Dynamic Brownian Bridge Movement Models Research Articles

Female Deer Movements Relative to Firearms Hunting in Northern Georgia, USA.

Perceived risk associated with hunters can cause white-tailed deer (Odocoileus virginianus) to shift their activity away from key foraging areas or alter normal movements, which are important considerations in managing hunting and its effects on a population. We studied the effects of seven firearms hunts on the movements of 20 female deer in two Wildlife Management Areas within the Chattahoochee National Forest of northern Georgia, USA, during the 2018-2019 and 2019-2020 hunting seasons. Deer populations and the number of hunters in our study area have declined significantly since the 1980s. In response, hunting regulations for the 2019-2020 hunting season eliminated opportunities for harvesting female deer. To evaluate the indirect effects of antlered deer hunting on non-target female deer, we calculated 90% utilization distributions (UDs), 50% UDs, and step lengths for pre-hunt, hunt, and post-hunt periods using the dynamic Brownian bridge movement model. Data included 30 min GPS locations for 44 deer-hunt combinations. Pre-hunt 50% UDs (x- = 7.0 ha, SE = 0.4 ha) were slightly greater than both hunt (x- = 6.0 ha, SE = 0.3 ha) and post-hunt (x- = 6.0 ha, SE = 0.2 ha) 50% UDs (F = 3.84, p = 0.03). We did not detect differences in step length, nor did we detect differences in size or composition of 90% UDs, among the periods. Overall, our results suggest that the low level of hunting pressure in our study area and lack of exposure to hunters led to no biologically significant changes in female deer movements. To the extent of the findings presented in this paper, adjustments to the management of hunting in our study area do not appear to be necessary to minimize hunting-related disturbances for female deer. However, managers should continue to consider female deer behavior when evaluating future changes to hunting regulations.

GPS Tracking Reveals the White-Tailed Eagle Haliaeetus albicilla as an Ambassador for the Natura 2000 Network

The Natura 2000 network of protected areas is the backbone of species conservation in the European Union. We investigated whether Austrian-hatched white-tailed eagles (Haliaeetus albicilla) make particular use of this multinational network during their natal dispersal, and what habitats were of importance to the eagles. We analyzed the utilization distribution of 907,466 GPS locations from 38 dispersing white-tailed eagles using a dynamic Brownian Bridge Movement Model. Eagles ranged over a huge area of central-eastern Europe. Natura 2000 sites overlapped with 67% of the resulting 50% isopleth; i.e., a high probability of utilization of Natura 2000 areas by white-tailed eagles was found. White-tailed eagles used wetlands, waterbodies, and deciduous forests adjacent to wet habitats disproportionately often. Coniferous forests and settlements were avoided. Anthropogenically caused mortalities hardly occurred within Natura 2000 sites. Our study suggests that the Natura 2000 network is a crucial tool for conserving the white-tailed eagle. This top predator is an ambassador for the Natura 2000 idea during all life stages, and should continue to be a conservation priority of the network.

Conservation of Bewick’s swans (Cygnus columbianus bewickii): Insights from the identification of critical stopover sites and migration corridors

Migratory birds face diverse threats during migration. Critical stopover sites (CSSs) are essential refueling and resting sites for migratory birds that ensure their complete migration and survival. Therefore, identifying bird migration patterns, routes, and critical habitats is vital for conservation. From 2018–2022, we deployed satellite tracking devices on 30 Bewick’s swans (Cygnus columbianus bewickii) wintering in China to determine their migration routes. Using a dynamic Brownian bridge movement model, we identified migration corridors, core movement areas, and CSSs for Bewick’s swans. Combining protected area databases and human settlement types, we further assessed the swans’ conservation status and human impacts on CSSs. The results showed that Bewick’s swans migrated north from their wintering grounds using one of three routes (west, middle, and east), passing through Mongolia to reach the Russian Arctic (breeding grounds) in spring. They followed similar routes during autumn to return to wintering grounds. We found a new middle route within the East Asian–Australasian Flyway (EAAF) and several northward expanded wintering sites. Our study revealed similarities and differences in the spring and autumn migrations, with longer stopover durations in spring due to migration strategies and ice conditions. Moreover, our findings identified the Inner Mongolia region, the Songnen Plain, the Bohai Rim of China, and the main streams of the Lena River and the Ob River of Russia as CSSs for Bewick’s swans. However, the conservation status of the CSSs was relatively low; and the situation was more severe in spring than in autumn, only 4.3% of the total area was protected, likely due to the distribution of farmland and urban areas. Specifically, 14.3% of the CSSs in China were in urban areas during spring, while in Mongolia and Russia this figure was less than 1%. Therefore, it is necessary to balance waterbird conservation with sustainable agriculture and urban development. This research contributes to our understanding of the migratory ecology of Bewick’s swans wintering in China. The identified migration corridors and CSSs are crucial for the future conservation of swans along the EAAF.

