Effects of hunting on cougar spatial organization

The effects of increased mortality on the spatial dynamics of solitary carnivores are not well understood. We examined the spatial ecology of two cougar populations that differed in hunting intensity to test whether increased mortality affected home range size and overlap. The stability hypothesis predicts that home range size and overlap will be similar for both sexes among the two areas. The instability hypothesis predicts that home range size and overlap will be greater in the heavily hunted population, although may differ for males versus females due to behavior strategies. We marked 22 adult resident cougars in the lightly hunted population and 20 in the heavily hunted population with GPS collars from 2002 to 2008. Cougar densities and predation rates were similar among areas, suggesting no difference in per capita resources. We compared home range size, two‐dimensional home range overlap, and three‐dimensional utilization distribution overlap index (UDOI) among annual home ranges for male and female cougars. Male cougars in the heavily hunted area had larger sized home ranges and greater two‐dimensional and three‐dimensional UDOI overlap than those in the lightly hunted area. Females showed no difference in size and overlap of home range areas between study populations – further suggesting that differences in prey quantity and distribution between study areas did not explain differences in male spatial organization. We reject the spatial stability hypothesis and provide evidence to support the spatial instability hypothesis. Increased hunting and ensuing increased male home range size and overlap may result in negative demographic effects for cougars and potential unintended consequences for managers.     

Seasonal locomotion and home-range characteristics of European hares (<Emphasis Type="Italic">Lepus europaeus</Emphasis>) in an arable region in central Germany

We studied seasonal use of space by 38 radio-tracked European hares in an arable region in central Germany over 5 years. Mean distance between successive daytime and nighttime fixes of a hare amounted to 226 m, and an average distance of 172 m was recorded for successive daytime fixes. The hares shifted the centres of their home ranges from one 2-month period to the next by an average distance of 131 m and over a time span of 11.2 months by 216 m. The size of their 2-month home ranges (MCP 95) averaged 21 ha; the variation between individuals was high. Night ranges were larger than day ranges. Mean size of seasonal home ranges—based on daytime and nighttime fixes—remained largely constant throughout the year. Home-range size increased as the day-to-night distance increased, as the number of used habitat elements increased and as frequency of use of inner field parts during the daytime increased. Home-range size was inversely related to population density. On average, 32% of the area of the home range of a hare overlapped with the home range of a neighbouring conspecific. When related to the population density of adult hares in spring, the home range of a single hare was estimated to overlap with 13–21 home ranges of adults as well as an indefinite number of juveniles. The large intraseasonal variation in locomotion and home-range characteristics is interpreted in relationship to the social structure of European hares.     

Effects of high density on spacing behaviour and reproduction in Akodon azarae: A fencing experiment

We studied the short term spacing behavioural responses of Pampean grassland mouse (Akodon azarae) with regard to population density in four 0.25 ha enclosures (two control and two experimental) in the 2011 breeding season. Based on the hypothesis that A. azarae breeding females exhibit spacing behaviour, and breeding males show a fusion spatial response, we tested the following predictions: (1) home range size and intrasexual overlap degree of females are independent of population density values; (2) at high population density, home range size of males decreases and the intrasexual home range overlap degree increases. To determine if female reproductive success decreases at high population density, we analyzed pregnancy rate, size and weight of litters, and period until fecundation in both low and high enclosure population density. We found that both males and females varied their home range size in relation to population density. Although male home ranges were always bigger than those of females in populations with high density, home range sizes of both sexes decreased. Females kept exclusive home ranges independent of density values meanwhile males decreased home range overlap in high breeding density populations. Although females produced litters of similar size in both treatments, weight of litter, pregnant rate and period until fecundation varied in relation to population density. Our results did not support the hypothesis that at high density females of A. azarae exhibit spacing behaviour neither that males exhibit a fusion spatial response.     

Population densities and home range sizes of the Chestnut Wood-quail

ABSTRACT.   We present the first report of population density and home range estimates for the Chestnut Wood-quail ( Odontophorus hyperythrus ), an endemic and nearly threatened species of the Colombian Andes. Density estimates were obtained using playbacks and spot mapping and point transect methods. Home range sizes were estimated by radio tracking five wood-quail. Estimated densities varied from 0.3 to 0.4 groups per hectare. These densities are similar to those reported for other mountain wood-quail, but higher than those for lowland wood-quail and other species in the family Odontophoridae. Estimates of home range size varied from 2.6 to 9.0 hectares per group, and seemed to be correlated with group size. We also found evidence of overlap in the home ranges of neighboring groups. Population densities may vary with factors such as habitat type, but our estimates allow a first approximation of the population sizes of Chestnut Wood-quail in forest fragments.     

