range. Conservation insights and recommendations are presented.

Some 5000 Barn owl pellets, collected from sites in East Norfolk during the past decade, have been examined. The most important prey species, by weight, were the Field vole (Microtus agrestis) 52%, the Brown rat (Rattus norvegicus) 17%, and the Common shrew (Sorex araneus) 12%. The prey varies over different habitats; Wood mice (Apodemus sylvaticus) and Bank vole (Clethrionomys glareolus) forming a higher proportion in localities with hedges, scrub and woodland than in open grasslands. These results are comparable with those of other recent work. However, when compared with studies conducted over 30 years ago, it would appear that the Field vole now constitutes a higher proportion, and the Brown rat a lower proportion, of the prey taken.

Biological invasions are one of the main components of human-caused global change and their negative impact on invaded ecosystems have long been recognized. Invasive mammals, in particular, can threaten native biodiversity and cause economic impacts in the region where they are introduced, often through a wide range of conflicts with humans. Although the wild boar, Sus scrofa, is considered by the IUCN as one of the 100 invasive species most damaging to biodiversity in the world, in Argentina there have only been a few studies focused on its ecology with most of them conducted in protected areas. In this study, we evaluated the effect of several factors related with human disturbance, landscape composition, degree of fragmentation and the presence of a potential competitor and a predator on the habitat use of wild boar using data from camera traps and site-occupancy modeling. Additionally, we described the daily activity pattern of the species and we studied the level of overlap with both a potential competitor and a predator. The sampling effort totaled 7,054 camera trap days. Farm density, proportion of shrubland and proportion of grassland with bushes were the detection variables included in the most supported model whereas proportion of grassland and capture rate of the Pampas fox Lycalopex gymnocercus were the occupancy variables included in the most supported model. However, the proportion of grassland was the only variable that showed statistically significant support in the averaged model, indicating that habitat use of wild boar in this area was significantly negatively affected by the level of grass cover. Wild boars were mostly nocturnal, with more activity between 21:00 and 3:00 and a peak around midnight. Wild boars showed a high level of overlap with the activity pattern of the Pampas fox and a low overlap with the activity pattern of the puma Puma concolor. Despite wild boar being introduced in Argentina a few decades ago, this study is the first landscape-scale research carried out in an agricultural landscape in Argentina and the first one based on camera-trapping data. Our study contributes valuable information that could be used to design strategies to reduce wild boar population or to minimize the damage caused by this invasive species in Argentina.

In Europe, invasive alien mammals are often controlled by voluntary hunters. However, no research investigated if control operations could be entirely performed by volunteers, nor how to maximize their recruitment. By using the Eastern cottontail (Sylvilagus floridanus) in Central Italy as a case study, we carried out a factorial survey over a sample of hunters (n = 134), exploring which attributes influenced their hypothetical participation to control programs for cottontails. Hunters were more willing to engage in control schemes if these included shooting sessions, not trapping. Moreover, they would have been more prone to control cottontails if they had received evidence of cottontail impacts over native wildlife or local crops. The geographical scale of the management plan and its goals and required efforts did not have any effect over the evaluation of management scenarios. As many European control schemes for invasive alien mammals are carried out in contexts where shooting is unfeasible, like urbanized neighborhoods, our findings show that agencies cannot entirely rely on volunteers and they should complement their limitations with full-time staff. Moreover, if wildlife agencies want to recruit volunteers, they should provide adequate information about the environmental and social impacts of invasive alien mammals.

Left eye lenses of sharp-tailed grouse (Pedioecetes phasianellus) bagged in South Dakota were oven-dried and weighed to determine variations between sexes and within age-classes. The mean difference in lens weight was highly significant for 162 juvenile males and 190 juvenile females, 51 adult males and 83 adult females, juvenile males and adult females, and all juveniles tested against all adults. Males had lens weights exceeding those of females; adults had lens weights exceeding those of juveniles. Although considerable overlap exists between lens weights of juveniles and adults, an adjustment can be applied to separate age-classes in a sample of unknown age. Apparently little, if any, increase in lens weight occurs after the first year. Eyeballs were collected from sharp-tailed grouse to determine whether juveniles and adults could be separated on the basis of lens weight, and whether adult lens weights would show groupings indicative of yearly age-classes. Lens weights have been shown to be reliable indicators of age for several species of mammals. Results of lens-weight studies have been reported for cottontails (Sylvilagus floridanus) and gray fox (Urocyon cinereoargenteus) by Lord (1959, 1961); raccoon (Procyon lotor) by Sanderson (1961); fox squirrel (Sciurus niger) by Beale (1962); and pronghorn antelope (Antilocapra americana) by Kolenosky and Miller (1962). Campbell and Tomlinson (1962) applied the lens-weight technique and found it possible to separate adult and juvenile Turkish chukars (Alectoris graeca) but not adult year classes. Payne (1961) reported little success with aging by lens weight in a study of the house sparrow (Passer domesticus). MATERIALS AND METHODS Left eyeballs were taken at road check stations from sharp-tailed grouse bagged in western South Dakota on September 21 and 22, 1963. Sex determination was made using central-tail-feather pattern or gonadal examination. Age was determined by examination of the pattern of primary molt or probe of the bursa. Birds of questionable age or sex were excluded from the sample. Eyeballs were placed in containers of 10 percent formalin solution, labeled by sexand age-classes. Lenses were extracted from the eyeball after about 6 weeks, rolled gently in the fingers to remove traces of the ciliary attachment, and oven-dried at 80 C for at least 72 hours. The dried lenses were weighed on an electrical balance to 0.0001 gram. Although hygroscopic in nature, the lenses tested did not pick up measurable amounts of moisture from the air for a period of over 2 minutes, while the weighing process required about 30 seconds. RESULTS AND DISCUSSION Using the standard t test, lens weights of 162 juvenile males were significantly greater (t = 6.27, P < 0.01) than those of 190 juvenile females (Table 1). Similarly, lens weights of 51 adult males were significantly greater than those of 83 adult females (t = 6.69, P < 0.01). 1 This report is a contribution from Federal Aid in Wildlife Restoration Project in South Dakota W-75-R.