Spatial Ecology of an Arboreal Iguana (Oplurus cyclurus) in a Treeless Landscape.

Understanding the spatial ecology of species has important implications for conservation, as it helps identify suitable habitats and minimum requirements for biodiversity monitoring and management. The spiny-tailed lizard Oplurus cyclurus is a widespread endemic iguanid occurring in dry areas of southern and western Madagascar. While the species is known to be mostly arboreal, populations of the Isalo sandstone massif suggest local adaptation to a less forested savannah and a more exposed habitat. We radio-tracked 19 spiny-tailed lizards to investigate the species' rock-dwelling behaviour and spatial ecology at Isalo National Park. Tracked individuals showed high site and burrow fidelity, and a basking behaviour mostly tied to the accessibility of their burrow, the time of day, and their life stage. Activity peaked during the sunniest hours, while juveniles were more active than adults with unfavourable weather conditions. Despite high burrow fidelity, lizards used shelters non-exclusively, regularly changing (approx. once a week) with neighbouring burrows (average distance between burrows = 13.6 m). However, there was no obvious relation between lizards' body and/or tail size and the width and depth of selected burrows. Dynamic Brownian Bridge Movement Models estimated frequented areas over 247.8 m2 (95% isopleth), where territorial overlap is common. Our results challenge the notion that burrow-site fidelity is the sole driving factor behind space utilization in the studied population. We argue that the apparently unusual saxicolous habits imposed by habitat features (the absence of trees) may lead to local behavioural adjustments influencing antipredatory and foraging strategies, as well as intraspecific interactions.

Potential Effects of Habitat Change on Migratory Bird Movements and Avian Influenza Transmission in the East Asian-Australasian Flyway

Wild waterbirds, and especially wild waterfowl, are considered to be a reservoir for avian influenza viruses, with transmission likely occurring at the agricultural-wildlife interface. In the past few decades, avian influenza has repeatedly emerged in China along the East Asian-Australasian Flyway (EAAF), where extensive habitat conversion has occurred. Rapid environmental changes in the EAAF, especially distributional changes in rice paddy agriculture, have the potential to affect both the movements of wild migratory birds and the likelihood of spillover at the agricultural-wildlife interface. To begin to understand the potential implications such changes may have on waterfowl and disease transmission risk, we created dynamic Brownian Bridge Movement Models (dBBMM) based on waterfowl telemetry data. We used these dBBMM models to create hypothetical scenarios that would predict likely changes in waterfowl distribution relative to recent changes in rice distribution quantified through remote sensing. Our models examined a range of responses in which increased availability of rice paddies would drive increased use by waterfowl and decreased availability would result in decreased use, predicted from empirical data. Results from our scenarios suggested that in southeast China, relatively small decreases in rice agriculture could lead to dramatic loss of stopover habitat, and in northeast China, increases in rice paddies should provide new areas that can be used by waterfowl. Finally, we explored the implications of how such scenarios of changing waterfowl distribution may affect the potential for avian influenza transmission. Our results provide advance understanding of changing disease transmission threats by incorporating real-world data that predicts differences in habitat utilization by migratory birds over time.