Social Spacing in Small Mammals: Patterns of Individual Variation

The pattern of social spacing in small mammals differs fromthat observed in many other vertebrates. Small mammals frequentlyhave non-exclusive territories and tolerate a large amount ofoverlap with other conspecifics. The determinant factors ofhome range or territory size in small mammals are not knownfor most species. We carried out a study of the determinantfactors of home range size in a model small mammal, the easternchipmunk, Tamias striatus. The population was studied for fiveyears. The effect of experimental perturbations on food supplyand population density offered strong evidence that the meanhome range size in the population was determined by resourceabundance. Changes in population density had little or no measurableeffect. We noted that even when mean home range size decreasedsignificantly in response to an increase in available food,a great deal of variability in individual home range sizes remained.We hypothesized that this pattern of variation among individualswas also resource related; large home ranges would be locatedin areas of low resource density and small home ranges wouldbe located in areas of high resource density. Our data to datedo not offer support for this hypothesis; however our researchhas shown that the data needed to convincingly reject the nullhypothesis are very complex. We discuss the evidence requiredto study patterns of individual variation, and how models ofoptimal territory size may be useful. Research that examinespatterns of individual variation are few in number, yet studiesof individual variation will ultimately provide the best insightson the dynamics of evolutionary ecology.     

Happily together forever: temporal variation in spatial patterns and complete lack of territoriality in a promiscuous rodent

The availability of resources, their effect on population density and territoriality, and the ways in which these factors are interwoven with mating systems are important determinants of small mammal space use. It is often difficult to study these patterns in an integrated way, however, especially because long-term data are needed but not readily available. In this paper, we investigate effects of population density, season and breeding status on home range patterns of the promiscuous rodent Mastomys natalensis using monthly capture-mark-recapture data collected over 17 years in a 3-ha grid. Home ranges were estimated using minimum convex polygons bounded by trap locations, and home range overlap and visitation rates were calculated as a measure of territoriality. As higher population densities coincide with increased resource availability, we predicted that home range sizes would correlate negatively with density. Furthermore, as M. natalensis is promiscuous and population densities are generally high, we predicted that territoriality would be low, and home range overlap would therefore be high. Contrary to expectations the home ranges of female adults increased with population density, although those of male adults and subadults followed the expected decrease. Home range overlap and visitation rates were generally high, and increased significantly with population density. More importantly, they were never lower than those of simulated datasets consisting of randomly moved home ranges. These results therefore suggest that M. natalensis displays a complete lack of territoriality that is rarely seen in small mammals but still meets predictions based on knowledge of density and mating system.     

Negative effects of density on space use of small mammals differ with the phase of the masting‐induced population cycle

Home range size generally decreases with increasing population density, but testing how this relationship is influenced by other factors (e.g., food availability, kin structure) is a difficult task. We used spatially explicit capture–recapture models to examine how home range size varies with population density in the yellow‐necked mouse (Apodemus flavicollis). The relationship between population density and home range size was studied at two distinct phases of population fluctuations induced by beech (Fagus sylvatica) masting: post‐mast peak in abundance (first summer after mast, n = 2) and subsequent crash (second summer after mast, n = 2). We live‐trapped mice from June to September to avoid the confounding effects of autumn seedfall on home range size. In accordance with general predictions, we found that home range size was negatively associated with population density. However, after controlling for the effect of density, home ranges of mice were larger in post‐mast years than during the crash phase. This indicates a higher spatial overlap among neighbors in post‐mast years. We suggest that the increased spatial overlap is caused by negative density‐dependent dispersal that leads to high relatedness of individuals within population in the peak phase of the cycle.     

Intraspecific Variation in Home Range Overlap with Habitat Quality: A Comparison among Brown Bear Populations

We developed a conceptual model of spatial organization in vertebrates based upon changes in home range overlap with habitat quality. We tested the model using estimates of annual home ranges of adult females and densities for 30 populations of brown bears (Ursus arctos) in North America. We used seasonality as a surrogate of habitat quality, measured as the coefficient of variation among monthly actual evapotranspiration values for areas in which study populations were located. We calculated home range overlap for each population as the product of the average home range size for adult females and the estimated population density of adult females. Home range size varied positively with seasonality; however, home range overlap varied with seasonality in a nonlinear manner. Areas of low and high seasonality supported brown bears with considerable home range overlap, but areas of moderate seasonality supported brown bears with low home range overlap. These results are consistent with behavioural theory predicting a nonlinear relationship between food availability and territoriality.     

