Annual Home Range Size Research Articles

Cause-Specific Mortality and Survival of White-Tailed Deer Fawns in Southwestern Lower Michigan

Understanding white-tailed deer (Odocoileus virginianus) fawn survival is critical for managing herd dynamics and setting effective harvest regulations. We fitted white-tailed deer fawns with radiocollars during spring 2001 (n = 35) and 2002 (n = 40) to quantify cause-specific mortality, survival, and home-range size and composition in the southwestern Lower Peninsula of Michigan, USA. We monitored fawns a minimum of twice a week until they died, were censored, or the tracking period ended. Seventeen of 75 fawns died. The primary causes of mortality were legal hunting (n = 5) and deer–vehicle collisions (n = 5). Other causes included dehydration, bacterial infection, suspected coyote (Canis latrans) predation, drowning, and malnutrition. Survival probabilities for 2001 and 2002 radiocollared fawns to 30 days postcapture were 0.97 and 0.93, respectively. Capture-to-prehunt (127 days) fawn-survival probabilities were 0.91 for 2001 fawns and 0.90 for 2002 fawns. Posthunt (220 days) fawn survival probabilities were 0.76 for 2001 fawns and 0.85 for 2002 fawns. Annual estimated fawn-survival probabilities were 0.76 for 2001 and 0.75 for 2002. Mean annual home-range size for fawns was 75.36 ha. Habitat quality and land cover and use were potential factors that contributed to our high fawn survival. Our results can aid wildlife biologists in developing, refining, and validating deer population models as well as devising and balancing white-tailed deer population management decisions in an agroforested landscape.

Regulation of space use in a solitary felid: population density or prey availability?

Home range size in birds and mammals appears to be influenced by a number of factors including food availability, body mass and population density. However, few studies have convincingly shown population density to influence the extent of space use in a population of free-ranging carnivores without a corresponding increase in food availability. We investigated the relative effects of food availability, body weight and increased density on the size of adult bobcat, Lynx rufus, home ranges and core areas in Mississippi, U.S.A. during 1989–1997. We observed an increase in population density and a decrease in annual mean home range and core area sizes for males and females during this 9-year study. Population density explained 64% and 56% of the variation in home range size for males and females, respectively, whereas food availability and body weight failed to explain the observed reduction in bobcat home range size. Population density was also the most important variable explaining variation in core areas for both sexes, although food availability also appeared to contribute to variation, especially for females. We suggest that population density should be considered along with energy acquisition and metabolic factors such as food availability and body size when investigating variability in home range and core area sizes of mammals.

Movement patterns of Blanding's turtles (Emydoidea blandingii) in the suburban landscape of eastern Massachusetts

We studied Blanding's turtle Emydoideablandingii home range and seasonal movement patterns at 10 sites in suburban eastern Massachusetts during 2001 and 2002. Radio telemetry was used to track 51 turtles (31 females and 20 males) and home range was estimated during 4 seasonal activity periods usingthe 95% fixed kernel estimator. Sex, year, and site were not found to affect home range size due to the large amount of variationbetween and within individuals. There were significant differences in home range length between activity periods, with longest movementsoccurring during the period of 15 April to 31 May as animals moved to ephemeral wetlands. Mean annual home range size for Blanding's turtles was 22 ha, and mean home range length was 856 m. Animals frequently had annual home ranges that overlapped little from year to year, indicating that our calculations greatly underestimate the lifetime home range of an individual. Due to the large area needs of Blanding's turtles, and the diversified ownership of lands in eastern Massachusetts, numerous stakeholders will need to be involved to effectively protect viable populations for the foreseeable future.