Sharing habitat: Effects of migratory barnacle geese density on meadow breeding waders

1.Following targeted conservation actions most goose populations have increased. The growing goose populations caused an increase in human-wildlife conflicts and have the potential to affect nature values. As meadow birds, including meadow-breeding waders, were declining throughout Western Europe, the possible negative effect of rising numbers of foraging barnacle geese on their breeding success has been questioned.2.We used GPS-transmitter data to measure the density of foraging barnacle geese during daylight hours. Using dynamic Brownian Bridge Movement Models (dBBMM), we investigated the effect of barnacle goose density on the territory distribution of five wader species, and on nest success of the locally common Northern lapwing. We used model selection methods to identify the importance of barnacle goose density related to other environmental factors.3.Our results showed an insignificant positive association between barnacle goose density and nest territory density of the Northern lapwing and common redshank. Barnacle goose density had no influence on territory selection of godwit, oystercatcher and ringed plover. We did, however, find a negative correlation between barnacle geese density and the nest success of the Northern Lapwing.4.We infer that either barnacle goose foraging leads to improved territory conditions for some wader species, or that both barnacle geese and waders prefer the same type of habitat for foraging and nesting. Higher barnacle goose density was correlated with fewer Northern lapwing nests being successful.5.Synthesis and application: Experimental research is needed to disentangle the causal chain, but based on our observational findings, we suggest to increase water logging that may attract both barnacle geese and wader species. Further investigation on the effects of barnacle geese on wader species is necessary to identify the cause of the negative correlation between barnacle geese density and nest success of lapwings; nest protection experiments could give further insight.

Migration routes and stepping stones along the western flyway of Lesser White-fronted Geese (Anser erythropus)

Summary In 2015 and 2016 four Lesser White-fronted Geese (Anser erythropus), a globally threatened species, were caught and tagged during spring migration representing nearly 10% of the entire Swedish breeding population at the time. Two of the birds were followed over more than one season. Tracking data revealed an unexpected wide network of migration corridors and staging sites. Autumn and spring migration differed by stepping-stone sites and migration speed. So far unknown key stopover sites were discovered in Denmark, northern Germany, and Sweden. By using dynamic Brownian bridge movement models, the potential areas that Lesser White-fronted Geese used during migration are described and conservation implications spotlighted. This study provides another important piece of the puzzle describing the migration of Lesser White-fronted Geese in Western Europe.

Movement and ranging behaviour of long-nosed potoroos (Potorous tridactylus) in south-west Victoria, Australia

Context A comprehensive understanding of movements and space use can underpin the effective management of threatened species. GPS dataloggers can collect large amounts of high-quality movement data, and recent advances in statistical approaches allow for robust estimates of home range size to be generated. Until recently, technological and practical constraints have generally restricted the collection of movement data via GPS dataloggers to larger species. However, reductions in the size and weight of GPS dataloggers now allow for this technology to be applied to smaller species. Aims The aim of this study was to describe the home range and movement patterns of a nationally vulnerable, native Australian ground-dwelling mammal, the long-nosed potoroo (Potorous tridactylus), in south-west Victoria, mainland Australia. Methods We attached GPS dataloggers to 40 long-nosed potoroos between 2020 and 2022 and estimated home range size using dynamic Brownian Bridge movement models. We evaluated the influence of physiological factors such as body mass and sex on home range size and described patterns of home range overlap between and within sexes. Key results Mean home range sizes were estimated to be 13.73 ha (95% CI: 10.9–16.6) and 6.67 ha (95% CI: 5.49–7.85) for males and females respectively. Home range size scaled with body mass in males but not females, and ranges were largely overlapping – although there was some evidence of intrasexual spatial partitioning of core range areas in females. Conclusions Ours is the first application of GPS dataloggers to this species, and our home range estimates are over twice as large as other reported estimates for mainland Australia. Long-nosed potoroos may range across larger areas than previously predicted on mainland Australia. Implications This knowledge may be used to optimise the management of long-nosed potoroo populations before and after fire – a key threatening process for this species. Our study highlights the value of integrating GPS dataloggers and robust home range estimators when describing the movement ecology of a population.

