Male Home Range Size Research Articles

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.

Spatial and social organization of a carnivorous marsupial Dasyurus hallucatus (Marsupialia: Dasyuridae)

AbstractThe northern quoll Dasyurus hallucatus is a sexually dimorphic carnivorous marsupial found in northern Australia. Despite males weighing up to 1120 g, in at least some populations all males die after mating. Radio‐tracking and live‐trapping at a lowland savanna site in Kakadu National Park indicated that females occupied home ranges averaging 35 ha with intra‐sexually exclusive denning areas. There was some overlap of foraging ranges when the density was 3–4 females/km2, but no overlap during periods of lower population density (1–2 females/km2). Male home‐range size may be similar to females before the mating season, but expands during the mating season to > 100 ha to overlap extensively with several female ranges and numerous other male ranges. Despite this range overlap, both sexes were solitary. Even during the mating period, males denned on average 0.27 km from females during the day. During the mating period, each female was visited by at least one to four males per night. During this period, the increase in scat deposition in prominent positions in the landscape and the simultaneous increase in sternal gland activity of the males suggest the importance of olfactory communication to advertise the presence and sexual status of individuals. Males adopted a roving strategy, regularly visiting several widely spaced females in rapid succession, presumably to monitor the onset of oestrus. This intense physical effort during the mating period is likely to be a major contributor to the physiological decline of the males and subsequent die‐off after the mating period. The marked sexual dimorphism of D. hallucatus may be the result of selection for larger, wider‐ranging males in a promiscuous mating system and for energetically efficient smaller females, as females rear the young alone.

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

Increases in population density often are associated with a change 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 density becomes too high, the energetic cost of defending a territory will eventually outweigh the reproductive benefits associated with territoriality. Consequently, males in high density populations may abandon territoriality and adopt dominance polygyny, lekking behavior, or scramble competition. We investigated the relationship between population density and mating system structure in three populations of the chuckwalla, Sauromalus obesus (= ater), near Phoenix, Arizona. Densities in the Phoenix Mountains (2.7 chuckwallas/ha) were lower than any population previously studied. In the Santan Mountains (10.9 chuckwallas/ha), densities were similar to populations studied in the Mojave Desert, and in the South Mountains (65 chuckwallas/ha), densities were the highest yet recorded. Male mating behavior was examined by determining home 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 all three populations, whereas home ranges of males and females consistently overlapped, indicating that males were strictly territorial. This conclusion was supported by behavioral observations of interactions among individuals in a natural setting. The number of females wihin male territories was correlated with food resources (plants) in all three populations. Female home range size appeard to be related to food resources whereas male 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 about the relationship between density and resource defense. Copyright 2002.

The influence of body mass on daily movement patterns and home ranges of the collared lemming (Dicrostonyx groenlandicus)

While the determinants of animals' space use have been addressed in a large number of studies, its intrasexual variability has received only limited attention. By means of radiotelemetry we found body mass to influence home-range size and distance moved by adult collared lemmings (Dicrostonyx groenlandicus) in northeast Greenland. Male body mass was positively correlated with home-range size. Distance moved by both males and females was also correlated with body mass, but with opposite trends: male movement distances increased with body mass, while female movement distances decreased. This may reflect the fact that larger females occupy the most favourable habitats, i.e., the habitats that minimize the need for movement, and thus exposure to predators, without limiting the food supply. The variability in male home range size and distance moved resulted in variability in the number of females accessible to each male. Larger males had access to more females, and hence, body mass was indirectly important for individual mating opportunities. However, increasing access to females was associated with higher costs in terms of mass loss, probably as a consequence of increased energy requirements and exposure to predators.

Sociality in the gray mouse lemur (Microcebus murinus) in northwestern Madagascar.

The mating system and social organization of the gray mouse lemur (Microcebus murinus) was investigated in two three-month field studies (covering a period before, during, and after the first mating season) in Ampijoroa, northwestern Madagascar. The spatial and temporal distribution of the sexes within a population was studied using mark/recapture techniques and radiotelemetry to assess possible contest or scramble competition between the males. Sociality was inferred from the occurrence and probability of nocturnal social encounters, the temporal stability of daily sleeping groups, and nocturnal ranging patterns of co-sleepers. Males and females were evenly distributed in the study area within a network of highly overlapping home ranges. No indications were found for the spatial monopolization of the females by certain dominant males. Males and females had spatial access to several potential mates; the mating system is therefore characterized as a multi-male/multi-female system. Male home range sizes increased during the first mating season, which was interpreted as an indicator for scramble competition between the males. Competitive mate searching, sperm competition, and temporary mate guarding as well as female mate choice are suggested as the most probable reproductive strategies. Over the course of the study the animals lived continually within the study area, and most females formed stable individualized sleeping associations. Females that slept together shared a higher percentage of their home range than did females that slept at different sites. It is suggested that this network of social relationships should be described as a dispersed but individualized neighborhood.

