Home Range Size Research Articles

Space use of polar bears (<i>Ursus maritimus</i>) in Davis Strait in relation to sea ice and harp seals (<i>Pagophilus groenlandicus</i>)

Polar bears (<i>Ursus maritimus</i>) rely on seals as their primary prey, yet predator-prey spatial relationships are poorly understood. We examined the spatial relationship between Davis Strait polar bears and harp seals (<i>Pagophilus groenlandicus</i>), using satellite-telemetry for both species. We analyzed sea ice trends using remote sensing (1979-2021) to examine how their environment may be changing using four sea ice seasons (freeze-up, winter, break-up, and summer). Sea ice cover decreased and summer season lengthened over time. Polar bears (n=23) tracked in 1991-2001 for 7-12 months had a mean 95% minimum convex polygon home range size (MCP) of 102,864 km<sup>2</sup> (SE=15,236 km<sup>2</sup>) and a mean 95% kernel density home range size (KDE) of 66,215 km<sup>2</sup> (SE=59,688 km<sup>2</sup>). Harp seals (n=29) tracked for 5-8 months in 1993-2005 had a mean 95% MCP of 464,330 km<sup>2</sup> (SE=47,009 km<sup>2</sup>) and a mean 95% KDE of 256,016 km<sup>2</sup> (SE=31,566 km<sup>2</sup>). During freeze-up, the core-use areas of both species did not overlap, but the broad-use areas did. During break-up, the broad-use areas overlapped more than the core-use areas. The space use of both species was influenced by the sea ice seasons and these seasons have changed over time.

Is sexual size dimorphism in walleye, Sander vitreus, a driver of seasonal movements in Lake Erie?

Walleye (Sander vitreus) are a sexually dimorphic species in which females are larger than males in adulthood. Walleye can also exhibit sex- and population-based differences in migration behavior. In Lake Erie, we used acoustic telemetry to test the prediction that female walleye exhibit larger broad-scale movements than males during the summer and autumn. This prediction was based on the hypothesis that greater foraging in females would be needed to satisfy their higher energy requirements. We quantified movements of males and females from distinct spawning populations from Lake Erie's west and east basins using a lake-wide grid of acoustic receivers in 2017 and 2018. We found no differences between male and female home range sizes, core range sizes, or distances travelled in either population. Fish length-at-tagging was unrelated to the size of a fish's home range or to its distance travelled, contrary to previous predictions about body size as a driver of migration distance in the Lake Erie population. We found that west basin walleye occupied large and indiscrete portions of the lake, but the core range of females extended into the central basin, whereas males were concentrated in the west basin. Walleye originating from the east basin confined their movements primarily to the east basin and showed stronger home range overlap among members of their population than did walleye from the west basin population. Within either population, walleye had more home range overlap with members of the same sex, which likely reflects differences in the migratory tendencies of males and females.

Ámbito de hogar, preferencia de hábitat y patrones de actividad del zorro de Sechura Lycalopex sechurae (Mammalia: Canidae) en el Desierto de Sechura, noroeste del Perú

The Sechura fox (Lycalopex sechurae) is a little-studied species despite being common in northwestern Peru and listed as Near Threatened internationally. This study presents the home range, habitat preference, and activity patterns of L. sechurae in two locations of the Sechura Desert: The Mangroves of San Pedro de Vice (MSPV) and the Illescas National Reserve (RNI). Using GPS collars, the minimum convex polygon method, and the Kernel estimator (KE), the home range of four female individuals (two from each site) was calculated. Additionally, the GPS location data were used to estimate activity patterns and habitat preferences for each individual. The home range of females from MSPV was 0.6 and 1 km² (95% KE), whereas, for the RNI, it was 3.5 and 25.1 km² (95% KE). Females from MSPV preferred dry forest (54.8% and 76.1%), while those from RNI favored desert scrub (64.3% and 64.5%). All individuals exhibited cathemeral behavior, with increased nocturnal activity. Our results demonstrate variability in home range sizes, similarity in activity patterns compared to other studies, and highlight the importance of dry forest and desert scrub as resource-rich habitats for Lycalopex sechurae.