Natal Dispersal of Eastern Imperial Eagles: Preliminary Results For the Central European Population

The Central European Population of the Eastern Imperial Eagle (Aquila heliaca) is located on its most western global distribution edge. After a strong decline in the last two centuries, the population recovered in the past decades not least due to extensive protection measurements. Conservation and scientific programs on international and national level were implemented in several countries, especially in Hungary, Slovakia, Austria, Czech Republic, and Serbia. In frame of these activities imperial eagle were tagged by satellite transmitter since 2003 in several projects by different organisations of the region. In the current presentation we show preliminary results of an analysis of the natal dispersal movements of the immature birds of this residential population of Eastern Imperial Eagles. Therefore, more than 14 million data points of more than 130 individuals were available and analysed. We defined start of natal dispersal as the point when the young birds left their natal territory (5 km from natal nest) for at least 10 consecutive days. Because of high individual variability, we decided to classify the end of dispersal manually as the time the bird became territorial for the first time. We analysed movement pattern for the whole period of natal dispersal as well as for different life stages/age classes. Therefore we distinguished between breeding (1.2–30.9) and non-breeding season (1.10–30.2) for each year of life of the birds. It turns out that daily travel ranges are higher during the breeding season than outside the breeding season and that activity decreases over the years until the birds start establishing a territory. Furthermore, we estimate utilization distribution (UD) by calculating a dynamic Brownian Bridge Movement Model (dBBMM). Therefor in a first step, a dBBMM was calculated for each single individual. Those individual UDs were summarised up by using days of tracking as weight. The resulting UD gives an overview of distribution and space use of immature Eastern Imperial Eagles. It shows that while wide explorative flights of single birds occur, the majority of the birds stays mainly in Central Europe within the range of the breeding distribution of the population. Additional, there is a connection to the western parts of Greece and the island of Crete. The results help to enhance knowledge about habitat use and identify hotspots for further conservation efforts.

Identifying seasonal differences in migration characteristics of Oriental white stork (Ciconia boyciana) through satellite tracking and remote sensing

Migratory species interact with different ecosystems in different regions during migration, making them more environmentally sensitive and therefore more vulnerable to extinction. Long migration routes and limited conservation resources desire clear identification of conservation priorities to improve the allocation efficiency of conservation resources. Clarifying the spatio-temporal heterogeneity of the utilization intensity during migration is an effective way to guide the conservation areas and priority. 12 Oriental White Storks (Ciconia boyciana), listed as an “endangered” species by the IUCN, were equipped with satellite-tracking loggers to record their hourly location throughout the year. Then, combined with remote sensing and dynamic Brownian Bridge Movement Model (dBBMM), characteristics and differences between spring and autumn migration were identified and compared. Our findings revealed that: (1) the Bohai Rim has always been the core stopover area for the Storks’ spring and autumn migration, but the utilization intensity has spatial differences; (2) differences in habitat selection resulted in differences in the Storks’ spatial distribution, thus affecting the efficiency of existing conservation systems; (3) the shift of habitat from natural wetlands to artificial surfaces calls for the development of eco-friendly land use mode; (4) the development of satellite tracking, remote sensing, and advanced data analysis methods have greatly facilitated movement ecology, even though they are still under development.

Phenology‐specific space use by Rio Grande wild turkeys

AbstractConservation of wildlife populations necessitates identifying patterns in space use because fitness requirements influence resource selection; however, details on how phenology affects space use are often only cursorily addressed during development of space‐ and resource‐use estimates. Moreover, space‐use assessments often aggregate distinct, phenology‐specific behaviors into generalized realizations of biological processes, such as reproduction. Therefore, to improve the relevance and accuracy of biological inferences for wild turkey (Meleagris gallopavo) space use at the population level, we defined 12 distinct phenology‐specific periods to compare and contrast variations in space‐use estimates. We calculated 1,568 individual space‐use estimates using dynamic Brownian Bridge movement models for Rio Grande wild turkeys (M. g. intermedia; n = 255 females) across Texas, USA, during 2012−2018. Females in each pre‐laying state used larger areas than during all other phenological states, suggestive of exploratory movements related to reproductive activities and resource acquisition. Incubation core areas were consistently <1.5 ha and incubation range sizes ranged from 10 ha to 48 ha. Core area and range sizes during the brooding period doubled from 15 days after hatch (3.1 ha and 42 ha) to 30 days after hatch (6.5 ha and 89 ha). Post‐breeding and wintering period ranges were >30% smaller than reproductive period ranges. Mean daily distance traveled was similar across phenological states except during incubation and brooding periods. Our results indicate that examining wild turkey space use at identifiable, phenology‐specific temporal scales will help mitigate against biases in estimates of resource selection based on arbitrary phenology definitions that aggregate data across multiple, distinct, phenological states.