Evolutionarily stable consumer home range size in relation to resource demography and consumer spatial organization

There is a large variation in home range size within species, yet few models relate that variation to demographic and life-history traits. We derive an approximate deterministic population dynamics model keeping track of spatial structure, via spatial moment equations, from an individual-based spatial consumer-resource model; where space-use of consumers resembles that of central place foragers. Using invasion analyses, we investigate how the evolutionarily stable home range size of the consumer depends on a number of ecological and behavioral traits of both the resource and the consumer. We show that any trait variation leading to a decreased overall resource production or an increased spatial segregation between consumer and resource acts to increase consumer home range size. In this way, we extend theoretical predictions on optimal territory size to a larger range of ecological scenarios where home ranges overlap and population dynamics feedbacks are possible. Consideration of spatial traits such as dispersal distances also generates new results: (1) consumer home range size decreases with increased resource dispersal distance, and (2) when consumer agonistic behavior is weak, more philopatric consumers have larger home ranges. Finally, our results emphasize the role of the spatial correlation between consumer and resource distributions in determining home range size, and suggest resource dispersion is less important.     

Exclusive core areas and intrasexual territoriality in Eurasian red squirrels (<Emphasis Type="Italic">Sciurus vulgaris</Emphasis>) revealed by incremental cluster polygon analysis

When animal home ranges overlap extensively in species lacking overt territorial behaviours, identifying exclusive core areas within individual ranges can be difficult. By analysing the size and overlap of successively smaller core areas among individual Eurasian red squirrels (Sciurus vulgaris), we determined exclusive areas within the home ranges of resident males and females. Possible effects of habitat composition and food supplies were explored by monitoring squirrels in different conifer forests and during years with low and high tree seed production. Using outlier-exclusive cores (OEC) revealed that the total ranges consisted of large sally zones (on average, 35% of the total minimum convex polygon [MCP] range) around home ranges with multi-nucleate cores. The mean OEC home range size did not differ between the sexes but was larger with poor food availability. Home ranges (99% incremental cluster polygons [ICP]) overlapped extensively between sexes (average overlap high food–low food: males by females 21–40%, females by males 43–45%) and among males (males by males 26–44%), while intrasexual overlap among females was low (9–10%). The overlap of inner cores among females rapidly approached zero, suggesting the intrasexual territoriality of 75% core areas. This was not the case among male squirrels, for which intrasexual overlap averaged only 4% at 50% but 18% at 75% core areas. Even the smallest inner cores had some degree of intersexual overlap, indicating that complete territoriality did not occur in this species. Female home ranges were more strongly affected by annual fluctuations in food supplies than male ranges. Females reduced the size of their food-based intrasexual territories when food availability increases. Males probably benefit from using larger home ranges and core areas, which overlap with the ranges of several females, by increasing their probability of successful mating.     

繁殖期不同时段赤腹松鼠巢域的变化

繁殖期巢域的研究对了解繁殖期间动物的社群关系、种群动态、繁殖策略等有重要作用。2009 年3 ～12月和2010 年3 ～9 月对洪雅县赤腹松鼠的巢域面积变化进行观察。使用最小凸多边形(Minimum convex polygon,MCP)法计算赤腹松鼠各时期的巢域面积,结果显示: (1)整个繁殖期,雄性赤腹松鼠的巢域面积为1.34 ±0. 34 hm² ,显著大于雌性的巢域面积(0.60 ± 0. 08 hm² ); (2)雄性赤腹松鼠在求偶交配期主动增加其巢域面积,可能会增加雄性与雌性的遇见率,从而增加与雌性的交配数量;雌性赤腹松鼠在求偶交配期不主动增加巢域面积,而是具有较为稳定的活动范围。在妊娠育幼期雌性的巢域面积会减小,这可能是雌性为提高后代的成活率,在增加能量和降低捕食风险两者间做出的权衡;(3)整个繁殖期,雌性赤腹松鼠间无巢域重叠现象,而雄性间存在巢域重叠。两性之间仅在求偶交配期存在巢域重叠现象,因此,雌性赤腹松鼠在繁殖期有较强的领域性。     