Spatial organization and diet of the leopard cat (Prionailurus bengalensis) in north‐central Thailand

AbstractThe leopard cat Prionailurus bengalensis is a relatively common, small felid ranging throughout Asia. During the past 15 years the natural history of leopard cats has been the topic of five studies; however, the mean sample size of study animals has been low (x = 6.8, range 4–10). We report on the most comprehensive study of leopard cats to date. Between June 1999 and February 2003, 20 leopard cats (14 males and six females) were radio‐collared and tracked from 3 to 20 months in Phu Khieo Wildlife Sanctuary, Thailand. Spatial organization of the leopard cats was characterized as weakly territorial with similar intrasexual range sizes and minimal seasonal variation. Mean (±sd) annual home‐range (95% minimum convex polygon) size for males was 12.4 km2 (n= 1211 locations, ± 7.1, range 2.2–28.9), whereas females exhibited a mean home‐range size of 14 km2 (n= 470, ± 12.2, range 4.4–37.1). Core area (50% minimum convex polygon) averaged 2.0 km2, and the mean 1‐day movement was 1298 m (± 981, range 35–8653). Habitat use was generally in proportion to occurrence, and the mean activity (52%) was arrhythmic with crepuscular and nocturnal peaks. Analysis of scats indicated that murids dominated leopard cat diet.

Home Range and Habitat Use of Coyotes in an Area of Native Prairie, Farmland and CRP Fields

Abstract From 1999 to 2001 we monitored 12 coyotes (Canis latrans) in northwestern Texas to determine their home ranges and habitat use in a landscape interspersed with native prairie, farmland and Conservation Reserve Program (CRP) fields. Annual home range size was 10.1 km2 for residents and 84.5 km2 for transients. We determined habitat use at two spatial scales: within home ranges and within study area. Habitat use patterns were similar at both scales, as residents selected for native prairie and transients selected for CRP fields. Habitat use between residents and transients differed in both seasons, with residents selecting more native prairie, less farmland and less CRP (summer only) than transients. Habitat at natal den sites also differed from expected for residents, as most dens (8 of 10) were located in CRP fields. The CRP fields contained the only tall permanent vegetation on our study sites and appeared to provide important foraging habitat for transient coyotes, and denning habitat for resid...

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Spatial Ecology of Puerto Rican Boas (Epicrates inornatus) in a Hurricane Impacted Forest

ABSTRACTSpatial ecology of Puerto Rican boas (Epicrates inornatus, Boidae) was studied with radiotelemetry in a subtropical wet forest recovering from a major hurricane (7–9 yr previous) when Hurricane Georges struck. Different boas were studied during three periods relative to Hurricane Georges: before only; before and after; and after only. Mean daily movement per month increased throughout the three periods, indicating that the boas moved more after the storm than before. Radio‐tagged boas also became more visible to observers after the hurricane. Throughout the three periods, the sexes differed in movements, with males moving greater distances per move and moving more frequently than females. Males showed a bimodal peak of movement during April and June in contrast to the females’ July peak. Sexes did not differ in annual home range size, which had a median value of 8.5 ha (range = 2.0–105.5 ha, N = 18) for 95 percent adaptive kernal. Females spent more time on or below ground than did males, which were mostly arboreal. Trees used by boas had larger diameters and more vines than random trees. Hurricane winds that strip leaves, vines, and branches from trees may reduce cover for boas and limit access to arboreal sites, at least for several years until succession brings about recovery with increased vine growth. Boas were especially difficult to observe; telemetrically monitored boas were detected visually at an average of only 15 percent of their fix sites, indicating that the species is more abundant than generally perceived.RESUMENLa ecologia espacial de las boas Puertorriqueñas (Epicrates inornatus; Boidae) fue estudiada con radio telemetrfa en un bosque subtropical lluvioso, en recuperacion de un fuerte huracan (7–9 anos antes) cuando el Huracán Georges azotó la isla. Varias boas fueron estudiadas durante tres periodos relativos al Huracán Georges: antes, antes y después, y después del huracán. El desplazamiento diario promedio por mes se incrementó a lo largo de los tres periodos, indicando que las boas se desplazaron más después que antes de la tormenta. Las boas con radio transmisor eran más visibles a los observadores después del huracán. El desplazamiento de los sexos difirió a lo largo de los tres periodos, recorriendo los machos mayor distancia por movimiento y desplazándose con mayor frecuencia que las hembras. Los machos mostraron un desplazamiento bimodal, con picos en abril y junio, en contraste de las hembras donde el pico fue en julio. Los sexos no difirieron en el tamaño del territorio, el cual presenta una mediana de 8.5 ha (intervalo = 2.0–105.5 ha, N= 18) para el 95 por ciento adaptive kernal. Las hembras pasaron mayor tiempo encima o bajo tierra que los machos, los cuales eran principalmente arbóreos. Los árboles utilizados por las boas tenian un diámetro mayor y más lianas que árboles escogidos al azar. Los vientos huracanados que despojan a los árboles de sus hojas, lianas y ramas, pueden reducir la cobertura de las boas y limitar su acceso a ubicaciones arbóreas al menos por varies años hasta que la sucesión traiga consigo recuperación en incremento del crecimiento de lianas. Las boas estudiadas fueron especialmente dificiles de observar; boas seguidas con telemetria fueron detectadas visualmente en promedio en sólo el 15 por ciento de las veces buscadas, indicando que la especie posiblemente sea más abundante de lo que se percibe.

