Differences In Home Range Size Research Articles

SEX DIFFERENCES IN SPACE USE OF BREEDING COMMON RAVENS IN WESTERN MARIN COUNTY, CALIFORNIA

We estimated core areas and home-range sizes and evaluated sex differences in home-range size, seasonal variation in movements, and space use for breeding Common Ravens (Corvus corax) in western Marin County, California. There were no significant interannual differences in average core area or average home-range size for either sex, although there were small-scale shifts in home-range use for 67% of females and 63% of males. There was no significant difference in home-range size between the sexes. Home-range size was positively correlated with distance to food source. Ravens traveled shorter distances from the nest during the incubation + nestling stage compared to other stages of the breeding season. Core areas were centered around nest sites and food sources, with significantly aggregated locations for 83% and 100% of females in 2000 and 2001, respectively. Males were more variable in their use of space, with significantly aggregated locations for 38% and 44% of males in 2000 and 2001, respectively. Individual variation in home-range size, movements, and space use was likely due to differences in the distribution of important food sources in the area. Diferencias Sexuales en la Utilización del Espacio en Corvus corax en el Oeste del Condado Marin, California Resumen. Estimamos los tamaños del área núcleo y rango de hogar y evaluamos las diferencias entre sexos en el tamaño del rango de hogar, variaciones estacionales de los movimientos y utilización del espacio en Corvus corax en el oeste del condado Marin, California. No hubo diferencias interanuales significativas en el área núcleo promedio ni en el rango de hogar promedio para ninguno de los sexos, aunque para el 67% de las hembras y el 63% de los machos hubo cambios de pequeña escala en el uso del rango de hogar. No hubo diferencias significativas en el tamaño de los rangos de hogar entre sexos. El tamaño del rango de hogar estuvo positivamente correlacionado con la distancia a la fuente de alimento. Los cuervos viajaron distancias más cortas desde el nido durante los períodos de incubación y de cría de polluelos en comparación con otros períodos durante la época reproductiva. Las áreas núcleo se centraron en los sitios de nidificación y las fuentes de alimento, con posiciones significativamente agregadas para el 83% y 100% de las hembras en 2000 y 2001, respectivamente. Los machos presentaron mayor variabilidad en la utilización del espacio, con posiciones significativamente agregadas para un 38% y 44% de los machos en el 2000 y 2001, respectivamente. Las variaciones individuales en el tamaño de los ámbitos de hogar, movimientos y uso del espacio fueron probablemente dadas por las diferencias en la distribución de los recursos alimenticios importantes en el área.

The effect of establishing native woodland on habitat selection and ranging of moorland mountain hares (Lepus timidus), a flexible forager

Mountain hares Lepus timidus L. typify species that occupy a broad geographic range and have flexible foraging and nutritional strategies. Such species may show a range of responses to habitat modification. This study aimed to provide a basis for prediction of the impact of mountain hares on woodland establishment, and of woodland establishment on mountain hare distribution. The selection of and the extent of incorporation of new woodland into the home range of mountain hares was investigated in an area where Scots pine Pinus sylvestris L. woodland was establishing within their usual habitat in Britain, upland heather moorland. Seasonal home, day and night‐range sizes of radio‐tracked mountain hares were determined using the multinuclear probability polygon technique and analysed using residual maximum likelihood (REML). Habitat selection was analysed using compositional analysis. Three main habitat types were available to hares: heather moorland with trees, heather moorland and grassland‐mire. Mean home‐range size of mountain hares in summer was 10.3 ha and in winter 9.6 ha. There were no significant seasonal or sex differences in home‐range size. Females selected grassland‐mire habitat in summer and showed no strong selection for any habitat in winter. Males selected heather moorland in both summer and winter. Heather moorland with trees was not selected preferentially by mountain hares of either sex in summer or winter. The absence of selection for areas of newly establishing‐Scots pine woodland suggests that any browsing damage to trees by hares is most likely to be a function of the local abundance of mountain hares, rather than a result of active preference of hares for the modified habitat.