Comparative density,demography, and ranging behavior of Barbary macaques (Macaca sylvanus) in marginal and prime conifer habitats

A semiisolated study population of 162 Barbary macaques (six groups) inhabiting the Ghomaran fir forests of the Moroccan Rif mountains has a density of 6.73 individuals/km ². The adult sex ratio is 0.725, and immatures comprise 46.9% of the population. Births are seasonal, occurring from April to June, and the adult female birth rate is 0.58 per annum. Mortality appears relatively low in all age classes until old age. Group size ranges from 12 to 59 individuals, with a median value of 24. Home-range sizes vary between 3 and 9 km², with a mean of 7.2 km². Home-range overlap is approximately 80%. On the basis of macaque density, conifer density, and herding competition from domestic animals, the Ghomaran environment can be considered “marginal” compared to the Moyen Atlas. Despite the marginal habitat of the Ghomaran population, it is surprisingly similar in demographic characteristics to a Barbary macaque population in the Moyen Atlas. Two characteristics of the population dynamics in the Ghomara differentiate it from the former. (1) The mean home range is five times larger in the Ghomara, roughly inversely proportional to the sixfold decrease in macaque density, confirming Caldecott’s (1986) principle that, in macaque species, range size adjustments are a primary proximate response to poor-quality habitat. (2) Smaller groups in the marginal habitat of the Ghomara appear to have better rates of growth than small groups in prime habitat. This may result from an overall decreased home-range defensibility in marginal habitat (larger home ranges), resulting in an ecological and demographic release of small groups from the levels of intergroup competition they would normally experience in prime habitat.     

Mating system structure and population density in a polygynous lizard, Sauromalus obesus (= ater)

Increases in population density often are associated with achange in mating system structure in numerous taxa. Typically,male interactions are minimal in extremely low density populations.As density increases, males exhibit territoriality but if densitybecomes too high, the energetic cost of defending a territorywill eventually outweigh the reproductive benefits associatedwith territoriality. Consequently, males in high density populationsmay abandon territoriality and adopt dominance polygyny, lekking behavior, or scramble competition. We investigated the relationshipbetween population density and mating system structure in threepopulations of the chuckwalla, Sauromalus obesus (= ater),near Phoenix, Arizona. Densities in the Phoenix Mountains (2.7chuckwallas/ha) were lower than any population previously studied.In the Santan Mountains (10.9 chuckwallas/ha), densities weresimilar to populations studied in the Mojave Desert, and inthe South Mountains (65 chuckwallas/ha), densities were the highest yet recorded. Male mating behavior was examined by determininghome range overlap and by making direct behavioral observations.Male home range size decreased with increasing population density.There was little overlap in home ranges among males in allthree populations, whereas home ranges of males and femalesconsistently overlapped, indicating that males were strictly territorial. This conclusion was supported by behavioral observationsof interactions among individuals in a natural setting. Thenumber of females wihin male territories was correlated withfood resources (plants) in all three populations. Female homerange size appeard to be related to food resources whereasmale home ranges appeared to be related to female distribution,population density, and geology. The retention of territoriality in spite of high population densities raises new questions aboutthe relationship between density and resource defense.     

Density‐dependent space use affects interpretation of camera trap detection rates

Camera traps (CTs) are an increasingly popular tool for wildlife survey and monitoring. Estimating relative abundance in unmarked species is often done using detection rate as an index of relative abundance, which assumes that detection rate has a positive linear relationship with true abundance. This assumption may be violated if movement behavior varies with density, but the degree to which movement behavior is density‐dependent across taxa is unclear. The potential confounding of population‐level relative abundance indices by movement would depend on how regularly, and by what magnitude, movement rate and home‐range size vary with density. We conducted a systematic review and meta‐analysis to quantify relationships between movement rate, home‐range size, and density, across terrestrial mammalian taxa. We then simulated animal movements and CT sampling to test the effect of contrasting movement scenarios on CT detection rate indices. Overall, movement rate and home‐range size were negatively correlated with density and positively correlated with one another. The strength of the relationships varied significantly between taxa and populations. In simulations, detection rates were related to true abundance but underestimated change, particularly for slower moving species with small home ranges. In situations where animal space use changes markedly with density, we estimate that up to thirty percent of a true change in relative abundance may be missed due to the confounding effect of movement, making trend estimation more difficult. The common assumption that movement remains constant across densities is therefore violated across a wide range of mammal species. When studying unmarked species using CT detection rates, researchers and managers should explicitly consider that such indices of relative abundance reflect both density and movement. Practitioners interpreting changes in camera detection rates should be aware that observed differences may be biased low relative to true changes in abundance. Further information on animal movement, or methods that do not depend on assumptions of density‐independent movement, may be required to make robust inferences on population trends.     