Does Access to Females or Competition among Males Limit Male Home-Range Size in a Promiscuous Rodent?

To maximize fitness, female mammals attempt to maximize offspring survival, whereas males attempt to mate with as many females as possible, which results in differential use of space. The relative influence of male competition versus access to females on space use by males has not been addressed theoretically or empirically. We conducted an experiment in which we manipulated total density, density of females, and density of males to determine relative influence of density of each sex on space use and overlap by male gray-tailed voles (Microtus canicaudus). Home-range size was correlated inversely with total density and was influenced separately by each sex. Home-range sizes of males were significantly smaller in high male-low female populations than in low female-high male populations. Males overlapped 4–5 females and 4–5 other males in populations with low densities of both sexes and high densities of both sexes. When sex ratios were skewed toward females, males still overlapped 4–5 females but only one other male. When sex ratios were skewed toward males, males overlapped only two females while overlapping three other males. Home-range size of a male does not appear to expand beyond an overlap with about five members of either sex. Thus, intrasexual competition with five males or overlap with five females appear to set upper limits to home-range size of male gray-tailed voles. We conclude that space use by males is influenced by intrasexual competition and access to females with an upper limit of overlap with either sex.

Female distribution affects mate searching and sexual selection in male northern water snakes ( Nerodia sipedon )

Mating systems and sexual selection are assumed to be affected by the distribution of critical resources. We use observations of 312 mating aggregations to compare mate-searching success of male northern water snakes (Nerodia sipedon) in two marshes in which differences in mating substrate availability resulted in more than fourfold differences in female dispersion. Reproductive males had significantly larger home ranges where females were dispersed than where females were clumped. The number of females encountered by males increased significantly with male home range size where females were dispersed, and decreased significantly where females were clumped. Where females were clumped, males were more likely to encounter other males when they located females. We found no evidence in either population that mate searching was energetically expensive or that males with relatively more energy had larger home ranges. However, males with greater fat reserves at the start of the season participated in more mating aggregations when females were dispersed, suggesting that fat reserves could affect a male’s willingness to attempt mating or to persist in aggregations. When females were dispersed there was weak stabilizing selection acting to maintain male body size (β=–0.14), but strong directional selection favoring larger (β=0.50) and fatter (β=0.37) males. Over 7 years, the intensity of selection favoring larger males varied substantially (β=0.14–1.15), but that variation was not related to variation in the operational sex ratio. We found no evidence of directional selection on either body size (β=0.05) or fat reserves (β=0.10) of males when females were spatially clumped. Overall, the distribution of females had a pronounced effect on male behavior, on the factors that affected male success in locating females, and probably on the extent of sperm competition once females had been located.

Home range of the Tropidurid lizard Liolaemus lutzae: sexual and body size differences

The home range of the Tropidurid lizard Liolaemus lutzae, an endemic species of the costal sand dune habitats of Rio de Janeiro State, was studied in the beach habitat of Barra de Maricá restinga, Maricá County. Home ranges were studied using a mark-recapture technique in a delimited area at the beach habitat. I considered for estimates and analysis the home ranges of those lizards with a minimum of four positions. The size of L. lutzae home ranges varied according to the segment of the population. The mean home range size of adult males (x = 59.8 ± 33.7 m²) was significantly larger than that of adult females (x = 22.3 ± 16.1 m²). Juvenile mean home range size was significantly smaller than that of adult males, but did not differ from that of adult females (t = 1.058; p = 0.149). The overlap between male home ranges was usually low (3.6%), being in general only peripheral. Conversely, there was a considerable overlap between home ranges of adult females with those of adult males, the home range areas of two or three females being enclosed in the home range of one adult male. The small overlap between home ranges of adult males suggested mutual exclusion. The observed between-sex differences in the size of L. lutzae home range may be explained by the sexual dimorphism in body size in this species, and by the need of adult males to establish larger areas so as to include many females in their areas, during the reproductive season. The differences in home range along ontogeny probably result from differences in body size of the different segments of the population, due to trophic differences (carnivory and herbivory levels), and the dispersal of young after birth. Because L. lutzae is omnivorous, but primarily herbivorous when adult, and due to its sit-and-wait foraging behavior (mainly on arthropods), it does not need to move around over large areas to find food, which in turn reduces the area necessary for it to live.