Home range sizes and nychthemeral habitat uses by the Northern Shoveler (Spatula clypeata) on prenuptial stopovers in Vendée marshes, western France

The wetlands of Marais breton (MB) and Marais poitevin (MP) on the French Atlantic coast are commonly used by several duck species, especially as stopover sites during the prenuptial migration. Understanding the ecological requirements of Anatidae at spring stopover sites is important to define appropriate management actions that might have a carry over effect on the subsequent reproduction success. This study focused on the Northern Shoveler (Spatula clypeata), a species that regularly visits the two marshes during spring and fall migrations and is highly dependent on freshwater invertebrates as the food resource. Fifteen Northern Shovelers were equipped with GPS/GSM tags and monitored during their stopover in both marshes in 2020 and 2021. The aims of the study were to understand the habitat use on stopover sites and relate home range (HR) size with characteristics of the feeding habitats (such as freshwater invertebrates’ density and diversity). The HR area of the studied individuals was mainly constituted of ponds in MB (83% of the HR) and wet meadows in MP (71% of the HR). The Northern Shovelers equipped with tag spent more than 72 consecutive hours in 31 wetlands, using them during the day, at night or all day. The diurnal visited sites were deep ponds that were sparsely vegetated and dominated by microcrustaceans, whereas the nocturnal visited sites were wet meadows or ponds with high aquatic vegetation cover and high invertebrate taxonomic diversity. The 31 described sites appeared to be rich in freshwater invertebrates, with no significant difference in invertebrate densities between the diurnal and nocturnal sites. HR sizes were highly homogenous between the two study sites (MB and MP), between sexes or between age classes. In conclusion, according to this study, an appropriate HR for the Northern Shoveler at spring stopover is 8.49 ± 5.95 km² (mean ± standard error).

Post-release dispersal and home range of translocated red deer in the Vojvodina province (Serbia)

Monitoring of 38 (12 male and 26 female) red deer translocated from Ivo Wildlife Park (Romania) to hunting ground "Bosutske Forest" (Vojvodina, Serbia) was conducted from 2017 to 2021. The red deer were translocated in lieu of the managing authority's efforts to counteract the effects of red deer losses due to catastrophic flooding in the region. All animals were ear-tagged, while 7 males and 10 females were fitted with GPS collars. A total of 2,288 valid signals were analyzed (565 from males and 1,723 from females). In addition, 1,333 sighting records were collected from eight observation posts (480 in 2019, 670 in 2020 and 183 in 2021). We determined the movements and spatial distribution of translocated animals in the new habitat and estimated their home range sizes. Home range was calculated using the minimum convex polygon method, while the core area was calculated using the kernel density estimator method. The greatest straight-line distance from the acclimatisation enclosure was essentially the same for both sexes (average 6.0 km for males and 6.4 km for females). A non-significant relationship existed between the number of days in captivity and the greatest straight-line distance, as well as between days in captivity and the core area of the home range. The estimated home range of males was 12.8 km2 (range 0.2‒36.1), smaller than that of females (20.6 km2, range 0.4‒68.7), but this difference was not statistically significant. Observations made independently showed mostly herds of 4 to 6 individuals (52.3%), while large herds (≥ 10 individuals) were rare. Participation of translocated and resident animals in mixed herds was common during the monitoring period (62.3%). Our results showed that a high level of acceptance of the new habitat and social cohesion between translocated and resident animals was achieved. We believe that this is due to two main reasons: firstly, the long-term stay in a large acclimatisation enclosure prior to release and secondly, year-round supplemental feeding coupled with an abundant natural food supply in this unique forest area also contributed to successful acclimatisation. Keywords: Cervus elaphus; population; habitat; home range size; red deer; management

Droughts reshape apex predator space use and intraguild overlap.