Does availability of resources influence grazing strategies in female Svalbard reindeer?

Foraging strategies and range use in wild female Svalbard reindeer (Rangifer tarandus platyrhynchus) were studied in two areas where the historical grazing pressure differed. We mapped vegetation where the reindeer were seen grazing, and related forage availability to characteristics such as home range size, activity budgets and reproductive status. There were significant differences in quantity of forage available between the two areas and the utilization of vegetation types differed between the sites. However, we found no difference in home range size between the two sites, and individual home range sizes were not related to forage quantity, possibly a result of a skewed and small sample size. Even though significant differences in availability of plant species and groups were found, no variation in home range size was found between reproductive and non-reproductive females on Brøggerhalvøya. Neither did we find any differences between areas or between reproductive groups within or between areas in how female reindeer allocated use of time, or in number of steps taken. However, a significant three way interaction indicated that some variance existed between reproductive groups within or between areas, but we do not conclude that this indicate different grazing strategies. Thus, even though variation in the duration of previous grazing has evidently resulted in rather different foraging conditions in our two areas, we detected no differences in present-day foraging behaviour. Thus, our analyses suggest no relationship or feedback between past grazing and current foraging behaviour in these reindeer.

Home-range size, habitat use, and reproduction of the Ivory-billed Woodcreeper (Xiphorhynchus flavigaster) in dry forest of western Mexico

Abstract From March 1999 to August 2000, we used mist-netting, point counts, and radio-tracking to study habitat use, area requirements, and breeding of the Ivory-billed Woodcreeper Xiphorhynchus flavigaster in the tropical deciduous and semi-deciduous forest (arroyo forest) of the Chamela-Cuixmala Biosphere Reserve, western Mexico. The Ivory-billed Woodcreeper was a common, year-round resident. Breeding commenced at the end of the dry season (May) and continued during the rainy season through August. Our observations suggested that only the female builds the nest, incubates, and feeds nestlings. Ivory-billed Woodcreepers commonly foraged alone, but sometimes joined mixed-species flocks that passed through their territories, occasionally following army ant swarms. Home-range size varied from 6–36 ha, although most birds' home range was 15 ha or less. We did not find differences in home range size or mobility between the dry and rainy seasons, and we did not find a correlation between the size of the home ...

Tamanho da área de vida e padrão de uso do espaço em grupos de sagüis, Callithrix jacchus (Linnaeus) (Primates, Callitrichidae)

The influence of abundance and distribution of fruits and gums resources in home range size and pattern of range use were investigated in Callithrix jacchus. From October 1996 to January 1998 two groups (QT and PB) that lived in a National Forest/IBAMA-RN in northeastern Brazil (6o5'S, 35o12'W), were observed once a week by instantaneous scan sampling. The frequency of quadrant's visit in the home range was recorded at five minute intervals. Trees used for feeding on fruits and/or gum by the study groups were marked with flagging tape and numbered. Samples of the food items were collected for identification. Data on the temporal variation in fruits abundance was based on the monthly phenological observations of the marked trees. Study groups showed small home range size (QT: 2.4 ha and PB: 0.7 ha). No significant differences in home range size between dry and wet months were found, but groups showed a tendency to broadened the range use in the wet months. This revealed a behavioral strategy which marmosets exploited more gums face to decreased in fruits abundance. The abundance and distribution in clusters of fruits and gums resources influenced the pattern of range use and home range size.

Home ranges of sympatric red-necked wallabies, red-bellied pademelons and common brushtail possums in a temperate eucalypt forestry environment.

