Diurnal space use and nocturnal roost‐site selection by male Cerulean Warblers during the breeding season

Detailed information about space use during the breeding season is limited for most Nearctic‐Neotropical migratory species of songbirds because of their small size and often cryptic behaviors. We monitored male Cerulean Warblers (Setophaga cerulea), a species of conservation concern, using radio‐telemetry during the 2006–2008 breeding seasons in northern Alabama to better understand their space use and habitat selection. We estimated diurnal home range and core areas using information theoretic criteria, located nocturnal roost sites, and related day and evening locations to surrounding landscape habitat, including features representative of canopy disturbances. Mean home range size was 6.7 ha (N = 10), and home ranges included an average of at least 2 core areas encompassing 0.7 ha. We located 53 nocturnal roost sites that were an average 159.0 m from the center of the nearest core area. More than one‐third (36.6%) of roost sites were located outside the diurnal home ranges of male Cerulean Warblers; only 13.6% were located in core areas. Males in our study moved much farther than reported in previous studies, with some singing in areas > 300 m from previously used song perches, a behavior suggesting pursuit of extra‐pair copulations. Cerulean Warblers in our study preferentially selected a heavily forested landscape composed of mesic, floodplain bottomlands with little man‐made disturbance. Within their home ranges, diurnal locations of males in core areas were located significantly closer to a creek than locations outside of core areas. Our results suggest that male Cerulean Warblers require much larger areas than previously reported and underscore the importance of a predominately forested landscape in their habitat selection process. Although edge habitats appeared to influence space use by male Cerulean Warblers in our study, the extent to which this is an essential requirement is unclear. Our results and those of previous studies suggest that specific habitat requirements of this species can vary at the local scale throughout its breeding range.     

Space use by Great Lakes Piping Plovers during the breeding season

ABSTRACT.   Identifying and protecting breeding habitat for imperiled species requires an understanding of the spatial and temporal movements of breeding individuals. During the 2003 and 2004 breeding seasons, we examined space use by Piping Plovers ( Charadrius melodus ) in the federally endangered Great Lakes population. We used coordinate geometry to estimate home range sizes of individual birds and examined relationships between home range size and breeding stage (incubation versus chick rearing), year, sex, number of locations, minimum plover age, distance to the nearest nest, and human beach use (high, medium, or low). The mean size of home ranges of Piping Plovers that fledged at least one chick was 2.9 ± 0.5 (SE) ha (range = 0.4–11.2 ha), and the mean linear beach distance traversed was 475 ± 53 m (range = 130–1435 m). Individuals used 3 times more beach area and 1.5 times more shoreline distance in 2003 than in 2004. Females used smaller areas than males overall and during chick rearing. Home ranges were smallest on beaches with low public use, suggesting that human disturbance may cause greater movement by individual plovers and that larger protected areas may be warranted on beaches frequented by the public to minimize disturbance to breeding birds. Our results demonstrate that nesting Great Lakes Piping Plovers occupy relatively small ranges and, therefore, that even relatively small areas of suitable habitat can have a high conservation value for this endangered population. However, the total area of habitat used varied substantially among individuals, and this should be considered when protecting habitat for the species.     

The endangered White's seahorse Hippocampus whitei chooses artificial over natural habitats

To explore whether the endangered White's seahorse Hippocampus whitei would choose to inhabit artificial over natural habitats, 10 adult H. whitei individuals were put through a series of binary choice trials in aquaria, during which they were offered different paired combinations of natural (different types of macroalga and seagrass) and artificial habitat (panels of swimming-net material). It was found that H. whitei displayed a significant choice for swimming-net material over all other available natural habitats and chose habitats according to the following rankings: (a) Net; (b) Sargassum sp.; (c) Posidonia australis; (d) Zostera muelleri. Hippocampus whitei’s choice of swimming net material over natural habitat suggests that these artificial structures could be a useful conservation measure for seahorses in areas where natural habitat is becoming less favourable due to declines in abundance or quality.     