Droughts are increasing in frequency and severity globally due to climate change, leading to changes in resource availability that may have cascading effects on animal ecology. Resource availability is a key driver of animal space use, which in turn influences interspecific interactions like intraguild competition. Understanding how climate-induced changes in resource availability influence animal space use, and how species-specific responses scale up to affect intraguild dynamics, is necessary for predicting broader community-level responses to climatic changes. Although several studies have demonstrated the ecological impacts of drought, the behavioural responses of individuals that scale up to these broader-scale effects are not well known, particularly among animals in top trophic levels like large carnivores. Furthermore, we currently lack understanding of how the impacts of climate variability on individual carnivore behaviour are linked to intraguild dynamics, in part because multi-species datasets collected at timescales relevant to climatic changes are rare. Using 11 years of GPS data from four sympatric large carnivore species in southern Africa-lions (Panthera leo), leopards (Panthera pardus), African wild dogs (Lycaon pictus) and cheetahs (Acinonyx jubatus)-spanning 4 severe drought events, we test whether drought conditions impact (1) large carnivore space use, (2) broad-scale intraguild spatial overlap and (3) fine-scale intraguild interactions. Drought conditions expanded space use across species, with carnivores increasing their monthly home range sizes by 35% (wild dogs) to 66% (leopards). Drought conditions increased the amount of spatial overlap between lions and subordinate felids (cheetahs and leopards) by up to 119%, but only lion-cheetah encounter rates were affected by these changes, declining in response to drought. Our findings reveal that drought has a clear signature on the space use of multiple sympatric large carnivore species, which can alter spatiotemporal partitioning between competing species. Our study thereby illuminates the links between environmental change, animal behaviour and intraguild dynamics. While fine-scale avoidance strategies may facilitate intraguild coexistence during periodic droughts, large carnivore conservation may require considerable expansion of protected areas or revised human-carnivore coexistence strategies to accommodate the likely long-term increased space demands of large carnivores under projected increases in drought intensity.

Dune Hares: Population Indices, Home Range Size, and Habitat Selection of the European Hare on a Danish Island.

Population indices, such as transect counts of animals, can provide important information concerning population changes over time. Moreover, data concerning the home range size and habitat selection of individuals can provide valuable insight into spatial requirements of animals and how they can adapt to variable environments. Here, we describe the population development of European hares (Lepus europaeus) and investigated home range sizes and habitat selection of six radio-tagged individuals on the small (80 ha) Danish Wadden Sea island Langli. The average minimum hare population density from 1983 to 1997 was 64 ± 36 (mean ± SD) hares/km2, with hare numbers varying among years and seasons. The average home range size was 23.3 (CI: 18.9-28.7) ha, which is comparable to agricultural areas of high structural diversity. Moreover, hare habitat selection was generally bimodal, with hares moving over larger areas and selecting marsh habitat for foraging during nighttime, and dune and grassland habitat for resting during daytime, especially during winter. Combined, our results indicate that hare abundance and space use in the dunal landscape of Langli Island were similar to agricultural areas of comparatively high habitat quality. Thus, dunal marsh landscapes offer high-quality habitat for hares and might be of importance as population strongholds at a time when hare populations are declining in many agricultural areas across Europe.

Immediate impacts of fire on koala movement in a fragmented landscape

Hazard reduction burns could pose a significant conservation challenge to threatened habitat specialists, such as koalas Phascolarctos cinereus. This study examines the immediate effects of a medium to hot hazard reduction burn on a small number of koalas occupying a fragmented agricultural area. Three koalas being monitored using GPS telemetry were inadvertently exposed to fire in a small strip of roadside vegetation in an agricultural landscape, providing an unexpected opportunity to assess their immediate responses to the fire. Nearly 81% of available trees were burnt to some degree, with 31% of tree foliage scorched up to 10.2m above the ground. The koalas reduced their home range sizes by 20–54% post-fire, where two avoided burnt areas while one remained within them. These findings highlight the importance of maintaining unburnt patches and corridors in fragmented landscapes and developing comprehensive conservation plans to mitigate the adverse effects of fire on koalas and other arboreal fauna.