We investigated home ranges of sympatric red-necked (or Bennett?s) wallabies Macropus rufogriseus rufogriseus, red-bellied pademelons Thylogale billardierii and common brushtail possums Trichosurus vulpecula fuliginosus within a forestry environment in north-west Tasmania. Six indiviuals of each species were radio-tracked between 7 and 11 months. Nocturnal and diurnal data were used to estimate Minimum Convex Polygon (MCP) home range, 95% fixed-Kernel (KE) home range and 50% KE core area. Home ranges (mean � s.e.) were as follows: M. r. rufogriseus MCP = 61 � 12 ha, KE = 41 � 3 ha; T. billardierii MCP = 22 � 5 ha, KE = 16 � 3 ha; and Tr. v. fuliginosus MCP = 39 � 8 ha, KE = 17 � 3 ha. M. r. rufogriseus had larger MCP home ranges than T. billardierii (P < 0.05), and larger KE home ranges and core areas than both T. billardierii and Tr. v. fuliginosus (P < 0.05), which reflected their larger body mass. Inter-sexual comparisons within the sexually dimorphic macropods showed that M. r. rufogriseus males had significantly larger MCP and KE home ranges and core areas than females (P < 0.05), and T. billardierii males tended to have a larger KE home ranges than females (P = 0.08). No inter-sexual difference in home range size was detected for Tr. v. fuliginosus.

Seasonal changes in home-range area and habitat use by the agile wallaby (Macropus agilis)

Radio-tagged male and female agile wallabies were tracked in the wet and dry seasons at a site in Darwin, Northern Territory, and home ranges estimated using a kernel-based estimator. Home-range size (95% contour) was larger in the dry season, when food quality was poorer, and males had larger home ranges than females. Core range size (55% contour) did not differ between seasons or sexes. Average male and female home-range sizes in the wet season were 16.6 ha and 11.3 ha respectively. Wet-season core range sizes were 4.8 ha and 3.2 ha respectively. Average male and female home-range sizes in the dry season were 24.6 ha and 15.3 ha respectively, and dry-season core range sizes were 5.1 ha and 4.0 ha respectively. Home-range size for both sexes varied in the two seasons; the smallest and largest female home ranges were 6.3 ha and 24.0 ha respectively, while male home-range size varied from 7.6 ha to 38.2 ha. Seasonal differences in home-range size can be attributed to expansion of night-time foraging areas in the dry season when good-quality food resources were in short supply. Habitat use also differed between seasons. In the dry season more fixes were located in forest areas, particularly in the evening, when wallabies foraged in forest areas for alternate food resources including browse, leaf litter, flowers and fruits of rainforest tree and shrub species. In the wet season, wallabies emerged from day-time resting areas earlier in the afternoon and therefore more wallabies were located in open areas grazing on high-quality herbage in the evening.

Home-range size and habitat selection by American marten (Martes americana) in Labrador

Variation in home-range size can be related to different factors at different spatial scales. This study examined the patterns of home-range size and habitat selection of American marten (Martes americana) in southeastern Labrador, a region of extensive and pristine forests. Over 1.5 years, we monitored 28 radio-collared marten and compared the availability of habitat types with their use. Marten avoided areas with low productivity and low canopy cover (<20%) but showed no selection for tree species composition or cover among more productive forests. Mean home ranges for both sexes (males, 45.0 km2; females, 27.6 km2) were exceptionally large, more than double the largest values previously recorded for the species. We analyzed variation in home-range size at two scales: within our study population and, using data from the literature, among populations across the species range in relation to temperature, snow cover, and body size. Within our population, home-range area was positively related to the proportion of bog and less productive, scrub forests in the home range. Among populations, differences in home-range size were not significantly related to any of the tested factors.

Factors affecting home range size and overlap in Calomys venustus (Muridae: Sigmodontinae) in Argentine agroecosystems

Summary In this study, information concerning home range size and overlap of Calomys venustus (Thomas, 1894), in relation to sex, population size, and breeding periods is provided. The present study was carried out on a railway bank in southern Cordoba Province (Argentina), between October 1994 and September 1997, using the capture-mark-recapture method. Home range size in C. venustus depended on breeding period and population size, and was independent of sex. The degree of home range overlap was dependent on breeding and non-breeding periods and overlap type (intra- or intersexual), but was independent of population density. During the breeding period, females showed a small degree of intrasexual home range overlap. In general, male home ranges largely overlapped with females. The conclusion is that differences in home range size of C. venustus could be determined by season and population size. Moreover, the degree of inter- and intrasexual home range overlap during the breeding period suggested that males and females of C. venustus 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 female distribution.