Seasonal variations of spatial behaviour in female Alpine ibex (Capra ibex ibex) in relation to climatic conditions and age

The spatial behaviour of female Alpine ibex Capra ibex ibex L. 1758, was analysed in Gran Paradiso National Park (Italy). Data were collected on 14 radiocollared females from September 2000 to August 2002, using radio-tracking and direct observations. Seasonal spatial behaviour was influenced by environmental conditions, in particular climatic factors. In the presence of thick snow cover, females significantly reduced winter home range sizes. Snow cover limited ibex mobility and reduced localization altitudes. Annual home range and winter home range sizes were inversely related to age. Temperature modified the use of space by females during summer. During the hottest summer females moved over larger ranges at higher altitudes. Annual home range sizes (mean 186.2 ha ± 71.7 in 2000 and 182.2 ha ± 70.0 in 2001) and seasonal home range sizes were significantly smaller than those of reintroduced populations, moreover they were smaller that those of males calculated in a close study area in Gran Paradiso National Park.

Annual and seasonal habitat use of Columbian black-tailed deer in urban Vancouver, Washington

We investigated habitat use of Columbian black-tailed deer in urban Vancouver, Clark County, Washington, at 3 spatial scales: (1) placement of the annual home range within the landscape mosaic, (2) annual and seasonal locations of deer within the annual home range, and (3) short-term use of critical habitats (fawning areas) within seasonal ranges. Annual home range sizes of deer were 162 ha (SD = 133; 95% minimum convex polygon; MCP) and 266 ha (SD = 228; 95% adaptive kernel; AK) for does, and 756 ha (SD = 290; MCP) and 1,235 ha (SD = 382; AK) for bucks. Home range composition of does did not differ from the study area; home ranges of bucks contained more Natural ecological land-use cover types (ELUs) than did the study area. Within home ranges, both does and bucks used Natural ELUs more often than expected by their occurrence in the home range, both annually and seasonally. During the fawning season, does were also found in Natural ELUs more often than expected. Clark County-designated habitat corridors differed from both the study area and deer home ranges in habitat composition, primarily by containing more Natural and other undeveloped ELUs. Deer were located in habitat corridors more than expected. Deer in urban areas appear to use undeveloped habitat types for security. Management that maintains Natural ELUs, such as establishment of wildlife corridors, can provide important habitat components for black-tailed deer in urban habitats.