Insights into the spatial ecology of the world’s most ancient dog: high-altitude movements of New Guinea dingoes

Knowledge of an animal’s activity patterns, home range size and space use is fundamental to understanding their basic ecology, and obtaining spatial data is an important research priority for newly discovered species, data-deficient species of conservation concern, or species of great scientific or public interest. Here we report the first spatial data obtained from wild-living dingoes near Puncak Jaya, New Guinea. Based on information from four dingoes monitored with GPS tracking collars between 2018 and 2022, we report that dingo home range sizes can be up to 128km2, dingoes travel up to 56.8km per day, and they utilise rainforest and alpine habitats up to 4,630m above sea level. Dingoes at the site regularly traversed steep, rocky and barren alpine mountain crevasses to access more fertile areas at lower altitudes on the other side. These results imply that New Guinea dingoes may have physiological and genetic adaptations that enable them to live in high-altitude low-oxygen environments similar to Himalayan wolves, Ethiopian wolves, and other canids found in high-altitude areas. As the first domesticated animal and the world’s most ancient dog, and given their historic and current cultural significance, their illusiveness in the wild, and their trophic position as the largest terrestrial predators on the second-largest island in the world, we believe that further research on the ecology of New Guinea dingoes will continue to reveal important insights valuable for our understanding of human and animal ecology in this global biodiversity hotspot.

Fully protected marine areas linked to reduced home ranges of fishes

AbstractHome range size is a fundamental trait that can affect the probability of fish being harvested and, at the same time, may be affected by fishing. The relationship between home range size and fishing will impact the effectiveness of fully protected areas (FPAs), as it will influence the number of fish moving into fished areas, affecting both spillover and edge effects. One hypothesis is that individuals within FPAs will present reduced home range size relative to individuals in fished areas. This pattern can be driven by demographic selection (e.g. fishing of individuals with large home ranges leaving the FPAs), improved habitat requiring less foraging movements, or behavioural changes associated with reduced fishing threats. To test the relationship between home range size and protection, we compiled 1143 individual‐level home range sizes based on acoustic tracking, covering 17 species from 11 FPAs in 7 countries, with information on distance from FPA borders. A dichotomic analysis (in/out of FPAs) did not support a significant change in the home range size between FPAs and fished areas. However, continuous analysis across the FPA borders demonstrated reduced home range size within the FPAs. We did not find an effect of FPA age or size on this pattern. While we cannot pinpoint the underlying mechanism for the pattern revealed, we suggest behavioural changes as the main driver for reduced home range within FPAs. This mechanism will lead to more resident populations within FPAs, reducing fishing mortality within FPAs yet limiting spillover benefits to adjacent fisheries.

Aggressive behavior as a predictor of home range size: findings from both range-restricted and widespread Darwin’s finch species

AbstractInformation about an animal’s home range (the geographical area in which it accesses resources for survival and reproduction) is vital broadly for understanding animal behavior and specifically for developing conservation management plans. Although personality traits—consistent individual differences in behavior across time and contexts—may affect an animal’s home range size, we still lack a breadth of empirical studies across systems to fully appreciate this influence. Here, we tested the relationship between behavioral responses and home range size in two Darwin’s finch species on Floreana Island: the critically endangered and range-restricted Medium Tree Finch (Camarhynchus pauper) and the common and widespread Small Ground Finch (Geospiza fuliginosa). Using a combination of rapid-assessment assays during both short-term captivity and in the field, we measured exploration and aggressiveness in males from both species. We then used radio telemetry to measure each bird’s home range size over a week-long period. We predicted that (1) fast-exploring individuals would have larger home ranges, and (2) more aggressive individuals would have smaller home ranges. We found that Medium Tree Finches had smaller home ranges than Small Ground Finches, that exploratory behavior was positively correlated with home range size only in Small Ground Finches, and that, in both species, individuals’ aggressiveness was negatively correlated with home range size, whereby the more aggressive individuals occupied smaller home ranges. We conclude that behavioral responses that align with major personality traits can predict home range size, which may provide an important tool for the conservation and management of endangered species when, for example, selecting individuals with different personality profiles for reintroduction.