The demographic response of bank-dwelling beavers to flow regulation: a comparison on the Green and Yampa rivers

We assessed the effects of flow regulation on the demography of beavers (Castor canadensis) by comparing the density, home-range size, and body size of bank-dwelling beavers on two sixth-order alluvial river systems, the flow-regulated Green River and the free-flowing Yampa River, from 1997 to 2000. Flow regulation on the Green River has altered fluvial geomorphic processes, influencing the availability of willow and cottonwood, which, in turn, has influenced the demography of beavers. Beaver density was higher on the Green River (0.5–0.6 colonies per kilometre of river) than on the Yampa River (0.35 colonies per kilometre of river). Adult and subadult beavers on the Green River were in better condition, as indicated by larger body mass and tail size. There was no detectable difference in home-range size, though there were areas on the Yampa River that no beavers used. We attribute the improved habitat quality on the Green River to a greater availability of willow. We suggest that the sandy flats and sandbars that form during base flows and the ice cover that forms over winter on the Yampa River increase the energy expended by the beavers to obtain food and increase predation risk and thus lowers the availability of woody forage.

Are Female Voles Food Limited? Effects of Endophyte-infected Tall Fescue on Home Range Size in Female Prairie Voles (Microtus ochrogaster)

Abstract Space use patterns of female voles may or may not be related to quality and quantity of food available. We examined the relationship between food quality and home range size in female prairie voles (Microtus ochrogaster) by radiotracking voles on grids of tall fescue (Festuca arundinacea). Four grids were infected with a fungal endophyte (Neotyphodium coenophialum) while three grids of uninfected fescue served as references. This endophyte is known to lower food quality for mammalian herbivores, affecting growth rates and reproductive success. We predicted that home range sizes would be larger on endophyte-infected grids if range size is affected by access to food resources. Conversely, if space use is unrelated to food availability, changes in food quality should not change the home range size of female voles. We found no difference in home range size of voles on endophyte-infected and uninfected grids. Our results indicate that patterns of space use in female meadow voles may be driven by facto...

Movement Patterns of Adult Male Ovenbirds During the Post-Fledging Period in Fragmented and Forested Boreal Landscapes

Abstract Movement of forest songbirds among isolated forest patches following breeding represents an important but poorly understood component of landscape ecology and metapopulation theory. Using radio-telemetry, we followed 44 male Ovenbirds (Seiurus aurocapillus) during the post-fledging period to determine if movement patterns differed in landscapes dominated by agriculture versus those dominated by forest. No differences in home-range size, mean distance moved per day, or maximum distance moved were observed for males captured in a forested landscape vs. those captured in forest fragments in an agriculturally dominated landscape. Male Ovenbirds observed with young moved less than males without young and rarely crossed open gaps. Individuals that failed to breed moved more extensively than successful breeders, possibly in an effort to find new territories for use in future breeding seasons.

Home Range and Movements of the Bog Turtle (Clemmys muhlenbergii) in Maryland

We studied the home ranges and movements of 50 bog turtles (Clemmys muhlenbergii) at two sites in Harford County, Maryland, from April 1996 to August 1997. These sites differ in size, land use, and stage of vegetative succession. One site (HA406) was intensively studied 17 years ago. Using radiotelemetry, we located turtles two times a week during the active season. The 95% Adaptive Kernel home range esti- mator was used to determine home ranges. Individual turtle home ranges varied from 0.003 ha to 3.12 ha with considerable variation between sites and years. There were no significant differences in home range size or movements between sexes or seasons (mating vs. postmating), although males had larger home ranges during the mating season. Many turtles at site HA406 had home ranges far larger than the average home range reported in the earlier study. An expansion in turtle home ranges may suggest a decrease in site quality resulting from invasion of multiflora rose. Some turtles moved out of their wetlands and across barriers, a finding that demonstrates the importance of appropriate habitat in corridors that connect popu- lations.