Land use patterns within Wattled Crane (Bugeranus carunculatus) home ranges in an agricultural landscape in KwaZulu-Natal,South Africa

There The Wattled Crane Bugeranus carunculatus is one of the top five most threatened bird species in South Africa, with the main threat being the loss of undisturbed breeding habitat. A basic understanding of this species' use of its environment is needed to implement conservation action. This quantitative study focused on determining the home range size of active breeding pairs in the KwaZulu-Natal midlands of South Africa, and assessing the land use composition of these home ranges. Wattled Cranes were found to have an average home range size of 16.64km², consisting mostly of open natural grassland (mean of 75.5% of the overall home range of pairs). Other significant land use contributions to the home ranges were temporary irrigated and dryland cultivated agriculture. The core breeding area (wetland) of the home range constituted only 2.3% of the overall home range size, consisting of similar proportions of both wetland (48.9%) and grassland (51.8%) habitat. This indicates the dependence of Wattled Cranes on specific wetland habitats, surrounded by natural grassland. Wattled Cranes show home range sizes larger than other similar-sized crane species, suggesting that this may be as a result of their large body size and their occupation of highly transformed and fragmented habitats in an agricultural landscape. However, the occurrence of transformed land use types in home ranges suggests that breeding pairs tolerate some degree of disturbance within their home ranges. The home ranges do not appear to be currently restricted by surrounding land use types, indicating that factors other than habitat loss may be contributing to breeding site losses. The study has therefore indicated the need for closer working relationships between conservationists and agricultural communities to promote the conservation of valuable natural grasslands surrounding wetlands.     

Ranging Movements of Female Roe Deer: Do Home-loving Does Roam to Mate?

Bimonthly changes in home range size of seven mature roe deer Capreolus capreolus L. females were analysed over one year. Great stability of home range size and high site fidelity was common to all females, which remained bimonthly within areas of 6.1–20.8 ha. Two groups of females could be identified on the basis of bimonthly variations in their home range sizes: females with larger areas (LHR females), who decreased their ranges in the birth season only, and females with smaller home ranges (SHR females), who increased significantly their home ranges during the rut. The most likely explanation is that the areas inhabited by SHR females included high-quality food resources allowing survival even in small home ranges. In the rut, SHR females may have expanded their ranges to increase mating opportunities.     

Space use patterns of mountain hare (<Emphasis Type="Italic">Lepus timidus</Emphasis>) on the Alps

Populations on the limits of species’ distribution can show different behavioral adaptations to strong ecological pressure than in the central part of the range. We investigated space use patterns of alpine mountain hare (Lepus timidus) at two areas on the southern edge of the species’ range. We monitored 34 hares between 2005 and 2008, estimating home range size, overlap, and site fidelity, and compared our results with space use in Scottish and North-European populations. Home ranges of mountain hares did not differ between two study areas with different habitat types. Subadult animals used larger ranges than adults and both age groups reduced home range size in autumn, a period that might be critical for hares due to changes in diet and/or high energy expenditure during the previous breeding season. Home ranges in these alpine populations were smaller than in Scandinavian populations but within the range of populations in different habitat types in Scotland. Seasonal home ranges overlapped considerably, but differed among the sexes: male–female overlap was higher than same sex (male–male and female–female) spatial overlap. Seasonal shifts of home ranges were small, and site fidelity remained high over the seasons, suggesting that resource distribution remained constant throughout the year and that the knowledge of an intensively frequented area is an important element of habitat quality. We concluded that habitat structure and availability of mates interact in affecting mountain hare space use in alpine habitats.     

Home range use and the exploitation of gum in the marmosetCallithrix jacchus jacchus

Three wild groups of common marmoset, Callithrix jacchus jacchus,in north-east Brazil, of approximately similar size, had home ranges between 2.5 and 6.5 ha. But their core areas were similar in size between 1.0 and 1.5 ha, with a monthly area of heavy use between 1.1 and 1.6 ha. The groups were selective in the use of their home ranges, even though they were small: they used some areas heavily and others lightly. The core areas had higher densities of trees that produced gum exudates than did other parts of the home ranges. Our data suggest that a group of marmosets in this habitat may require a minimum of about 50 gum trees in its home range at a minimum density of about 50 trees/ha. In addition, the animals require suitable trees in which to sleep. We suggest that patches of forest with these desirable properties remain relatively fixed in size and location over the years and that individual animals are constantly in flux between them.     