Spatial and Breeding Relationships of the Lizard, Anolis Carolinensis: Evidence of Intrasexual Selection

1. We used continuous 8-day monitoring to document the spatial and mating relationships of free-ranging Anolis carolinensis lizards at each of seven habitat-delineated study sites. 2. We found a polygynous social structure, consisting of a male and 2-6 resident females (x = 3.3), on each site. 3. Spatially, both sexes utilized all available perch heights and diameters on the study sites (habitat generalists), though females tended to perch slightly higher and on significantly thinner substrata (x = 2.4 m, 3.4 em, respectively) than males (x = 2.3 m, 5.3 em, respectively). 4. Mean home range volume was eight fold greater for males (69 m3) than females (8 m3). Male home ranges were exclusive of other males (0% overlap), while neighboring female home range volumes overlapped an average of 18%. 5. Male snout-vent length (SVL) was positively correlated with male home range size (area, volume) and with number of resident females, but not with resident female SVL or resident female home range size. 6. Half of 397 male-female encounters led to close contacts in which males influenced courtship outcomes by: recognizing receptive and non-receptive females (differential display rate); bypassing 69% (85/123) of mating opportunities with receptive females; and copulating only when courtship was male-initiated. 7. Larger males (who also had larger territories and more females) courted less per female, but with longer duration, and had longer copulatory durations than smaller males. 8. Male frequency of copulation (x = once/1.4 days), however, had no correlates with measured variables; females were mated without bias to male or female attributes. 9. Male potential reproductive rate (PRR), estimated from the number of copulations with different females, positively correlated with male SVL. Female PRR, estimated from the inter-mating interval (i.e. the single-egg clutch interval), did not correlate with any measured male or female trait. 10. Our data, in concert with other field studies and A. carolinensis life history traits, document a polygynous mating system in which females seem to fit a 'no cost, neutral-mate-choice' model, and males (in response to sedentary, contiguously distributed females who clutch at weekly intervals over a 4-month period) employ territorial contests within an endurance rivalry as a prime mechanism for mate assortment.

Spatial organization and social relations in the Eurasian lynx population in Bialowieza Primeval Forest, Poland

The home range size, spacing pattern and intraspecific relations in the lynx Lynx lynx (Linnaeus, 1758) were studied in Bialowieza Primeval Forest (eastern Poland), in 1991-1996. Eighteen lynx (11 males and 7 females) were captured and radio-collared. The mean autumn-winter home range size was 165 km2 for males and 94 km2 for females. In spring-summer, it was 143 and 55 km2, respectively. The mean life-time home ranges were 248 km2 for males and 133 km2 for females. Male home range size did not change significantly between autumn-winter and spring-summer seasons, however, their ranges icreased by 40-90% just before and during the mating season (December-March). The home range of females in the autumn-winter season was almost twice as large compared with the spring-summer period (94 vs 55 km2). The smallest home ranges were observed in breeding females during the two months after parturition (10 km) and these grew until the following spring. The home ranges calculated for 5-month periods shifted on average 4 km in adult males, 2.7 in adult females and 4.7 km in subadult males. One of the farthest shifts in the adult male range (8.7 km) was explained by the death of a neighbouring resident. The average overlap between adult males' ranges was 30%, while those between females was 6%. The largest overlap occured between adult males and females (62%) as well as between adult and subadult males (75%). The lynx showed a tendency to avoid each other. The average distance between neighbouring adult males was 11.6 km, and they were never found closer than 1 km to each other. The average distance between neighbouring females was 8.1 km. Besides a few meetings between males and females (during and outside the mating season), they were located separately (4.4 km from each other, on average). In 93% of the cases an adult female was recorded with her dependent kittens. It was concluded that home range size and spacing pattern in male lynx depend on the distribution of females, whereas spacing in females was determined by food-related factors.

Population and movement characteristics of radio-collared striped skunks in North Dakota during an epizootic of rabies.