Factors influencing Arctic brown bear annual home range sizes and limitations of home range analyses

Home range size is a basic ecological index related to individual's realized niche. Its size can be influenced by body size, sex, maternal status, population density, habitat productivity, spatiotemporal variation of resources, climate, predation risk, and disturbance. Home range estimation can also be greatly affected by methodology and sampling regime. We used Global Positioning System collar data to assess what factors influenced the size of annual home ranges (space use during a single active season) of 28 female and 8 male brown bears (Ursus arctos) that denned in the Brooks Range of northcentral Alaska, USA, from 2014 to 2017. We used 2 methods to estimate annual home ranges, the Kernel Density Estimate (KDE) and the dynamic Brownian Bridge Movement Model (dBBMM). Contrary to expectations, we did not find that larger bodied bears of the same sex had larger annual home ranges. Annual home ranges of male bears (mean [standard deviation]; 504 [312] km2 and 3,886 [4,279] km2, using dBBMM and KDE, respectively) were 3.7–9.4 times larger than that of females (135 [86] km2 and 411 [738] km2, respectively). We found that greater chum salmon (Oncorhynchus keta) consumption was associated with larger annual home ranges for both sexes. In contrast, coastal brown bear populations that consume high levels of salmon often have small annual home ranges. We suggest that the relatively long distance (up to 100 km) between salmon streams and another key resource, denning habitat, is a reason for the positive association between salmon consumption and annual home range size. Although age was not in our top model for annual home range size, younger bears tended to have larger annual home ranges. We documented the fact that individuals of both sexes had the largest annual home ranges of any we could find for brown bears worldwide, using a traditional measure of space use (KDE). However, very large annual home ranges were associated with nonlocalized movements and the alternative method (dBBMM) to delineate these ranges provided more realistic range estimates. We discuss options and limitations of estimating space use and recommend caution when comparing space use between studies. With large-scale industrial infrastructure approved for development in this previously undeveloped region, the size and drivers of bear annual home ranges have numerous management implications. Brown bears with large annual home ranges in northcentral Alaska, where primary productivity is relatively low and denning habitat often far from salmon-bearing streams, are likely to move outside conservation units and encounter more risks as they interact with human infrastructure.

Seasonal differences of the Milu's home range at the early rewilding stage in Dongting Lake area, China

The study of home range utilization of rewilded animals is important for informed reintroduction management. Sixteen Milu adult individuals (5♂11♀) were reintroduced from Jiangsu Dafeng Milu National Nature Reserve to Hunan East Dongting Lake National Nature Reserve on February 28, 2016, out of which 11 Milu individuals (1♂10♀) were wearing GPS satellite tracking collars. Subsequently, with the aid of GPS collar technology, combined with on-ground tracking observations, we tracked the reintroduced Milu for one year from March 2016 to February 2017. We used the dynamic Brownian Bridge Movement Model to estimate the individual home range of the 10 rewilded Milu (1♂9♀, 1 female individual was eliminated because its collar fell off) and seasonal home range of 5 rewilded female Milu (all tracked for up to one year). 95% level represented the home range, and 50% level represented the core areas. Temporal variation in normalized difference vegetation index were used to quantify changes in food availability. We also quantified resource use of rewilded Milu by calculating the selection ratio for all habitats within their core areas. The results showed that: (1) a total of 52,960 coordinate fixes were collected; (2) during the early stage of rewilding, the average home range size of the rewilded Milu was 17.62 ± 3.79 km 2 and the average core areas size was 0.77 ± 0.10 km 2 ; (3) the annual average home range size of the female deer was 26.08 ± 5.21 km 2 and the annual average core areas size was 1.01 ± 0.14 km 2 at the early stage of rewilding; (4) during the early stage of rewilding, the home range and core areas of the rewilded Milu were significantly affected by season, and the difference between summer and winter was significant (home range: p = 0.003; core areas: p = 0.008); (5) home range and core areas of the rewilded female deer in the Dongting Lake area in different seasons showed significant negative correlation with NDVI (home range: p = 0.000; core areas: p = 0.003); (6) Most rewilded female Milu showed a high preference for farmland in all seasons except winter, when they focused on using lake and beach. The home range of the rewilded Milu in the Dongting Lake area at the early stage of rewilding experienced significantly seasonal changes. Our study reveals seasonal differences in the home ranges of rewilded Milu and the resource use strategies of individual Milu in response to seasonal changes. At last, we put forward the following management recommendations: (1) to establish habitat islands; (2) to implement community co-management; (3) to reduce human disturbance; (4) to strengthen population monitoring for formulating species conservation plans. • This is the first time in China to implement ex situ field release of Milu. • dBBMM model is hardly limited by locus autocorrelation and sample size. • The sample size of this study was sufficient and the data were informative.