Home ranges in red fox: territoriality diminishes with increasing area

Red foxVulpes vulpes (Linnaeus, 1758) are generally regarded as strictly territorial animals, inhabiting distinct and well-separated ranges. The home ranges of these predators can vary in size from a few dozen hectares to as much as 20–30 km². Because it seemed impossible that foxes could defend areas so different in size with the same intensity, the published data were analysed in order to see how changes in home range size could affect the following parameters: home range overlap, the area visited daily and the distance travelled by animals during 24 h. It was found that the overlap between fox families (groups) occupying large ranges was much greater than between foxes living in small ranges. The ratio of the area visited daily to the seasonal home range size was greater in small ranges than in large ones. No significant correlation was found between the mean distance moved daily and home range size (r = −0.118,p = 0.75). These results suggest different patterns of the use of space and differences in territorial defence by red foxes inhabiting large and small ranges. The implications of home range overlap and intensity of contacts between foxes occupying neighbouring ranges for the spread of disease are discussed. The significant overlap between large ranges found in this paper is discussed in the light of Andrzejewski’s (2002) home range concept.

     

Identifying key habitats for the conservation of Bonelli's Eagle Aquila fasciata using radiotracking

Identifying the priority habitats of endangered species is crucial to implementing effective conservation actions. We characterize the key habitats used by Bonelli's Eagle Aquila fasciata, an umbrella and flagship species that is endangered in Mediterranean countries. We radiotracked 17 breeding individuals (10 males and seven females) in Catalonia (NE Iberian Peninsula) and used compositional analysis to determine the key habitats in home‐ranges of both sexes. The main habitats identified within the home‐range area were scrubland, coniferous forests, cropland, sclerophyllous forests, rock outcrops and urban areas, with little difference in habitat use between the sexes. Bonelli's Eagles preferred rocky habitats as breeding areas and scrubland as foraging areas, as these hold the highest abundance of their main prey, Rabbits Oryctolagus cuniculus and Red‐legged Partridges Alectoris rufa. Habitat selection varied seasonally in foraging areas: scrubland was the most preferred habitat type during the breeding season, whereas rocky areas were preferred during the non‐breeding season (although scrubland was also highly selected). Urban areas were avoided both as breeding and as foraging areas. Home‐range size was inversely correlated with the proportion of scrubland, suggesting that this is a key habitat for Bonelli's Eagle. To conserve this species effectively, policies that ensure the preservation of the cliffs used as breeding sites, as well as suitable management of the scrubland used for foraging, should be implemented in the areas inhabited by this species. The promotion of traditional land uses and management techniques that will enhance open areas in Mediterranean landscapes should in the future play an essential role in the conservation of Bonelli's Eagle in Mediterranean habitats.     

Spacing Behavior of a Non‐Larder‐Hoarding Tamiasciurus: A Study of Mearns's Squirrels in Xeric Coniferous Forests

In ecosystems with seasonal fluctuations in food supply many species use two strategies to store food: larder hoarding and scatter hoarding. However, because species at different geographic locations may experience distinct environmental conditions, differences in hoarding behavior may occur. Tree squirrels in the genus Tamiasciurus display variation in hoarding behavior. Whereas red (Tamiasciurus hudsonicus) and Douglas's (Tamiasciurus douglasii) squirrels in mesic coniferous forests defend territories centered around larder hoards maintaining non‐overlapping home ranges, red squirrels in deciduous forests defend small scatter‐hoarded caches of cones maintaining overlapping home ranges. As in other rodent species, variation in hoarding behavior appears to influence the spacing behavior of red and Douglas's squirrels. In contrast, Mearns's squirrels (Tamiasciurus mearnsi) in xeric coniferous forests neither rely on larder hoards nor appear to display territorial behavior. Unfortunately, little is known about the ecology of this southernmost Tamiasciurus. Using radiotelemetry, we estimated home‐range size, overlap, and maximum distance traveled from nest to examine the spacing behavior of Mearns's squirrels. Similar to scatter‐hoarding rodents, maximum distance traveled from nest was greater for males during mating season, whereas those of females were similar year round. Although no seasonal differences were detected, male home ranges were three times larger during mating season, whereas those of females were smaller and displayed a minor variation between seasons. Home ranges were overlapped year round but contrary to our expectations, overlap was greater during mating season for both sexes, with no detectable relationship between male home‐range size and the number of females overlapped during mating season. Overall, the results appear to support our hypothesis that in the absence of larder hoards, the spacing behavior of Mearns's squirrels should be different from larder‐hoarding congeners and more similar to scatter‐hoarding rodents.     