We observed a total of 102 striped skunks (Mephitis mephitis) from March to July of both 1991 and 1992 in Stutsman County, North Dakota (USA) during an experiment with food supplementation. Twenty-three apparently healthy skunks in 1991 and 56 in 1992 were equipped with radio-collars. In 1991, one of the 23 was tested and found to be rabid. In 1992, 50 of 56 were tested; 35 (70%) were rabid. Of skunks with ages estimated, 19 (66%) of 29 were first year animals in 1991 compared with nine (22%) of 41 first year animals in 1992. All 18 females captured in 1991 were pregnant or parous compared with 21 (60%) of 35 in 1992. The estimated survival rate of skunks was 0.85 during April to June 1991, but only 0.17 during April to July 1992. In 1992, the survival rate of first year skunks was 0.08, compared with 0.35 for older animals. Eleven (31%) of 36 skunks found dead of rabies or in late clinical stage were located below ground. We detected no differences in 1992 between healthy and rabid skunks in estimated mean (+/- SE) rate of travel (232 +/- 14 m/hr), distance traveled (2,047 +/- 141 m/night), or home range size (1.6 +/- 0.4 km2) during half-month periods from April through June. Among rabid skunks, mean rate of travel tended to decrease from 298 +/- 48 m/hr during the 14 days preceding the clinical period of rabies (pre-clinical) to 174 +/- 48 m/hr during the clinical period of rabies (14 days immediately before death). Similar decrease occurred in distance traveled in a night (2,318 +/- 281 m, pre-clinical; 1,497 +/- 281 m, clinical). Mean home range size of males (2.8 +/- 0.4) was greater than of females (1.2 +/- 0.4) during the pre-clinical period, but during the clinical period home range sizes of males (1.8 +/- 0.4) and females (1.8 +/- 0.4) were similar. Mean home range size of females did not differ between pre-clinical (1.2 +/- 0.4) and clinical (1.8 +/- 0.4) periods (P = 0.22). Deaths of skunks from rabies in 1992 tended to be more spatially clumped than expected had they been random, mostly due to deaths detected before 8 May. We detected no correlation between locations of animals found dead of rabies and dates of death.

Mule Deer Movements in Response to Military Activity in Southeast Colorado

During January 1986-September 1988 we studied the behavioral responses of 71 radiocollared mule deer (Odocoileus hemionus) to military activity on the Pinon Canyon Maneuver Site in southeastern Colorado. Military training was initiated on the site during August 1985 and recurred about 3 times yearly for periods of one month. During a maneuver, 3/7 of the site was used for training in accordance with a rotational land use schedule. During the nonsummer seasons, female seasonal convex polygon and harmonic mean home ranges were larger in maneuver and previous-maneuver areas than nonmaneuver areas (P < 0.002). During summer, female convex polygon home ranges were larger in maneuver than nonmaneuver areas (P = 0.066). Fawn summer home ranges were larger in maneuver than previous-maneuver areas (P < 0.01). Male home range sizes differed only for 50% harmonic mean transformation annual home ranges (P = 0.056); bucks in maneuver areas had larger home ranges than in nonmaneuver areas. Female deer in maneuver areas exhibited significant home area shifts (P = 0.049) between premaneuver and maneuver periods more frequently (40.0%) than did deer in nonmaneuver (control) areas (12.5%). Mule deer in military training areas may have responded to human harassment, alteration of security cover, or destruction of the forage base. We suggest that deer may respond more intensely to unpredictable than predictable human activity.

Wintering site fidelity and movement patterns of Western Sandpipers Calidris mauri in the San Francisco Bay estuary

Western Sandpipers Calidris mauri are the most numerous shorebird species in the San Francisco Bay estuary during winter. A sample of 106 Western Sandpipers was captured in mist nets and radio‐marked with 1‐g transmitters to examine their wintering site fidelity and movements. Differences in distances moved, home range extent and core area size were examined by age, sex, season, site, time of day and tide. All birds remained in the south San Francisco Bay region during winter and exhibited strong site fidelity, with a mean home range of 22.0 km2 or only 8% of the study area. First‐year birds had larger home ranges (26.6 ± 3.6 km2) than adults (17.2 ± 2.5 km2) in winter, but home range sizes of males and females were not significantly different in any period. Home range sizes were similar between seasons, but core areas were smaller in spring (6.3 ± 1.2 km2) than in early (9.6 ± 4.0 km2) or late (11.6 ± 1.6 km2) winter. Movements and home range size were similar for radio‐marked birds located during day and night. The high degree of regional and local site fidelity demonstrated that the mixture of natural mud fiats and artificial salt ponds in southern San Francisco Bay provided sufficient resources for large wintering populations of Western Sandpipers.