Environmental and anthropogenic influences on movement and foraging in a critically endangered lemur species, Propithecus tattersalli: implications for habitat conservation planning

BackgroundWildlife conservation often focuses on establishing protected areas. However, these conservation zones are frequently established without adequate knowledge of the movement patterns of the species they are designed to protect. Understanding movement and foraging patterns of species in dynamic and diverse habitats can allow managers to develop more effective conservation plans. Threatened lemurs in Madagascar are an example where management plans and protected areas are typically created to encompass large, extant forests rather than consider the overall resource needs of the target species.MethodsTo gain an understanding of golden-crowned sifaka (Propithecus tattersalli) movement patterns, including space use and habitat selection across their range of inhabited forest types, we combined behavior data with Dynamic Brownian Bridge Movement Models and Resource Selection Functions. We also examined the influence of abiotic, biotic, and anthropogenic factors on home range size, movement rates, and foraging patterns.ResultsWe found that home range size and movement rates differed between seasons, with increased core area size and movement in the rainy season. Forest type also played a role in foraging behavior with sifaka groups in the humid forest avoiding roads in both seasons, groups in the dry deciduous forest avoiding road networks in the rainy season, and groups in the moderate evergreen forest displaying no selection or avoidance of road networks while foraging.ConclusionOur study illustrates the importance of studying primate groups across seasons and forest types, as developing conservation plans from a single snapshot can give an inaccurate assessment of their natural behavior and resources needs of the species. More specifically, by understanding how forest type influences golden-crowned sifaka movement and foraging behavior, conservation management plans can be made to the individual forest types inhabited (dry deciduous, moderate evergreen, humid, littoral, etc.), rather than the region as a whole.

African wild dog movements show contrasting responses to long and short term risk of encountering lions: analysis using dynamic Brownian bridge movement models

BackgroundPrey depletion is a threat to the world’s large carnivores, and is likely to affect subordinate competitors within the large carnivore guild disproportionately. African lions limit African wild dog populations through interference competition and intraguild predation. When lion density is reduced as a result of prey depletion, wild dogs are not competitively released, and their population density remains low. Research examining distributions has demonstrated spatial avoidance of lions by wild dogs, but the effects of lions on patterns of movement have not been tested. Movement is one of the most energetically costly activities for many species and is particularly costly for cursorial hunters like wild dogs. Therefore, testing how top-down, bottom-up, and anthropogenic variables affect movement patterns can provide insight into mechanisms that limit wild dogs (and other subordinate competitors) in resource-depleted ecosystems.MethodsWe measured movement rates using the motion variance from dynamic Brownian Bridge Movement Models (dBBMMs) fit to data from GPS-collared wild dogs, then used a generalized linear model to test for effects on movement of predation risk from lions, predictors of prey density, and anthropogenic and seasonal variables.ResultsWild dogs proactively reduced movement in areas with high lion density, but reactively increased movement when lions were immediately nearby. Predictors of prey density had consistently weaker effects on movement than lions did, but movements were reduced in the wet season and when dependent offspring were present.ConclusionWild dogs alter their patterns of movement in response to lions in ways that are likely to have important energetic consequences. Our results support the recent suggestion that competitive limitation of wild dogs by lions remains strong in ecosystems where lion and wild dog densities are both low as a result of anthropogenic prey depletion. Our results reinforce an emerging pattern that movements often show contrasting responses to long-term and short-term variation in predation risk.