Differential Range Use between Age Classes of Southern African Bearded Vultures Gypaetus barbatus

Bearded Vulture Gypaetus barbatus movements were investigated in southern Africa to determine whether an individual''s age, sex or breeding status influenced its ranging behaviour and to provide the information required to guide conservation activities. Data from satellite transmitters fitted to 18 individuals of four age classes were used to determine range size and use. Because of the nature of the movements of marked individuals, these data could be used to determine the overall foraging range of the entire population, which was estimated to be 51 767 km². Although juvenile, immature and sub-adult birds used different parts of the overall range, their combined foraging range was 65% (33 636 km²) of the overall range. Average adult home ranges (286 km²) were only around 1% the size of the average foraging ranges of non-adults (10 540 –25 985 km²), with those of breeding adults being even smaller (95 km²). Home ranges of breeding adults did not vary in size between seasons but adults utilized their home range more intensively whilst breeding, moving greater distances during the incubation and chick hatching period. Range size and use increased as non-adults aged. Immatures and sub-adults had larger range sizes during winter, but range use of non-adults did not vary seasonally. Range size and use did not differ between the sexes in any of the age classes. Information on home range size and use enables specific areas within the species'' range to be targeted for management planning, education and conservation action.     

Seasonal home range dynamics and sex differences in habitat use in a threatened,coastal marsh bird

A comprehensive understanding of spatiotemporal ecology is needed to develop conservation strategies for declining species. The king rail (Rallus elegans) is a secretive marsh bird whose range historically extended across the eastern United States. Inland migratory populations have been greatly reduced with most remaining populations inhabiting the coastal margins. Our objectives were to determine the migratory status of breeding king rails on the mid‐Atlantic coast and to characterize home range size, seasonal patterns of movement, and habitat use. Using radiotelemetry, we tracked individual king rails among seasons, and established that at least a segment of this breeding population is resident. Mean (±SE) home range size was 19.8 ± 5.0 ha (95% kernel density) or 2.5 ± 0.9 (50% kernel density). We detected seasonal variation and sex differences in home range size and habitat use. In the nonbreeding season, resident male home ranges coincided essentially with their breeding territories. Overwintering males were more likely than females to be found in natural emergent marsh with a greater area of open water. Females tended to have larger home ranges than males during the nonbreeding season. We report for the first time the use of wooded natural marsh by overwintering females. Brood‐rearing king rails led their young considerable distances away from their nests (average maximum distance: ~600 ± 200 m) and used both wooded natural and impounded marsh. King rails moved between natural marsh and managed impoundments during all life stages, but the proximity of these habitat types particularly benefitted brood‐rearing parents seeking foraging areas with shallower water in proximity to cover. Our results demonstrate the importance of interspersion of habitat types to support resident breeders. Summer draining of impounded wetlands that are seasonally flooded for wintering waterfowl allows regrowth of vegetation and provides additional habitat at a critical time for wading birds.     

Fall movements of Red‐headed Woodpeckers in South Carolina

Fall migration of Red‐headed Woodpeckers (Melanerpes erythrocephalus) can be erratic, with departure rates, directions, and distances varying among populations and individuals. We report fall migration departure dates, rates, and routes, and the size of fall home ranges of 62 radio‐tagged Red‐headed Woodpeckers in western South Carolina. Rates of fall migration differed among years; all radio‐tagged woodpeckers migrated in 2005 (15 of 15), none (0 of 23) migrated in 2006, and 54.2% (13 of 24) migrated in 2007. Of 28 woodpeckers that left their breeding territories, we relocated eight either en route or on their fall home ranges. These woodpeckers migrated short distances (4.3–22.2 km) south along the floodplain forest of a large creek. The variable migration patterns we observed indicate that Red‐headed Woodpeckers may best be described as facultative migrants. We determined the home range sizes of 13 woodpeckers in both seasons, regardless of whether they migrated, and fall home ranges were smaller (mean = 1.12 ha) than summer home ranges (mean = 3.23 ha). Fall‐winter movements of Red‐headed Woodpeckers were concentrated on mast‐producing oak (Quercus spp.) trees, which may have restricted home range sizes. The partial migration we observed in 2007 suggests that factors other than mast crop variability may also influence migration patterns because woodpeckers that year responded to the same annual mast crop in different ways, with some migrating and some remaining on breeding season home ranges during the fall.     