Activity, movement, and home range of Virginia opossums (Didelphis virginiana) in Florida

The activity and spatial organization of the Virginia opossum (Didelphis virginiana), a solitary didelphid marsupial, were studied in north-central Florida. Opossums were strictly nocturnal, and the activity level peaked between 2000 h and 0200 h. Activity was influenced by temperature. Below 8°C, duration of nightly activity decreased strongly with decreasing temperature. Above 8°C, activity tended to decrease with increasing temperature. Average nightly activity did not differ among months from August to December or between males and females. Opossums lived in well defined and at least seasonally stable home ranges with moderate to extensive home range overlap. Females tended to more exclusive space use and greater stability of home ranges than mates. Males often shifted home ranges at the end of mating seasons. Three different measures of home range size were presented. Average values for males and females were 141.6 ha and 64.4 ha, respectively (corrected minimum convex polygon). Individual home range sizes of males were influenced by habitat being larger in presumably poorer habitats, and by body size. Average distances moved per hour were 234 m in males and 178 m in females. Nightly movements of males and females averaged 1835 m and 1465 m, respectively (maximums 4665 m and 3973 m). Distances traveled were associated with temperature, home range size or body size. Very limited data from other regions suggest greater space use by opossums in the studied population.

Reproductive energetics of adult male yellow-bellied marmots (Marmota flaviventris)

We examined the energy expenditure of adult male yellow-bellied marmots (Marmota flaviventris) and its relationship to various female-defense characteristics critical to male reproductive success. Resting metabolic rates of males were estimated in the laboratory via oxygen-consumption analysis, and field metabolic rates were estimated using a doubly labeled water technique. Male home-range size, number of females defended by males, dispersion of females in the habitat, and date into the active season were considered to be predictors of male energy expenditure in excess of maintenance costs (field metabolic rate minus resting metabolic rate). Energy expenditure was best explained by a defensibility index based on the number and dispersion of females defended; expenditure increased with number and dispersion of females. Energy expenditure increased with date into the active season. Environmental constraints on male activity during the mating season may have led to a shift in male reproductive investment to later in the season, when intruder pressure by conspecifics increased. No short-term survival costs were associated with high energy expenditure; males appeared to engage in reproductive behaviors congruent with their physiological capabilities.

Size and overlap of home range in a high density population of the Japanese Field vole Microtus montebelli

Relationships of size and overlap of home range with the population density in a flood plain population of Microtus montebelli (Milne-Edwards, 1872) with high density were examined from April to December 1993 using mark-recapture method. Population density in the study area was reached 280 males/ha nad 236 females/ha in summer. Although reproductively active voles were present throughout this study, more than half of females underwent reproductively resting period in summer. Main breeding seasons were spring and autumn when the density was relatively low. While the home range size of adult males did not decrease in summer when the population density was higher than in spring or autumn. In summer, males showed significantly larger degree of home range overlap than in spring or autumn, while home ranges of females overlapped little throughout this study. These results differed from those of the previous studies on this species, possibly due to much higher density in mountainous populations.

Intrasexual Competition and Spacing Behaviour in Male Field voles, Microtus agrestis, under Constant Female Density and Spatial Distribution

The influence of male density on the spacing behaviour of male field voles, Microtus agrestis, was experimentally investigated in field enclosures. Males were radio-tracked at different densities (3 or 6 males per enclosure) with the same density of females (five in each enclosure) placed in stationary cages. Male density influenced individual males' spacing behaviour. Home ranges were smaller and overlapped more, and movement activity was lower at the high male density. Furthermore, at high male density home range size varied more between individuals; small home ranges were smaller at high male density than at low density, whereas the largest home ranges were of similar size in the two experimental setups. These results suggest that at high male density competition between males increases and, consequently, less competitive males suffer from the increased competition. Finally, intrasexual competition apparently constitutes an important influence on the spacing system of male field voles

Dynamics of space use and male vigour amongst wood mice, Apodemus sylvaticus, in the cereal ecosystem

The spatial organisation of male and female wood mice, Apodemus sylvaticus, was investigated in a large-scale radio-tracking study on arable farmland near Oxford, United Kingdom, during the breeding season. Both sexes had significantly larger home ranges in the breeding season than at other times, and the breeding season home ranges of male (X = 1.44 ha) were significantly larger than those of females (X = 0.49 ha). Home range overlap was significantly greater between males, and between males and females, than it was between females. Overlap between males tended to be greatest in heavily utilised areas. Except during sexual consortship, there was minimal evidence of dynamic interaction among individuals. Home range sizes of breeding males varied widely, as did their body weights. There was no relationship between male body weight and home range size or any other movement parameter. However, males with the largest home ranges had the highest scores on all other movement parameters, indicating that they expended more energy in movement. These more ‘vigorous’ males had access to the home ranges of more females than did males with small home ranges.