MOVEMENT PATTERNS OF ADULT MALE OVENBIRDS DURING THE POST-FLEDGING PERIOD IN FRAGMENTED AND FORESTED BOREAL LANDSCAPES1

Abstract Movement of forest songbirds among isolated forest patches following breeding represents an important but poorly understood component of landscape ecology and metapopulation theory. Using radio-telemetry, we followed 44 male Ovenbirds (Seiurus aurocapillus) during the post-fledging period to determine if movement patterns differed in landscapes dominated by agriculture versus those dominated by forest. No differences in home-range size, mean distance moved per day, or maximum distance moved were observed for males captured in a forested landscape vs. those captured in forest fragments in an agriculturally dominated landscape. Male Ovenbirds observed with young moved less than males without young and rarely crossed open gaps. Individuals that failed to breed moved more extensively than successful breeders, possibly in an effort to find new territories for use in future breeding seasons.

Female home range size and the evolution of social organization in macropod marsupials

Summary1. Traditional explanations for interspecific variation in home range size are based almost exclusively on analysis of northern hemisphere eutherian mammals. These suggest that variation in body size is the most important factor, while climate and diet are less important. The generality of these explanations is tested using a novel database on macropod marsupials (kangaroos and allies).2. We found a 490‐fold difference in home range size and a 50‐fold difference in body weight amongst macropods. In agreement with studies on eutherians, female home range size was strongly correlated with body weight.3. However, unlike the pattern in eutherians, climate was more strongly associated with home range size than was body weight: annual rainfall explained more than half of the variation, while group size (6%) and population density (8%) were minor explanatory variables, and female body weight explained no further variation.4. When we used a phylogeny‐based comparative method, annual rainfall explained 32% of the variation and body size a further 16%.5. Sex differences in home range size were not explained by body size dimorphism, but were strongly related to rainfall and less strongly related to the degree of female home range overlap. Species with large sex differences in home range size lived in high‐rainfall habitats where female ranges were small.6. We suggest that climate has been a key factor in social evolution of macropods. In species inhabiting productive habitats, small female home ranges allow males to overlap with more females by increasing home range size. Males often compete for females by searching widely. In less productive habitats, males cannot further increase or defend their already large home ranges, resulting in similar‐sized ranges in both sexes. Where female home range overlap is high, males need not increase home ranges as much, but this effect is secondary to that of climate.7. In agreement with the theory that competitive searching by males is not necessarily related to body size, species with extreme size dimorphism had no sex difference in home range size, and species with extreme home range differences between the sexes showed no particular pattern of dimorphism.8. Variation among macropod species in home range size and social organization is more closely correlated with variation in habitat productivity, and is less related to body size, diet, density and group size, than predicted by eutherian‐based explanations.

HOME RANGE OF THE SOUTHERN BLOSSOM BAT,SYCONYCTERIS AUSTRALIS,IN PAPUA NEW GUINEA

Southern blossom bats, Syconycteris australis (Pteropodidae), were followed by radiotelemetry in lowland rainforest in Kau Wildlife Area, Madang Province, Papua New Guinea. Eleven individuals were monitored ≤31 days. Based on 706 radiotelemetry positions, home ranges of 11 bats were 2.7–13.6 ha. There were no significant differences in home-range sizes between sex or age classes, but there was individual overlap of the home ranges of these bats. Long axes of home ranges were 263–725 m. During each night, bats visited most parts of their home ranges; however, activity was concentrated in core-use areas representing 19–33% of the home range and containing ≥1 food patches. During the day, S. australis roosted in the foliage of trees. Bats showed fidelity to a day-roost area (0.4–10.8% of home range) but not to a single roost tree. Day-roost areas monitored within a given year showed virtually no overlap.