Spatial ecology of bluetongue lizards (Tiliqua spp.) in the Australian wet–dry tropics

New technologies for quantifying animal locations enable us to document habitat‐selection patterns of cryptic taxa in extraordinary detail. Northern bluetongues (Tiliqua scincoides intermedia) and centralian bluetongues (Tiliqua multifasciata) are large heavy‐bodied scincid lizards that are broadly sympatric in the wet–dry tropics of north‐western Australia. We used data from GPS‐based radiotelemetry (n = 49 lizards, tracked for 2–121 days, total n = 61 640 locations) to examine the size, internal structure and overlap of lizard home ranges. Despite substantial habitat differences at our two study sites (semi‐arid and relatively pristine habitat at Keep River National Park, Northern Territory, vs. highly disturbed and fragmented flood plain habitat in an agricultural area near Kununurra, Western Australia), home ranges were similar between the two areas, and between the two species. Our radio‐tracked lizards continued to disperse into previously unused areas throughout the duration of the study, so that the total areas used by lizards continued to increase. Based on the minimum convex polygon method, total home ranges averaged 4 ha (range 2–12 ha), but only about two‐thirds of each home range was used intensively. Each home range had multiple core areas, and overlap of core as well as peripheral areas (especially with same‐sex conspecifics) was high at the disturbed (Western Australia) site where lizard densities were high. The concentration of lizard activity within small core areas, often used by multiple individuals, suggests that these heavily used sites are critical to lizard conservation. However, the lizards' infrequent long‐distance displacements also make them vulnerable to changes in the wider landscape mosaic. Because GPS‐based radiotelemetry can quantify habitat use at finer spatial and temporal scales than earlier technologies, it can provide a robust base for management of at‐risk fauna.     

Size and overlap of home range inCalomys musculinus (Muridae: Sigmodontinae)

Home range size and overlap ofCalomys musculinus (Thomas, 1913) was examined in relation to sex and breeding periods. The study was carried out in four 0.25 ha enclosures, in a natural pasture, between October 2002 and July 2003. The four enclosures functioned as independent populations and each was considered a replicate. The capture, mark and recapture method was used. Home range size and overlap inC. musculinus depended on sex and period. Home range size of males was always larger than that of females. Females showed a small degree of intra-sexual home range overlap during the breeding period. In general, male home ranges overlapped with females. We conclude that differences in home range size inC. musculinus is determined by sex and breeding period. Moreover, the degree of inter- and intra-sexual home range overlap during the breeding period suggests that both males and females ofC. musculinus use space differently. Females did not share their home range with other females, while males fully shared it with both sexes, and male spacing is influenced by the distribution of females. A promiscuous-polygynous mating system is suggested forC. musculinus.     

Home Range Size of Sympatric Squirrel Species Inhabiting a Lowland Dipterocarp Forest in Malaysia1

Home range sizes and spatial overlap of four sympatric squirrel species were investigated in a lowland dipterocarp forest in Malaysia using a radio‐tracking method. The population density of Callosciurus caniceps was highest and C. notatus was next highest, while C. nigrovittatus and Lariscus insignis were scarce. C. caniceps was larger than C. nigrovittatus and C. notatus while L. insignis was extremely small. For females, home range size was smaller in L. insignis than Callosciurus spp., which may support the body weight hypothesis: larger species have larger home ranges. Among the three Callosciurus species, female C. caniceps had the smallest home range. These differences were accounted for by habitat characteristics rather than by density or body weight; C. caniceps was dominant in bushy areas and used crowded small trees while C. notatus and C. nigrovittatus used large trees in the forest. In this study, home range size did not change seasonally; this differs from studies in temperate regions, possibly because food availability is much less variable among seasons in tropical rain forest. Home range overlap among heterospecific individuals was common but different species seemed to partition space by using different vertical levels of the forest. Consequently, the home range size and spatial overlap of sympatric squirrel species may be affected by habitat diversity in tropical rain forest.     