Seasonal variation of home range size and habitat selection of elephants in the Kabompo landscape of Zambia

BackgroundMovements of large herbivores and habitat utilization provide critical information for ecological monitoring and conservation. However, such geospatial information rarely exists, especially in sub-Saharan Africa. This study aims to provide insight on seasonal variation of home range size and habitat utilization by African savanna elephants (Loxodonta africana) in Zambia’s Kabompo Landscape.MethodsTwo male sub-adult elephants (estimated age 10–15 years) were collared and monitored between March 2018 and December 2021 using the Geographic Position System (GPS) tracking devices. We used Minimum Convex Polygon (MCP), which uses the outermost points, to arrive at the largest home range of a study subject and the Kernel Density Estimator (KDE), which captures the intensity use of various parts of the home range. Distance from the river, elevation, slope, land cover type, fire intensity and Normalized Difference Vegetation Index (NDVI) were assessed against habitat selection by elephants using multinomial logistic regression.ResultsThe findings showed that the movements of the elephants were largely confined within the West Lunga National Park. The wet season had the largest home range (1720.8 km2) dominated by grassland, while the cold dry season had the smallest area of 931.8 km2. Elevation and land cover types had significant (p-value < 0.05) influence on home range across all the seasons. Other factors also had positive and negative impacts on the home range selection depending on the season.ConclusionsThe insights from this study can be exemplary relevant to conservation planning through monitoring seasonal movement of elephants.

Human-derived food shrinks home ranges and alters resource selection of mammals at the urban-wild interface

Protected lands are an important source of food, shelter, and reproductive opportunities for wildlife, especially in urban landscapes. When urban development abuts the edges of undisturbed ecosystems, synanthropic species can alter their foraging behaviors and movement to utilize human-supplemented resources throughout the urban-wild interface. Therefore, urban development on the edges of protected lands can have pronounced effects on animal movement and ecosystem functions. Iconic urban adaptive mesopredators such as northern raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana) often benefit from human-supplemented food sources such as unsecured garbage, pet food, and fresh water when available. To investigate how urban edges affect the movements of urban-adapted omnivores within conservation lands, we estimated home ranges and third-order resource selection of 27 raccoons and 12 opossums with GPS collars throughout the protected areas of northern Key Largo, FL, USA between April 2022–October 2023. The proportion of urban development in an individual's home range was the most influential factor associated with home range size, followed by species and sex. Individuals with greater proportions of residential neighborhoods and commercial areas in their home ranges exhibited smaller home ranges. Third-order resource selection functions identified both mesopredator species using residential and commercial land use areas more than they were available on the landscape. These results indicate that urban areas attract urban-adapted mesopredators from protected areas and result in smaller home ranges in the face of abundant human-derived food. Reduced home ranges on edges can support higher densities of animals, which may increase rates of disease transmission, especially when the urban borders support populations of feral domestic species. Shifting foraging behaviors from the protected areas to urban edges could have cascading downward effects if seed-dispersing roles are diluted. As urbanization increases and the distance between wild lands and human disturbance decreases, it is increasingly important to study the mechanisms of how urban development on the edges of protected areas affect the movement of wildlife.

Factors shaping home ranges of Eurasian lynx (Lynx lynx) in the Western Carpathians