Spatial Ecology of Puerto Rican Boas (Epicrates inornatus) in a Hurricane Impacted Forest1

Spatial ecology of Puerto Rican boas (Epicrates inornatus, Boidae) was studied with radiotelemetry in a subtropical wet forest recovering from a major hurricane (7–9 yr previous) when Hurricane Georges struck. Different boas were studied during three periods relative to Hurricane Georges: before only; before and after; and after only. Mean daily movement per month increased throughout the three periods, indicating that the boas moved more after the storm than before. Radio-tagged boas also became more visible to observers after the hurricane. Throughout the three periods, the sexes differed in movements, with males moving greater distances per move and moving more frequently than females. Males showed a bimodal peak of movement during April and June in contrast to the females' July peak. Sexes did not differ in annual home range size, which had a median value of 8.5 ha (range = 2.0–105.5 ha, N = 18) for 95 percent adaptive kernal. Females spent more time on or below ground than did males, which were mostly arboreal. Trees used by boas had larger diameters and more vines than random trees. Hurricane winds that strip leaves, vines, and branches from trees may reduce cover for boas and limit access to arboreal sites, at least for several years until succession brings about recovery with increased vine growth. Boas were especially difficult to observe; telemetrically monitored boas were detected visually at an average of only 15 percent of their fix sites, indicating that the species is more abundant than generally perceived.

HOME RANGES OF SYMPATRIC BLACK AND TURKEY VULTURES IN SOUTH CAROLINA

Abstract We examined home-range characteristics of seven Black Vultures (Coragyps atratus) and four Turkey Vultures (Cathartes aura) at the Savannah River Site, South Carolina. Birds were captured at their primary roost and tracked via aerial telemetry from 11 February 2002 through 29 January 2003. Mean annual home-range sizes (95% fixed kernel) for Black and Turkey Vultures were 12 399 ± 5199 ha [SE] and 34 053 ± 8567 ha, respectively. Black Vultures concentrated their movements around the primary roost, whereas Turkey Vultures demonstrated less site fidelity. Home-range sizes and time spent soaring for both species were much greater than reported for vultures residing in an agricultural landscape. We suggest that food resources at the heavily forested Savannah River Site were fewer and less predictable than in agricultural landscapes, requiring larger home ranges and increased time spent foraging. Rangos de Hogar de los Buitres Simpatricos Coragyps atratus y Cathartes aura en Carolina del Sur Resumen. E...

Space-Use Strategy Is an Important Determinant of PCB Concentrations in Female Polar Bears in the Barents Sea

Space-use was examined in 54 female polar bears (Ursus maritimus) from Svalbard and the Barents Sea that were collared with satellite transmitters to provide information on their spatial positions and annual home range sizes. Plasma samples from the same animals were analyzed for concentrations of six relevant PCB congeners (PCB-99, -153, -156, -180, -194, and -118). Factors related to space-use strategy (such as home range size; annual, spring, and winter longitudinal position; and spring and summer latitudinal position) were important determinants of PCB concentrations in plasma. In addition, reproductive status of the polar bears and plasma lipid content affected PCB concentrations. Among the tested variables, annual home range size was the variable that affected sigmaPCB5 (sum of PCB-99, -153, -156, -180, and -194) to the largest degree (r2 = 0.22). We propose that the positive effect of home range size on sigmaPCB5 in female polar bears is related to the higher energetic costs required to occupy large home range sizes as compared to small home range sizes. Polar bears with large home range sizes would need to consume more prey than bears with small home range sizes, and increased feeding without a change in elimination of persistent compounds can explain their higher sigmaPCB5 concentrations. Polar bears with large home range sizes were also more pelagic, inhabiting areas further east, closer to the ice-edge zone than animals with small home range sizes. Thus, prey choice associated with a pelagic space-use strategy may also explain the higher sigmaPCB5 in polar bears with large home range sizes.

PATTERNS OF MOVEMENT AND BURROW USE IN A POPULATION OF GOPHER TORTOISES (GOPHERUS POLYPHEMUS)

We investigated movement and burrow use patterns from May 1997 through May 1998 in a gopher tortoise population (n 5 123) within a 100-ha study site of high quality (old trees, ground cover intact, growing-season fire regime) longleaf pine-wiregrass habitat located in Baker County, Georgia, USA. Telemetered females moved more frequently in summer months (June-October) but traveled longer distances in September than during other months of the 1997 active season. Males exhibited a peak in movement during August and September 1997 that corresponded with mating activity. The longest distance moved between tracking locations did not differ between males and females, but mean distance per move, number of burrows used, and annual home range size were greater in males than in females. The maximum distance moved by an individual during an active season was negatively correlated with female body size but not male body size. No such relationship was found between body size and number of burrows used by either females or males. Similarly, no relationship was found between body size and annual home range area of adult females and males. Our study provides the most complete estimate of annual home range size of gopher tortoises. Because these data describe movements in an area that retains features of the ancestral habitat, these estimates are the best available for designing reserve areas for this threatened species.

