Home range size, overlap, and habitat selection of diurnally roosting Eastern Whip-poor-wills ( Antrostomus vociferus ) during the breeding season

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

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

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

We studied seasonal variation in size and fidelity of home range in a population of eastern side-blotched lizards, Uta stejnegeri, in southern Coahuila, Mexico. Field work was carried out during the active seasons of 2002–2004. Home ranges during breeding and non-breeding seasons were larger for males than females and were reduced in both sexes during non-breeding months (autumn). There was greater intersexual overlap of home range during summer and less in autumn. Intrasexually, males had more overlap in home range than females (particularly during summer), which could be related to their large home ranges during that season. Fidelity to home range from one season to the next in a given year was similar in males and females. Although males had greater length and mass than females, neither measure correlated with size of home range. Density of adult lizards was negatively correlated with size of home range during the reproductive period. During non-reproductive months, density of all age classes combined was negatively correlated with size of home range. Our results indicate that home range sizes of U. stejnegeri vary considerably over the year and diverse factors are involved.

Home Range Use by Abert Squirrels: A Comparative Analysis

Spatial ecology and habitat use of giraffe (Giraffa camelopardalis) in South Africa

Social organization influences carnivore demography, space use, density, and abundance. In bobcats (Lynx rufus) social organization is thought to be affected by multiple interacting factors including relatedness, sex, and prey and conspecific density. To provide baseline data on the effect of relatedness on bobcat social organization, I examined space use and overlap among two sibling, adult female bobcats in east-central Minnesota, and compared these results to previously published research. Estimated bobcat home range size was similar to that of previous studies, suggesting stability in home range size across several decades and reliability in our estimates. Home range and core area overlap was within the range of previous studies. However, the use of two different methods for estimating core area suggested that the subjective use of the 50% utilization distribution would have underestimated core area size and overlap. Although limited, these data provide the first estimates of home range and core area overlap among adult sibling bobcats.

The home range is the space used by individuals to carry out their life cycles. The Sand dune lizard (Liolaemus multimaculatus) is a vulnerable species, endemic to the pampas coasts of Buenos Aires and Río Negro Provinces in Argentina. The aim of this work was to assess home range size and overlap of the Sand dune lizard. The study was carried out at Mar Chiquita Provincial Reserve. Home range and overlap were calculated using the minimum convex polygon method. The mean ±SD home range size for all individuals was 45.90 ± 74.37 m2 and no differences were observed between males and females (p = 0.49). However, an analysis without outlier individuals showed more accurate values for females (21.31 ± 17.59 m2) and males (33.52 ± 24.62 m2), and differences between sex were observed (p = 0.04). The relationship between body size and home range size was not significant (p = 0.41). Home range overlap was high (22 to 58%; Fig. 2) and did not show differences between males and females (p > 0.05 in all cases). Our results showed some similarities with the Brazilian sand lizard (Liolaemus lutzae) in which home range value is only up to 1.5 units higher than in L. multimaculatus. Further studies about this species' social system are necessary to understand the observed patterns.

Mountain gorillas are highly folivorous. Food is abundant and perennially available in much of their habitat. Still, limited research has shown that single gorilla groups heavily used areas where food biomass and quality were relatively high and where they met daily nutritional needs with relatively low foraging effort. Also, ecological factors influenced solitary males less than groups with females. Long-term data on habitat use by multiple mountain gorilla social units and more extensive data on variation in food distribution, presented here, confirm that food distribution influences areal occupation densities across groups and over time. These data also confirm the group/solitary male distinction and show that food distribution became more important for one male once he acquired females. Groups used ≤25 km2, and inter-annual home range and core area overlap was often low. Annual home range and core area size varied considerably within groups and across years. It bore no simple relationship to group size and estimated group biomass. Core areas were biased samples of total home ranges and were relatively good foraging areas. One group abruptly shifted its home range in response to male mating competition. Home ranges of two others expanded from 1981 to 1987, though at a decreasing rate. Data on one such group, which varied considerably in size, are consistent with arguments that costs of scramble competition are low except in unusually large groups. Low site fidelity, low scramble costs, and high home range overlap should decrease the ecological costs of female transfer.