Understanding how large carnivores utilize space is crucial for management planning in human-dominated landscape and enhances the accuracy of population size estimates. However, Eurasian lynx display a large inter-population variation in the size of home ranges across their European range which makes extrapolation to broader areas of a species distribution problematic. This study evaluates variations in home range size for 35 Eurasian lynx in the Western Carpathians during 2011–2022 based on GPS telemetry and explains how intrinsic and environmental factors shape lynx spatial behaviour when facing anthropogenic pressure. The average annual home range size of lynx ranged from 283 (± 42 SE) to 360 (± 60 SE) km2 for males and from 148 (± 50 SE) to 190 (± 70 SE) km2 for females, depending on home range estimator (95% MCP, KDE and AKDE). Females with kittens had smaller annual and summer home ranges compared to non-reproducing females and subadults had smaller home ranges compared to adults. Lynx home range size was explained by availability of roe deer, except for summer, when alternative prey was likely available. We also found clear evidence of human-induced changes in lynx home range size, in particular, forest cover significantly decreased the home range size of male lynx during summer while road density led to an expansion of both annual and summer lynx home ranges. Lynx exhibited consistent fidelity to their home ranges throughout consecutive seasons, showing no seasonal variations. Strong territoriality was observed among competing males maintaining relatively low home range overlaps and considerable distances between centres of activity. The most pronounced tendency for association was observed between males and females, maintaining relatively close proximity year-round. The insights into lynx spatial requirements provided by our study will greatly enhance the accuracy of population size estimates and effectiveness of mitigation measures across the Western Carpathians.

Postbreeding ecology of wood ducks in the Illinois River Valley

AbstractThe wood duck (Aix sponsa) consistently ranks within the top 5 harvested duck species for both Illinois and the Mississippi Flyway. While substantial research has been done on wood ducks, especially their breeding ecology, few studies have investigated the postbreeding ecology of the species. We captured and marked wood ducks with either a very high frequency (VHF) radio transmitter or a solar‐charged global system of mobile communication (GSM) transmitter during the postbreeding period from August through September 2018–2020. Capture locations were within the La Grange Pool of the Illinois River extending from near Pekin, Illinois to the La Grange Lock and Dam near Meredosia, Illinois, USA. We used conventional radio‐telemetry techniques to track wood ducks to determine cover type use, home range size, daily movement patterns, survival, and migration chronology. Home range size (95% minimum convex polygon) for wood ducks averaged 6,820 ± 572 ha (SE) and we did not find evidence for a difference by age, sex, or transmitter type. Daily movement distance in August (2,031 ± 51 m) was similar to daily movement distance in September (1,922 ± 44 m), but daily movement distances for August and September were less than daily movement distance for October (3,509 ± 53 m) and November (3,347 ± 106 m). Wood ducks primarily used wetlands with woody (45.0%) and emergent vegetation (40.4%), and the most commonly used wetland types by wood ducks were impounded wetlands (53.8%), lakes (17.6%), and ponds (10.7%). Model‐derived survival during the postbreeding period was 0.79 (95% CI = 0.74–0.84). Daily survival was positively related to increased river level and had a mean increase of 4.06 ± 0.67% for every 0.3‐m increase in the Illinois River level at low river levels (1.5–3.0 m) and a mean increase of 1.38 ± 0.32% for every 0.3‐m increase in the Illinois River level at high river levels (4.0–5.5 m). Average departure date of wood ducks leaving the Illinois River Valley was 27 October (range =13 August–15 December), and adult male wood ducks left the study area 11–16 days earlier than the other age and sex cohorts (H2 = 11.6, P = 0.01). Providing additional waterfowl sanctuaries that contain wooded wetlands, especially in years of low river levels, may increase survival for wood ducks during the postbreeding period.

Odor Fences Have No Effect on Wild Boar Movement and Home Range Size.

Wild boars are an opportunistic wildlife species that has successfully colonized the human-modified landscape in Europe. However, the current population boom has negative consequences, which result in a rapid increase in human-wildlife conflicts and disease transmission, including African swine fever (ASF). The increasing frequency of conflicts requires adequate solutions for these issues through various measures. Application of deterrents is a common non-lethal measure whose effects have been insufficiently verified until recently. Thus, this study aims to evaluate the effectiveness of odor fences, often applied as a barrier against wild boar movement. For this purpose, 18 wild boars were marked with GPS collars. After 22 days of initial monitoring, 12 sections of odor fences were installed on their home ranges. The monitored wild boars crossed the area 20.5 ± 9.2 times during the pre-installation period and 19.9 ± 8.4 times after the odor fence installation. Moreover, the average home range varied between 377.9 ± 185.0 ha before and 378.1 ± 142.2 ha after the odor fence installation. Based on GPS telemetry results, we do not support using odor repellent lines for crop protection or for limiting wild boar movement to lessen ASF outbreaks.