How do King Cobras move across a major highway? Unintentional wildlife crossing structures may facilitate movement.

Global road networks continue to expand, and the wildlife responses to these landscape‐level changes need to be understood to advise long‐term management decisions. Roads have high mortality risk to snakes because snakes typically move slowly and can be intentionally targeted by drivers.We investigated how radio‐tracked King Cobras (Ophiophagus hannah) traverse a major highway in northeast Thailand, and if reproductive cycles were associated with road hazards.We surveyed a 15.3 km stretch of Highway 304 to determine if there were any locations where snakes could safely move across the road (e.g., culverts and bridges). We used recurse analyses to detect possible road‐crossing events, and used dynamic Brownian Bridge Movement Models (dBBMMs) to show movement pathways association with possible unintentional crossing structures. We further used Integrated Step Selection Functions (ISSF) to assess seasonal differences in avoidance of major roads for adult King Cobras in relation to reproductive state.We discovered 32 unintentional wildlife crossing locations capable of facilitating King Cobra movement across the highway. While our dBBMMs broadly revealed underpasses as possible crossing points, they failed to identify specific underpasses used by telemetered individuals; however, the tracking locations pre‐ and post‐crossing and photographs provided strong evidence of underpass use. Our ISSF suggested a lower avoidance of roads during the breeding season, although the results were inconclusive. With the high volume of traffic, large size of King Cobras, and a 98.8% success rate of crossing the road in our study (nine individuals: 84 crossing attempts with one fatality), we strongly suspect that individuals are using the unintentional crossing structures to safely traverse the road.Further research is needed to determine the extent of wildlife underpass use at our study site. We propose that more consistent integration of drainage culverts and bridges could help mitigate the impacts of roads on some terrestrial wildlife.

Multi-year assessment of immature bull shark Carcharhinus leucas residency and activity spaces in an expansive estuarine nursery

Although portions of the Indian River Lagoon (IRL), Florida (USA), serve as essential fish habitat for US Atlantic coast bull sharks Carcharhinus leucas, past studies were short-term (days to months) and encompassed only small parts of this expansive estuarine system. In this study, 29 immature bull sharks were tracked in the IRL between Port St. John and Port Salerno, Florida, and in adjacent shelf waters for up to 4 yr using passive acoustic telemetry. Dynamic Brownian bridge movement models showed small daily (50% utilization distribution [UD] = 1.00 km2, 95% UD = 4.36 km2) and monthly (50% UD = 4.88 km2, 95% UD = 24.67 km2) mean activity spaces that seasonally shifted (October-March) to include adjacent coastal waters. Tracked bull sharks were found to display residency in the IRL and in distinct subregions of the system. Analysis confirmed that bull shark nursery habitat extends south of Sebastian Inlet to Port Salerno, approximately 86 km farther south than previously described, and that adjacent shelf waters, which had not been studied, are important to immature bull sharks during cooler months. This study provides the first multi-year assessment of bull shark space use in the IRL, with improved resolution and over a greater expanse of the system than past studies. These movement data will be important to understanding how young bull sharks may be affected by anthropogenic stressors in this highly impacted lagoonal estuary.

Fishing for Feral Cats in a Naturally Fragmented Rocky Landscape Using Movement Data

Feral cats are one of the most damaging predators on Earth. They can be found throughout most of Australia’s mainland and many of its larger islands, where they are adaptable predators responsible for the decline and extinction of many species of native fauna. Managing feral cat populations to mitigate their impacts is a conservation priority. Control strategies can be better informed by knowledge of the locations that cats frequent the most. However, this information is rarely captured at the population level and therefore requires modelling based on observations of a sample of individuals. Here, we use movement data from collared feral cats to estimate home range sizes by gender and create species distribution models in the Pilbara bioregion of Western Australia. Home ranges were estimated using dynamic Brownian bridge movement models and split into 50% and 95% utilisation distribution contours. Species distribution models used points intersecting with the 50% utilisation contours and thinned by spacing points 500 m apart to remove sampling bias. Male cat home ranges were between 5 km2 (50% utilisation) and 34 km2 (95% utilisation), which were approximately twice the size of the female cats studied (2–17 km2). Species distribution modelling revealed a preference for low-lying riparian habitats with highly productive vegetation cover and a tendency to avoid newly burnt areas and topographically complex, rocky landscapes. Conservation management can benefit by targeting control effort in preferential habitat.