Spatial organization of leopards Panthera pardus in Taï National Park, Ivory Coast: is rainforest habitat a 'tropical haven'?

Between June 1992 and July 1994, two female leopards and one male were radio-tracked. Regular locations of the leopards, the use of a phototrap, and spoor data, provided the first detailed ecological data about this elusive felid in tropical rainforest habitat. The home range of the male was 86 km², those of the two females were 29 km² and 22 km², respectively. One female's home range was fully included within that of the male. Home ranges of neighbouring residents were not exclusive. Population density is estimated at one leopard per 9-14 km². Intraspecific interactions were rare and predominantly involved mating. The large size of the home ranges and a relatively high population density imply large overlap between adjacent resident leopards' ranges. Differences in the leopard's land tenure system between the rainforest and the savanna are discussed. Doubt is cast on the validity of the often-quoted estimate of one leopard per 1 km² in tropical rainforest habitat.     

Woodland fragmentation affects space use of Eurasian red squirrels

When habitats become fragmented, variation in patch size and quality are expected to impose changes on the spacing pattern and social organization of animal populations. General theory predicts different possible responses including shrinking home ranges (fission response), increasing range overlap (fusion) and incorporation of multiple patches in the home range (expansion response) as fragmentation increases. We studied space use and social organization in a metapopulation of red squirrels (Sciurus vulgaris) in 15 woodland fragments differing in size and tree species composition. Home ranges and core areas of males were larger than females, and fragmentation had different and complex effects on the spacing pattern of both sexes. In food-supplemented patches, high densities led to increased intra-sexual overlap. In linear-shaped patches, squirrels used smaller home ranges and core areas and had lower male–male and male–female overlap levels, independent of patch quality or size. Home range and core area size of males increased with patch size, and male core areas overlapped extensively those of other males and females. Hence males seemed to show a fission response only in some patches. In contrast, home range and core area size of females was not related with patch size, but decreased with habitat quality, supporting predictions of a fusion response and intra-sexual defense of food-based core areas. Hence, where patch size and shape strongly affected space use of male red squirrels, social organization of females was only affected in small, food-supplemented patches, suggesting that the basic spatio-social organization of adult females is very resistant to fragmentation.     

Space use and site fidelity of wintering whooping cranes on the Texas Gulf Coast

The Aransas-Wood Buffalo population (the only non-reintroduced, migratory population) of endangered whooping cranes (Grus americana) overwinters along the Texas Gulf Coast, USA. Understanding whooping crane space use on the wintering grounds reveals essential aspects of this species' ecology, which subsequently assists with conservation. Using global positioning system telemetry data from marked whooping cranes during 2009–2017, we fit continuous-time stochastic process models to describe movement and home range using autocorrelated kernel density estimation (AKDE) and explored variation in home range size in relation to age, sex, reproductive status, and drought conditions. We used the Bhattacharyya coefficient of overlap and distance between home range centroids to quantify site fidelity. We examined the effects of time between winter home ranges and the sex of the crane on site fidelity using Bayesian mixed-effects beta regression. Winter whooping crane 95% AKDE home range size averaged 30.1 ± 45.2 (SD) km² (median = 14.3, range = 1.1–308.6). Home ranges of sub-adult females were approximately 2 times larger than those of sub-adult males or families. As drought worsened, home ranges typically expanded. Between consecutive years, the home ranges of an adult crane exhibited 68 ± 31% overlap (site fidelity), but fidelity to winter sites declined in subsequent winters. The overlap of adult home ranges with the nearest unrelated family averaged 33 ± 28%. As a whooping crane aged, overlap with its winter home range as a juvenile declined, regardless of sex. By 4 years of age, a whooping crane had approximately 14 ± 28% overlap with its juvenile winter home range. Limited evidence suggested male whooping cranes return to within 2 km of their juvenile home range by their fifth winter. Previous data obtained from aerial surveys led ecologists to assume that whooping crane families normally used small areas (~2 km²) and expressed persistent site fidelity. Our analyses showed <8% of families had home ranges ≤2 km², with the average area 15 times greater, and waning site fidelity over time. Our work represents an analysis of whooping crane home ranges for this population, identifying past misconceptions of winter space use and resulting in better estimates of space requirements for future conservation efforts.     