Home Range and Habitat Use of Brown Bears in the Southwestern Oshima Peninsula, Hokkaido

Movement, home range, and habitat use of 10 (7 M and 3 F) brown bears (Ursus arctos yesoensis) were investigated by radiotracking in southwestern Oshima Peninsula, Hokkaido, from May 1987 through May 1990. The annual home-range size was 28.1-39.1 km2 for 1 female. Male home-range size was larger than that of females, although no males were monitored throughout the year. Lower deciduous natural forest areas such as beech-oak (Fagus crenata)-(Quercus monoglica var. grosseserrata) forest and maple-linden (Acer mono)-(Tilia japonica) forest were used by bears intensively, but subalpine areas such as sasa-birch (Sasa kurilensis or S. senanensis)-(Betula ermani) forest and sasa community were rarely used and usage was restricted. Food availablilty could influence the habitat selection by the bears. Int. Conf. Bear Res. and Manage. 9(1):319:325 Hokkaido brown bears have been killed indiscriminately for more than 120 years. Especially during the period of 1966 through 1989, the spring prophylactic killing system was in force, and many bears were killed as pests and as game animals. Forest and field areas have been developed without considerations of bear habitat maintenance. As a result of these pressures, conspicuous extinction or near extinction had occurred by the 1980s in northern Hokkaido (Aoi 1990) and in areas such as the Shakotan Peninsula and the Yoichidake-Eniwa mountain area (Hokkaido Government 1986). However, recent bear damage to livestock and crops still occurs in other parts of Hokkaido (Hokkaido Government 1986). It is obvious that with the control kill alone, damages will continue to occur until the bear population drops to near extinction. Since mid 1970, about one-fourth of the total brown bear damage in Hokkaido has occurred (annually) in the Oshima Peninsula (Hokkaido Government 1986), which occupies only about 9% of the island. As this area is a peninsula, characterized by having a very long boundary between bear range and human residential areas, troubles and conflicts between people and bears are apt to occur. Moreover, habitat development on the Oshima Peninsula could have a major influence on bear habitat and population maintenance on Hokkaido. Biological information such as brown bear home range and habitat use is required for proper habitat management. The first successful brown bear radio-telemetry study in Hokkaido, Japan, was initiated in southwestern Oshima Peninsula in 1987. In this paper, I present preliminary information on movement, home range, and habitat use of Hokkaido brown bears in the deciduous forest of this area. I thank K. Maita and S. Kojima for their devoted field assistance. I thank also M. Yoneda, H. Abe, T. Aoi, H. Kudo, and T. Akasaka for their helpful advice and suggestions. Y. Maruko, A. Kishikawa, J. Yamazaki, T. Tsuizuki, G. Suzuki, N. Sato, T. Sato, and K. Takahashi, who are the members of the Hokkaido Hunting Society, kindly cooperated with the study. T. Tsubota, K. Yamamoto, Y. Kamada, and the members of the Brown Bear Research Group of Hokkaido University also provided devoted field assistance. Y. Sawamura and K. Kudo provided assistance in aerial radio location. The Matsumae District Forestry Office of Hokkaido also gave facilities for investigations. K. Kanagawa cooperated with the English. This research was partly funded by the Japan Environmental Agency. Asahi Broadcasting Co., Iwanami Productions Inc, and Tokyo Broadcasting System Inc. also provided financial assistance.

Red-Shouldered Hawk Home-Range and Habitat Use in Southern California

Space and habitat use patterns of adult red-shouldered hawks (Buteo lineatus elegans) in southern California are relevant to land-use planning and the conservation of this species. Thus, we determined average home-range size through radio telemetry to aid such planning. Average home-range size was 1.21 km'for 7 males and 1.01 km'for 6 females. A non-territorial male floater used a home range 30 times larger than the mean of 7 other males. Core areas averaged 7.5% and 4% of home-range size for males and females, respectively. Red-shouldered hawks used 4 woodland habitats more than expected due to chance, and 4 nonwoodland habitats less than expected; the overall pattern of habitat use was the same for both sexes. Home ranges in mesic riparian habitats were smaller than those in more xeric oak (Quercus spp.) woodlands