The Characteristics and Variation of the Golden Eagle Aquila chrysaetos Home Range

Satellite tracking allows for novel investigations into golden eagle home range characteristics. Understanding home range characteristics is important for conservation and for assessing the potential impact of landscape changes from forest planting, wind farms, etc. Small sample sizes, inconsistent definitions and methods restricted several previous studies. Our study involved 69 resident tagged eagles with over one year of data across five Scottish regions. Home range size was estimated from 95% isopleth contours extracted from Utilisation Distributions. Above a small threshold, estimated range size was not affected by the number of records but at least one year of data is required, largely because of the breeding and non-breeding seasonal differences. There were no significant range size differences between birds tagged as range holders and those previously tagged as nestlings. Across four regions, with considerable intra-regional variation, planar 95% isopleths did not differ (medians, km2): Argyll 58.9, Northwest Highlands 61.7, Northeast Highlands 89.3, South of Scotland 91.9. Ranges in the isolated Outer Hebrides region were exceptionally small, at 24.0 km2. Estimated range area was usually reduced to 70–80% of the planar area when restricted to usable habitat, as estimated by the Golden Eagle Topography (GET) model. Applying measures of known unsuitable habitat (closed-canopy commercial forest and wind turbines) further reduced usable open land. Loss of otherwise suitable habitat was substantially due to commercial forest. Larger ranges had larger extents of suitable habitat (according to GET), with no apparent optimum of preferred GET habitat. Range size was not different across a year between the sexes. Breeding ranges were smaller, and females’ breeding ranges were much smaller than those of males, but larger than males’ ranges in the non-breeding season. Breeding attempt duration was probably also influential. Our study provides novel insights into golden eagle home range characteristics and can guide further research and practical applications.

The influence of fence design on the movement patterns of eastern long‐necked turtles

AbstractFences disturb the movements of terrestrial species, altering migration patterns, limiting access to vital resources, and reducing genetic diversity. With almost 40% of the Earth's land surface converted for agriculture, farm fencing to protect crops and corral livestock is expected to stretch into the millions of kilometers. As semi‐terrestrial ectotherms, freshwater turtles are threatened by fences that limit access to resources and increase risks of desiccation, entanglement, and overheating, often resulting in death. To determine the effect of fences, we quantified the movement patterns for a population of eastern long‐necked turtles (Chelodina longicollis) inhabiting an agricultural landscape near Armidale, New South Wales, Australia from November 2022 to September 2023. There was considerable variation in the distance traveled, home range size, and movement corridor selection between turtles that was not explained by the morphological factors of size, mass, or the loss of a limb (likely due to predation attempts). On average, 38% ± 4.70 ( ± SE) of turtle movements were terrestrial (overland) during their active season (spring and summer) during which they encountered fences frequently because of a complex matrix of paddocks. Fence design dictated the distance turtles traveled to locate a suitable passage point. The majority of fences allowed turtles to pass (turtle‐friendly fences, 71.4% of total fence distance) as opposed to turtle‐unfriendly fences (28.6% of total fence distance). Turtles were required to travel almost 4 times the distance to locate a suitable crossing point (a gap or fault in the fence) when they encountered an unfriendly fence (85.32 m ± 29.81) compared to a turtle‐friendly fence (25.85 m ± 3.58). Our results highlight the need for land managers to avoid small‐diameter exclusion fencing and fence designs containing chicken wire that extend to or below ground level. In settings where small‐diameter wire fencing is required, we recommend the installation of turtle gates for small terrestrial fauna or elevating bottom wires at least 50 mm above ground level to facilitate fence permeability.