Ecological attributes of a species can vary as resource requirements and social interactions change in response to the annual reproductive cycle. We examined variation in home range size, home range overlap, activity (2005–2006), and food item selection (2006–2007) of island foxes (Urocyon littoralis) on San Nicolas Island relative to reproduction-related events. Home ranges, particularly for males, were larger during the mating period compared with the post-mating, pup-rearing, and non-reproduction periods. Home range overlap with non-mate neighbors also increased during the mating period. The greater home range size and overlap during the mating season is consistent with foxes, particularly males, traveling into the ranges of neighboring pairs in an attempt to secure extra-pair copulations. Daily activity patterns did not vary among the reproductive periods. Use of vertebrate prey items increased during the period when adults would have been provisioning weaning young. These items (e.g., mice, birds, lizards) are protein-rich and easier to transport compared with smaller items (e.g., fruits, snails, insects) that also are commonly consumed by island foxes. Variation in ecological attributes among island foxes across the different seasons defined by reproductive events likely represents efforts to maximize mating opportunities, particularly among adult males, and to secure optimal resources for provisioning growing young. These patterns are consistent with those observed among other small canid species.

Very little is known about the home range and movement patterns of tinamous. The Ornate Tinamou (Nothoprocta ornata), a species of the central Andes that is important for cynegetic and biomonitoring purposes, was previously reported to have a very small territory (2.43 ha). This was based solely on field observations. In order to gain a better understanding of the movement patterns, home range size, and home range overlap of this species, we radio tracked 12 adult individuals in an Andean agro-ecosystem for a full year. The birds remained within their home ranges all year; 100% MCP (minimum convex polygon) home ranges were 43.8 ± 21.6 ha (22–85 ha), 95% kernel home ranges were 58.8 ± 31.9 ha (25–118 ha) and 50% kernel core areas were 15.3 ± 8.9 ha (6–33 ha). Only two birds, probably sub-adults, showed extensive movement patterns before their death. Individuals overlapped their home ranges extensively (from 30–98% with 2–3 tagged individuals), but these values were probably higher because a small proportion of the population was tagged. No sexual differences were detected in home range size or overlap. Our results support the usefulness of Ornate Tinamou as a sentinel species in biomonitoring studies and highlight the need for further research into the philopatric and dispersion behavior of juveniles before planning cynegetic strategies.

Understanding factors driving resource selection and habitat use of different species is an important component of management and conservation. Feral horses (Equus caballus) are free ranging across various vegetation types in the western United States, yet few studies have quantified their resource selection and seasonal use. We conducted a study to determine effects of vegetation community, distance to water, and topographic variables on seasonal resource selection in 2 feral horse populations in Great Basin sagebrush (Artemisia spp.) ecosystems of west‐central Utah, USA: Conger Herd Management Area (HMA) and Frisco HMA. We deployed global positioning system (GPS) radio‐collars on 38 female horses and GPS‐transmitters braided and glued into the tail hair of 14 males, collecting locations every 2 hours for 1–4 years between 2016 and 2020. We calculated home range size and core use area of social groups (harems) and bachelor males using auto‐correlated kernel density estimators for each biologically defined season (breeding, fall, and winter) per study year. We examined seasonal home range size and overlap of harem groups and bachelor males and compared movement speed of bachelors and harems among seasons. We determined seasonal resource selection in a use‐availability framework using resource selection functions. We hypothesized that horses would select for areas of high herbaceous vegetation, that water would be a key variable in resource selection models like other equids, and home range size in winter would be largest because horses can eat snow for hydration and could therefore roam farther from surface water. Mean annual home range size was 103.12 ± 37.38 km2 (SD) for Conger harems and 117.47 ± 32.75 km2 for Frisco harems. At Conger there was no difference in home range size between harem groups and bachelor males, but home range size was smaller in winter than other seasons, whereas winter home range size at Frisco was larger than other seasons. Bachelor males moved at higher speeds than harems during all seasons, and harem groups from both populations had lower movement speeds in winter. Harem groups had distinct winter ranges with little overlap on breeding season ranges. In both populations, all horses selected for herbaceous vegetation types and avoided forest relative to shrubland throughout the year. Harems at Frisco were consistently located closer to water sources, whereas selection for water sources by Conger harems varied seasonally, with winter having the lowest selection. Harem groups at Conger had an average of 10.6% of their home ranges outside the HMA boundary and Frisco harems had up to 66.8% outside, likely because of the horseshoe shape of Frisco HMA in which shrub meadows (foraging areas) comprise the horseshoe center, which is outside the HMA. Our results highlight the importance of water sources, which were a key predictor of horse movement patterns in our study. We emphasize the utility of telemetry devices to understand resource selection of feral horses at a fine scale, enabling management to be more targeted and facilitate planning.