Movements of a male greater spotted eagle (Clanga clanga) during its 2nd and 3rd calendar years

Abstract The greater spotted eagle (Clanga clanga) is poorly known compared to other European eagles. We tracked an immature greater spotted eagle during 2018–2020 within the eastern European part of the species’ distribution, west of the Ural Mountains. Because so little is published about the annual movements of this species, especially from that region, tracking data from this single individual are valuable. 95% kernel density estimator (KDE) range sizes for the two complete winters in Yemen were 4,009 km2 (2018), 1,889 km2 (2019); 95% dynamic Brownian bridge movement models (dBBMM) encompassed 1,309 km2 (2018) and 1,517 km2 (2019). It returned to the same wintering area every year. During summer 2018, it settled into a small area (95% KDE = 126 km2; 95% dBBMM = 21 km2) near Birsk, eastern European Russia; in 2019 it wandered over a huge area (95% dBBMM = 66,304 km2) of western Kazakhstan and southern Russia, south west of Yekaterinburg. Spring migration 2018 was west of the Caspian Sea; during 2019 it was east of it. Mean speed of spring migration was 160±120 km/day during 2018, and 132±109 km/day during 2019. Autumn migration passed east of the Caspian in both years, and the mean speed of migration was 62 ± 78 km/day in 2018, and 84 ± 95 km/day in 2019. During both spring and autumn migrations, the eagle made stopovers, mostly lasting 1–2 days. The eastern Alborz Mountains in northeastern Iran appeared to be an important stopover locale, where autumn stopovers lasted 19 days (2018) and 27 days (2019). These and other data suggest that most greater spotted eagles that spend summers west of about 42°E, winter in southern Europe, Asian Turkey, the Levant and Africa, and those that summer to the east of that meridian winter in southern Asia, including Arabia.

Space use and activity of Boiga cyanea – A major songbird nest predator in a seasonal tropical forest in Thailand

Predator-prey interactions are fundamental drivers of population dynamics. Studying both predator and prey species simultaneously yields particularly useful insights into these complex interactions. Despite being significant, widespread avian nest predators, Southeast Asian snakes are rarely simultaneously studied in relation to avian prey. The Green Cat Snake Boiga cyanea is a primary nest predator, estimated to be responsible for 17–33% of forest songbird nest depredations in Northeast Thailand. We explored both diurnal and nocturnal movements of 14 (5 male, 9 female) adult B. cyanea with radio-telemetry for an average of 68 ± 16 days per individual, between 21 October 2017 and 8 June 2019 in the dry evergreen forest of the Sakaerat Biosphere Reserve (SBR). We quantified horizontal movements (m) and area of space use (ha) and activity through motion variance (Ϭ m 2 ) during the study period using dynamic Brownian Bridge Movement Models (dBBMMs) and reported our findings within the context of a simultaneously run avian nest monitoring study initiated in 2013 within the same forest. On average, adult B. cyanea moved 56.4 ± 10.4 m/day and used areas of 9.4 ± 3.4 ha, while their activity averaged 2.8 ± 0.8 Ϭ m 2 . Males moved 51.4 m/day farther than females, and in general, adult B. cyanea moved 50.3 m/day farther during the avian nesting season than the avian non-nesting season. We refrain from inferring statistical differences with the dBBMM outputs between sexes and seasons within our sample because of the unequal samples and sampling effort during the study period. Only two individuals (one male and one female) were sufficiently radio-tracked across both seasons (the avian nesting and non-nesting seasons), and these two displayed a clear increase in their respective movements, space use and activity during the avian nesting season. This could suggest that movements, space use and activity likely differ between the avian nesting and non-nesting seasons for male and female B. cyanea , however it is only two individuals. All individuals were exclusively nocturnal, moving throughout the night, and often descending from higher diurnal refugia (> 2 m) to forage closer to the ground after sunset. Our openly available data may yield further insight when combined with other major avian nest predator species like the congeneric invasive Brown Tree Snake Boiga irregularis on the island of Guam.