Spatial behaviour of adult male Alpine ibexCapra ibex ibex in the Gran Paradiso National Park, Italy

During a two year preliminary study, the spatial organization of a group of male Alpine ibexCapra ibex ibex Linnaeus, 1758 was examined in the Gran Paradiso National Park, Western Italian Alps, Italy. From December 1995 to January 1998 we measured annual, seasonal home range and home range during the rut, plus altitudinal migration of 13 radio-collared adult Alpine ibex. The small annual home range size showed a traditional use of space, confirmed by the high overlapping values between home ranges of consecutive years: the ibex used the same places from year to year. This was also true during periods of rut. Home ranges closely overlapped in consecutive ruts, while their size changed from winter to winter. Snow cover limited the movements of the ibex; winter and spring home ranges were smaller than those in summer and autumn. Mean vertical movement patterns were similar in the two years, showing the highest values in summer and the lowest in spring. Space use was never proportional to availability for each altitudinal range.

HABITAT USE, HOME RANGES, AND SURVIVAL OF SWIFT FOXES IN A FRAGMENTED LANDSCAPE: CONSERVATION IMPLICATIONS

Habitat loss might be one of the primary reasons for the decline of the swift fox (Vulpes velox) in the western Great Plains of North America. From 1998 to 2001, we monitored 42 swift foxes in a landscape interspersed with native short-grass prairies, nonnative grasslands enrolled in the Conservation Reserve Program, irrigated agricultural fields, and dryland agricultural fields. Survival estimates ranged from 0.52 to 0.66 for both adults and juveniles, and the primary causes of death were vehicle collisions (42% deaths) and coyote (Canis latrans) predation (33%). Annual home-range size was similar for males and females (10.8 and 10.5 km 2 , respectively). Within the study area, swift foxes selected only shortgrass prairies and had lower-than-expected use or complete avoidance of all other habitat types. Our results indicate swift foxes are more specialized in habitat selection than other North American canids; thus, protection of native short-grass prairies might be necessary for their long-term existence.

Range size and seasonal movement for female woodland caribou in the boreal forest of northeastern Ontario

A preliminary examination was conducted of range size and distribution of female woodland caribou (Rangifer tarandus caribou) in northeastern Ontario. Annual and seasonal ranges were calculated using satellite telemetry data collected for 30 female caribou between 1998 and 2001. The mean annual home range size of collared females was 4026 km2. Seasonal ranges varied in size depending on time of year (P&amp;lt;0.05). Calving and summer ranges were significantly smaller than autumn and late winter ranges. Early winter ranges were significantly larger than calving ranges and smaller than late winter ranges. Overall, range sizes of female woodland caribou in northeastern Ontario were larger than those reported for caribou in other Boreal Forest regions across Canada.

Home range and frugivory patterns of mountain gorillas in Bwindi Impenetrable National Park, Uganda

Mountain, western, and Grauer's gorillas exhibit broad differences in ecological patterns with western gorillas eating more fruit and having larger home ranges than their largely folivorous counterparts in the Virunga Volcanoes. We studied the home range and frugivory patterns of one group of Gorilla beringei beringei in the little-studied population of Bwindi Impenetrable National Park, Uganda, to compare with other populations and to investigate whether there was any relationship between patterns of frugivory and home range size. During the 3-year study, the gorillas ate 16 species of fruit on 27% of observation days. There was high variability in frugivory among the 3 years and no consistent seasonal pattern. Annual home range size was ca. 21 km2 for Years 1 and 2, and it increased dramatically to 40 km2 in Year 3. Home range size varied considerable between months and seasons, but there is no clear relationship between occurrence of fruit-eating and home range size. The group exhibited more fruit-eating and a larger home range size those ofthe gorillas in the Virunga Volcanoes. Their home range size is comparable to that of western gorillas, though Bwindi gorillas consumed less fruit. Home range size and utilization by all gorillas probably depends on a complex relationship between the distribution and abundance of both fruit and herbaceous vegetation and social factors such as male mating tactics.