A variety of methods are commonly used to quantify animal home ranges using location data acquired with telemetry. High-volume location data from global positioning system (GPS) technology provide researchers the opportunity to identify various intensities of use within home ranges, typically quantified through utilization distributions (UDs). However, the wide range of variability evident within UDs constructed with modern home range estimators is often overlooked or ignored during home range comparisons, and challenges may arise when summarizing distributional shifts among multiple UDs. We describe an approach to gain additional insight into home range changes by comparing UDs across isopleths and summarizing comparisons into meaningful results. To demonstrate the efficacy of this approach, we used GPS location data from 16 bighorn sheep (Ovis canadensis) to identify distributional changes before and after habitat alterations, and we discuss advantages in its application when comparing home range size, overlap, and joint-space use. We found a consistent increase in bighorn sheep home range size when measured across home range levels, but that home range overlap and similarity values decreased when examined at increasing core levels. Our results highlight the benefit of conducting multiscale assessments when comparing distributions, and we encourage researchers to expand comparative home range analyses to gain a more comprehensive evaluation of distributional changes and to evaluate comparisons across home range levels.

Home range size, overlap and exploitation in domestic farm cats is examined. Data were collected on the 11 adult cats (5 O'O'; 6 ♀♀) living on 3 Swiss farms throughout 1984; 8 of the cats were fitted with radio transmitters. Census-point and focal animal methods of data collection were employed. From area-observation curves we concluded that our home range maps (and sizes) were good approximations of the areas utilized by the animals in 1984. Correlations existed between range size and 1) the number of map-fields visited per day by the cat (+); 2) the percentage of observations at the primary home (-); 3) the proportion of the range visited each day (-); and 4) the percentage of map-fields used only by one cat (+, but only for males). The general pattern of social organization found elsewhere was confirmed: males were generally more tolerant of each other than females (based on range overlap), especially considering animals living on different farms. Animals from the same primary home showed considerable range overlap. Male ranges were much smaller than expected (not even twice as large as the female ranges, whereas they should have been about 10 times the size, based on all other studies). These results are discussed in connection with male reproductive strategies, cat density and patterns of range utilization. And lastly, we could demonstrate coordination of hunting activity in time and space by two adult individuals on one farm (sibs), adding to the list of behavior patterns illustrating facultative sociality of house cats.

Patterns of space use and sexual dimorphism are frequently used to infer mating systems. We examined body size and home range size and intra- and intersexual overlap degree in order to elucidate mating strategy of Akodon azarae males. We studied spacing patterns using 113 and 129 home ranges established by males and females, respectively, in four 0.25 ha enclosures during the breeding season. Significant differences between sexes in home range size and overlap degree were found. Male home ranges were always larger than those of females. We observed exclusive space use among males and among females. Considering only those males that shared their home ranges with females, average intersexual overlap value was about 50%. Males mainly overlap their home ranges with home ranges of two or three females. Significant differences in body size were found between males and females, with males being larger. We concluded that space use and sexual dimorphism in this species is consistent with patterns characteristic of polygynous rodents, and we propose a polygynous system in A. azarae.