Age‐ and sex‐related differences in the spatial ecology of a dichromatic tropical python (Morelia viridis)

Abstract: Despite outnumbering their temperate counterparts, tropical snake species have been poorly studied. Yet, the few tropical species that have been studied show a variety of behavioural traits beyond those described in temperate species. Here we reveal both age and sexual differences in the movements of tropical green pythons (Morelia viridis: Pythonidae). We radio‐tracked 27 individuals (17 females and 10 males) for up to 18 months, locating individuals during both the day and night. The home range size for adult females (mean ± SE of 6.21 ± 1.85 ha) was correlated with snout–vent length. Neither adult males nor juveniles had a stable home range. Adult females had stable home ranges that overlapped considerably with those of other females and yellow individuals. Multiple radio‐tracked adult males passed through the territory of radio‐tracked adult females during the study. Females of all sizes were more likely to change position each day than males. There were no differences between the sexes or size categories in the distances moved in most months, although the variation in movement distances was higher in the dry season than during the wet season. In the wet season (January–March) movement distances increased and these were size‐ and sex‐related. This increased activity may be associated with mate searching. Males of M. viridis may maximize their rate of encountering mature females by roaming rather than maintaining a home range. Juvenile green pythons moved distances equal to adult snakes in most months despite their comparatively small size.     

Female striped mice (Rhabdomys pumilio) change their home ranges in response to seasonal variation in food availability

Animals may respond to seasonally changing environments withphysiological and behavioral strategies. Whereas migration isa behavioral strategy used by many taxa, it may not be an optionfor small mammals. However, small mammals can seasonally varythe area of habitat in which they are active. The striped mouseRhabdomys pumilio in the semiarid Succulent Karoo of South Africalives in a seasonal environment, characterized by hot, dry summerswith low food abundance and cold, wet winters, followed by highfood abundance in spring. We radio tracked a total of 28 femalesduring the 2004 dry season, the following breeding season inspring, and the following dry season in 2005 and tested theprediction that females shift their home ranges in relationto food availability. Females shifted their home ranges froman area characterized by evergreen succulent shrubs in the vicinityof a dry riverbed in the dry season to sandy areas that werecharacterized by new plant growth of annuals in spring. Homeranges during the breeding season in spring had a higher percentageof annuals than dry season home ranges measured in spring. Femalehome range size increased during the breeding season. We suggestthat female striped mice shift their home ranges seasonallyto gain access to protein-rich young plant material, which isimportant for breeding.     

Home range and territory of the Sardinian Warbler Sylvia melanocephala in Mediterranean shrubland

Capsule Singing territories were well separated.

Aims To examine the spatial distribution of Sardinian Warbler males during the breeding period in Mediterranean shrubland and, specifically, their territories, home ranges and spatial overlaps.

Methods We studied a 12-ha plot of Mediterranean shrubland in the 1997 to 1999 breeding seasons. Sardinian Warblers were captured using mist-nets, colour-ringed and their territories mapped. In 1999, seven breeding males were radiotracked in order to map home ranges.

Results The Sardinian Warbler had an average of 7.3 breeding pairs/10 ha in the study plot. The mean territory size was 8779 m² and the mean home range was 22 321 m². A positive relationship was found between the area of the home range and singing territory. Home ranges of males born in 1998 were about half the size of those of the oldest males. Paired males who moved with a female had smaller home ranges than those that were either unpaired or whose mate was incubating. The degree of home range overlap was high with some overlap between neighbouring territories. The estimate of home range area increased by 10% when the information generated by a mapping method was added and the estimated territory area increased by 31% when data generated by radiotracking were added. Transmitters remained attached to birds for an average of 9.63 ± 3.46 days (mean ± se).

Conclusions Singing territories were segregated to a considerable degree. In contrast, the wide overlaps among home ranges was best explained by the presence of food resources that the males exploit at the same time and also by the search for extra-pair copulation in nearby territories. We consider radiotracking in this species to be feasible and valid, with no evidence of negative effects on activity levels, weight or mortality.     

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.