Space Use of Killdeer at a Great Basin Breeding Area

Wetland conservation efforts require knowledge of space use by a diversity of waterbirds. However, determining space use of animals requires intensive monitoring of individual organisms. Often, activity patterns during much of the annual cycle are neglected in analyses of home range and habitat use. From 1995-97, we monitored space use in a population of individually marked killdeer (Charadrius vociferus) that breed, and reside for a number of additional months each year, in the western Great Basin. We used linear distance measures and home range-area estimates, derived by fixed-kernel methods, to examine patterns of space use of adults prior to, during, and following nesting. Overall, killdeer used a local area of approximately 6 ha. Birds remained closer to nests while tending eggs than either before or after nesting, although extensive movements away from the nest were observed during all time periods. Females tended to move farther from nests than did males. Birds nesting farther from water bodies were generally observed at greater distances from nests than those nesting closer to shorelines during all time periods. Twenty-seven percent of individuals were observed greater than 1 km from nest locations, particularly during postnesting periods. During nesting periods, males were less likely to be observed at longer distances from nests than were females. There were no differences in home range size based upon sex, time period, or distance from water. We suggest that home range size may not always accurately measure differences in space use and that multiple measures, including distance from nests, should be considered. Understanding the sedentary nature of killdeer during much of the annual cycle and their intense use of local areas is important for making management decisions. Coupled with data on other shorebird species, this information also has broader implications for management of wetland systems by indicating large scale spatial and habitat requirements and the connectivity of geographically distinct habitat patches.

Home Range of Desert Mule Deer: Testing the Body-Size and Habitat-Productivity Hypotheses

The body-size hypothesis of home range predicts that, given constant home range productivity, larger animals with higher absolute metabolic requirements use larger home ranges to meet their metabolic needs. This relationship is well supported across a wide range of mammals and often has been invoked to explain differences in home range size between sexes that differ in body size However, the body-size hypothesis has rarely been tested within a species A corollary to this hypothesis states that for a given mass, animals in areas of low habitat productivity should have home ranges larger than those in productive habitat. To test these 2 hypotheses, we radiomonitored desert male deer (Odocoileus hemionus crooki) for 2 vears insouthwest Texas to determine the effects of sex, mass, and habitat productivity on annual home range size, Although male mule deer had more massive bodies than females (P < 0.001) and used consistently larger annual home ranges than females (P < 0.01), we found little support for the body-size hypothesis. In contrast, we found sex-specific support for the habitat-productivity hypothesis. Male and female mule deer had home ranges of similar size in areas of high habitat productivity but males used larger home ranges than females when habitat productivity was low, Our results suggest that differential sex responses to productivity may be the mechanism underlying the frequent observation that male cervids have larger home ranges than female cervids.

Predicting home range size from the body mass or population densities of feral pigs, Sus scrofa (Artiodactyla: Suidae)

AbstractTelemetry studies of feral pigs (Sus scrofa, L.) in different habitats were used to predict home range size, from (i) body mass and (ii) population density. Geometric mean regressions of the loge transformed data indicated that body mass of male and female feral pigs and mean population density were good predictors of the home range size of feral pigs (r2 = 0.81, 0.77 and 0.85 respectively). There were no sexual differences in home range size of feral pigs once the effect of body mass was taken into account. Use of these variables in models that incorporate spatial aspects along with the practical application of the results to the management of feral pig populations are briefly discussed.

Effects of forest fragmentation on frugivorous and nectarivorous bats in French Guiana

The effects of tropical forest fragmentation on frugivorous and nectarivorous bats were studied on recent islands created by the flooding of a dam in French Guiana. Study sites include forest islands isolated by water, and control plots in nearby continuous forest. Studies began 1y before the onset of forest fragmentation and encompassed the first 3y after flooding. Forest fragmentation greatly modified the diversity and abundance of bats. Changes occurred more rapidly in the smallest fragments than in the largest one, and trends were remarkably similar among all the studied islands. Bat captures in islands were characterised by the scarcity of understorey frugivores. Differences in home range size and foraging strategies may explain why understorey fruit bat species are more sensitive to fragmentation than canopy ones. Changes in the frugivorous bat community may have indirect consequences on both the demographic and the genetic structures of plant populations inside forest fragments.