Mammal populations are declining due to habitat fragmentation and loss, but protected areas can maintain these populations at viable numbers and reduce their risk of extinction. This study assessed the mammal community composition, diversity profiles, seasonal variation, and habitat use in a protected area in the Brazilian Atlantic Forest. With an effort of 5,023 camera trap days, we registered 1,889 independent records of 20 species, with an additional 13 species recorded through direct observation. There was no difference in the seasonal diversity profiles of mammal communities. The diversity in submontane areas was consistently larger than in lowland ones, but the number of records was higher in lowland areas. The diversity profiles decrease when more weight is given to the common species. The reserve is the protected area with the third highest mammal richness in the state of Rio de Janeiro and harbors 11 threatened mammals. This study shows the importance of small protected areas for the conservation of mammalian diversity in a fragmented anthropogenic landscape.

The abundance and distribution of Amblyomma americanum (L.) and Dermacentor variabilis (Say) among nine species of medium-sized mammals were examined at an integrated tick management site at Land Between the Lakes, Tennessee, from 1984 to 1986. The most important hosts (mean abundance) during April to October for immature A. americanum were the raccoon, striped skunk, Eastern cottontail rabbit, and Virginia opossum. The medium-sized mammals examined had low numbers of adult A. americanum. Immature D. variabilis were mostly on raccoon and gray squirrel. The main hosts of adult D. variabilis were raccoons and opossums. Acaricide treatment and mowing of campsites, playgrounds, and roadways reduced the number of subadult A. americanum on opossums (64% nymphs, 76% larvae) and cottontail rabbits (86% nymphs, 86% larvae), but appeared to have no effect on D. variabilis infestation of opossums. Deer removal contributed to a reduction in the number of subadult A. americanum on opossums and rabbits inside and outside a deer exclusion. The importance of medium-sized mammals in reinfesting recreation areas with ticks is discussed.

The need for studies on the ability of various wildlife species to survive and the factors affecting their survival has become increasingly important in wildlife management research. Such information is not only essential for an understanding of population behavior but also for planning habitat improvement programs designed to meet specific requirements. One approach toward obtaining physiological information of this type is by subjecting an animal to an applied stress and measuring its resistance and survival time. Kabat, Meyer, Flakas, and Hine (1956) in Wisconsin carried out a series of experiments throughout the year on hen pheasants (Phasianus colchicus torquatus) in which they subjected the birds to the artificial stress of caging and starvation and measured the birds' resistance in terms of body-weight loss and body-temperature decline. The design of their studies was based on Selye's (1949) hypothesis that adaptation to a specific stress (such natural stresses as egg laying, molting, etc.) lowers the body's resistance to different stress to which the animal is not adapted. The applied stress, therefore, was used as a means of demonstrating whether there was seasonal variation in adaptation energy, and which of the naturally occurring physiological stresses caused the greatest decrease in resistance. These studies showed that the use of this technique appeared to produce reliable trends in stress resistance and survival time. There was variation in the hen pheasant's ability to survive the applied stress at different times of the year; this variation in stress resistance and survival time, furthermore, was related to the physiological condition of the hen. The hen pheasant studies opened the door to much more investigation along these lines. During the course of the Wisconsin pheasant experiments in January to March 1951, single tests were run on Hungarian partridge (Perdix perdix), chukar partridge (Alectoris graeca chukar), and cottontail rabbits (Sylvilagus floridanus). The purpose of this report is to present the results of these tests in order to document the data and provide background information for other investigators contemplating similar studies.