Time Budgets and Territory Size: Some Simultaneous Optimization Models for Energy Maximizers

A set of optimization models in two variables of choice, territorysize and time spent patrolling for intruders, is presented forenergy maximizers. Models vary in the curvilinearity of therelationship between territory circumference and both intrusionrate and cost of expelling a single intruder. Models are analyzedboth with and without constraints; constraints are on processingrate and on the time spent patrolling, feeding and activelydefending. The models all include the concept of "intruder equilibrium,"an equilibrial density of intruders in a territory resultingfrom a balance between intrusion rate and expulsion by the defender.This equilibrial density can be considered a measure of territorialexclusiveness. The two-variable models predict effects on territory size andpatrol time of variation in food density, intrusion rate, costsof expelling a single intruder in energy and time, food-consumptionrate of an intruder, area of detection while patrolling, totaltime available for territorial and feeding activities, timeto eat a unit of food energy, energy cost of patrol per time,and processing-rate capacity. With increasing intruder rate,optimal territory size usually decreases, whereas optimal patroltime behaves much more irregularly. With increasing food density,optimal patrol time usually decreases, whereas optimal territorysize behaves irregularly. In particular, when intrusion rateand expulsion costs accelerate sufficiently with increasingterritory size and no constraints exist, the higher the fooddensity the smaller the optimal territory size. When food densityis large enough for a constraint to be effective, the oppositerelation can hold and will always hold for a processing constraint. When a particular parameter changes, optimal territory sizeand optimal patrol time may covary or one may increase whilethe other decreases, depending on the parameter and model. A new set of one-variable models is suggested by the two-variablemodels; models optimizing patrol time while holding territorysize constant could correspond to a tightly packed system ofterritories initially determined by settlement patterns. A unifiedonevariable analysis suggests that how food density affectsterritory size when patrol time is constant depends upon whethera constraint is operating: Provided that invasion rate doesnot vary with density of intruders on the territory, time minimizersand constrained energy maximizers decrease territory size withincreasing food density; unconstrained energy maximizers dothe opposite. The addition of a second optimization variable to a one-variablemodel can change qualitative predictions about variation inparticular parameters (e.g., food density) and can increasethe number of parameters predicted to affect optimal territorysize and patrol time.     

Dynamic models of infectious diseases as regulators of population sizes

Five SIRS epidemiological models for populations of varying size are considered. The incidences of infection are given by mass action terms involving the number of infectives and either the number of susceptibles or the fraction of the population which is susceptible. When the population dynamics are immigration and deaths, thresholds are found which determine whether the disease dies out or approaches an endemic equilibrium. When the population dynamics are unbalanced births and deaths proportional to the population size, thresholds are found which determine whether the disease dies out or remains endemic and whether the population declines to zero, remains finite or grows exponentially. In these models the persistence of the disease and disease-related deaths can reduce the asymptotic population size or change the asymptotic behavior from exponential growth to exponential decay or approach to an equilibrium population size.Research supported by Centers for Disease Control contract 200-87-0515. Support services provided at the University of Iowa Center for Advanced Studies     

Home range size variation in a recovering wolf population: evaluating the effect of environmental, demographic, and social factors

Home range size in mammals is a key ecological trait and an important parameter in conservation planning, and has been shown to be influenced by ecological, demographic and social factors in animal populations. Information on space requirements is especially important for carnivore species which range over very large areas and often come into direct conflict with human interest. We used long-term telemetry-location data from a recovering wolf population in Scandinavia to investigate variation in home range size in relation to environmental and social characteristics of the different packs. Wolves showed considerable variation in home range size, which ranged from 259 to 1,676 km². Although wolf density increased fourfold during the study period, we found no evidence that intraspecific competition influenced range size. Local variation in moose density, which was the main prey for most packs, did not influence wolf home range size. Home ranges increased with latitude and elevation and decreased with increased roe deer density. Although prey biomass alone did not influence range size, our data suggest that there is a correlation between habitat characteristics, choice of prey species and possible hunting success, which currently combine to shape home range size in Scandinavian wolves.