Variation in home range size of female Fallow Deer inhabiting a sub-mediterranean habitat

From 1997 to 2000 13 female Fallow Deer (Dama dama) were monitored using telemetry in the San Rossore Estate (Tuscany, central Italy) to determine home range size and patterns of range development. Mean annual home range size was estimated using the Minimum Convex Polygon method (95%) over 532.9 ± 226.8 ha and the Kernel method (95%) over 426.8 ± 151.2 ha. These home range sizes are larger than those previously reported in the literature : San Rossore is an environment characterized by a fragmented distribution of trophic resources and this may lead to an increase in range size. The average size of home ranges differed considerably between seasons, the smallest ranges being found during summer, averaging 140.9 ± 112.5 ha (MCP 95%) and 126.0 ± 102.4 ha (Kernel 95%). The autumn and spring ranges amounted to twice as much, with an average size of 348.5 ± 170.5 ha and 304.0 ± 175.8 ha, respectively, using MCP 95%, and 380.5 ± 178.1 ha and 292.9 ± 177.3 ha, using Kernel 95%. Winter ranges were slightly larger than summer ones averaging 184.5 ± 119.8 ha (MCP 95%), and 195.2 ± 122.1 ha (Kernel 95%). This study showed that ecological factors and the presence of young reduce home range size during the May-August period. Food distribution and the rutting season during autumn, and green-up during spring, caused an increase in home range size.

Home range size and reproduction of female roe deer re-introduced into a Mediterranean habitat

From 1995 to 1997, 52 males and 52 females, which had been captured in the Forest ofTrois Fontaines (Northeast of France), were re-introduced into thePetit Luberon state forest (South of France). Among them 49 females (21 young [ 1 year old]) were monitored by radio-tracking. The mean annual home-range sizes (mean 95% MCP = 157 ha) were larger than those estimated in more temperate forests, but were smaller than in cultivated plains. In spring and summer, repeated visual observations allowed us to study the reproduction of the monitored docs and the summer survival of their fawns. The mean number of fawns per adult female was 1.18 (SE = 0.13) and the mean number of fawns per doe with young was 1.59 (SE = 0.09). The fecundity of the does and the summer survival of their fawns were similar in our study area and inTrois-Fontaines (their area of origin).

Swift fox (Vulpes velox) home-range dispersion patterns in southeastern Wyoming

We monitored dispersion patterns of swift foxes (Vulpes velox) for 3 years in shrub-grassland habitats on the margin of the species' geographic range near Medicine Bow, Wyoming. Annual home-range size was 18.6 ± 1.6 km2 (mean ± SE, n = 13) and was similar to home-range estimates reported in other studies conducted within grassland habitats in other portions of the species' geographic range. Male home ranges were larger than those of their mates during pup-rearing periods (P &lt; 0.04) but were similar in size during the dispersal period. The home ranges of both sexes were smallest during the pup-rearing period. The degree of home-range overlap for mates (biological periods combined) was high (range = 27.4–100%, mean ± SE = 70.8 ± 0.03%, n = 26 pairs) but was minimal between adjacent pairs (range = 0.2–36%, mean ± SE = 11.9 ± 2.4%, n = 10 pairs), suggesting territorial behavior. Occupied home ranges were distributed similarly each year despite one or both pair members often being new. Swift fox home-range size varied seasonally, and home-range dispersion patterns appeared to be influenced by the presence of other fox pairs and the recent use of an area by other swift foxes.