Home ranges, habitat selection, and energy expenditure of Strix varia (Barred Owls): Understanding the full diel cycle matters for enhancing urban landscapes

Abstract We integrated GPS and accelerometer data to examine habitat selection and energy expenditure patterns across the diel cycle in Strix varia (Barred Owls), addressing a critical gap in wildlife research that often overlooks activity during the “inactive” phase. Owls in Baton Rouge, Louisiana, selected forests with tall canopies and open understories, particularly in affluent neighborhoods, supporting the “luxury effect” in urban biodiversity. Nocturnal home ranges were larger (31.8 ha) compared to diurnal home ranges (8.9 ha), indicating broader habitat use at night. The total area of preferred nocturnal habitat was 33% of the Baton Rouge study area, whereas preferred diurnal habitat comprised only 5%. Energy expenditure was inversely related to preference in nocturnal home ranges but increased with preference in diurnal home ranges. Our models were validated using independent data from Clemson, South Carolina, supporting the robustness of our analysis and revealing generalities in owl habitat selection across these regions. This research contributes to a deeper understanding of urban ecology, highlighting habitat components preferred by owls and possibly other forest-dwelling species. It emphasizes the difference in nocturnal and diurnal home range sizes, the scarcity of daytime refuges for S. varia in urban landscapes, and the variation in energy expenditure in preferred habitats. Our findings advocate for urban designs that accommodate wildlife activity throughout the day and night, and highlight the positive correlation between preferred owl habitat and affluent neighborhoods, underscoring the need for equitable distribution of green spaces to foster biodiversity across socioeconomic gradients. These insights will help develop strategies to enhance the ecological value of urban environments and the conservation of S. varia and associated forest-dwelling species in rapidly urbanizing areas.

Aspects of Movement Ecology and Habitat Use of Migratory Raptors Using Satellite Telemetry from India to Central Asia

Single individuals of the Greater Spotted Eagle (Clanga clanga), Indian Spotted Eagle (Clanga hastata), Tawny Eagle (Aquila rapax), Western Marsh Harrier (Circus aeruginosus), and two Pallid Harriers (Circus macrourus) were deployed with satellite transmitters in 2021 to study their home ranges, habitat associations, movement, and migration patterns. Data were collected for a combined number of 2291 days, providing 84,544 locations. Home ranges were calculated as kernel utilization distributions and expressed as 95% KDE and core areas as 50% KDE. Overall, eagles had larger home ranges (mean ± SD) of 942.70 ± 937.83 km2 compared to harriers, 43.84 ± 35.55 km2. Among eagles, the Greater Spotted Eagle had the largest home-range size of 2147.03 km2 calculated in Kazakhstan, while the female Pallid Harrier had the smallest home range of 5.74 km2 in Russia. Daily and monthly distances varied among eagles and harriers. The female Pallid Harrier covered the longest average monthly distance of 8585.43 ± 11,943.39 km, while the shortest monthly distance of 1338.22 ± 716.38 km was traveled by the Indian Spotted Eagle. All tagged birds migrated toward higher latitudes in the Northern hemisphere, except the Indian Spotted Eagle, which migrated to Pakistan. The male Western Marsh Harrier covered the longest migration distance in a shorter span of time, while the female Pallid Harrier took the longest to cover its migration distance. Overall, the daily distance covered during migration varied from 115.09 km traveled by the Indian Spotted Eagle to an overwhelming distance of 2035.85 km covered by the male Western Marsh Harrier. Scrubs, water bodies, croplands, and settlements were important habitat features associated with eagles, while croplands, open scrub, and built-up areas were associated with the female Pallid Harrier. The male Western Marsh Harrier was found to be primarily associated with saltpans and salt-affected areas having emergent vegetation. This study presents new insights into the movement and spatial ecology of long-distance migrant raptors that winter in Western India. We provide preliminary support for the use of the Western Circum–Himalayan Corridor as one of the important corridors of the Central Asian Flyway that warrants much appreciation among the current set of flyway corridors.