Core-use Areas 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.

Fishing effort dynamics around the Galápagos Marine Reserve as depicted by AIS data.

The waters around the Galápagos Marine Reserve (GMR) are important fishing grounds for authorized artisanal vessels fishing within the reserve as well as for national and foreign industrial fleets operating in the wider Ecuadorian Insular Exclusive Economic Zone (IEEZ). Although it was not originally designed for fisheries management, Automatic Identification System (AIS) data provides useful, open access, near real-time and high-resolution information that allows for increased monitoring, particularly around Marine Protected Areas (MPAs) and in Areas Beyond National Jurisdiction. This study uses AIS data provided by Global Fishing Watch to assess the spatial distribution and seasonal dynamics of fishing effort by vessel flag within the GMR and the IEEZ from 2012 to 2021. Based on kernel density estimation analysis, we determinate the core-use areas (50%) and spatial extent (95%) of fishing activities by fleets (Ecuadorian and foreign), gear types and seasons (warm, from December to May; and cold, from June to November). Our results show that the Ecuadorian fleet recorded the most observed fishing hours in the study area, with 32,829 hours in the IEEZ and 20,816 hours within the GMR. The foreign flags with the most observed fishing hours in the IEEZ were Panama (3,245 hours) and Nicaragua (2,468.5 hours), while in the GMR were the 'Unknown flag' (4,991.4 hours) and Panama (133.7 hours). Vessels fished employing different fishing gears, but the waters of the GMR and IEEZ were mostly targeted by tuna purse-seiners and drifting longlines. The spatial distribution of the fishing effort exhibits marked seasonal variability, likely influenced by seasonal migrations of target species such as tunas (e.g., Thunnus albacares, T. obesus and Katsuwonus pelamis), marlins (e.g., Makaira nigricans) and sharks (e.g., Alopias pelagicus). The collection and use of this type of spatial and seasonal information is an essential step to understand the dynamics of fishing activities in national waters and improve fisheries management, particularly in less studied areas and fisheries.

Distribution patterns of breeding nests in the colonial-breeding Azure-winged Magpie Cyanopica cyanus

ABSTRACT Capsule Distribution patterns of the breeding nests of the Azure-winged Magpie can help to understand spatial and temporal changes in core use areas throughout the breeding range. Aims We investigated the spatial and temporal patterns of nest locations in the breeding colony, to determine the effect of breeding experience and timing on the nest location of Azure-winged Magpies. Methods We collected data on the nest locations of Azure-winged Magpies in a breeding colony and analysed them to identify patterns in nest location. We estimated the nest distribution range through a kernel density analysis, using a geographic information system. Results The size and location of the core use area of the breeding population changed in the following breeding season when the previous year's reproductive success rate was low. We also observed changes in the size and location of the core-use area in relation to the timing of breeding. Conclusion Inter-annual change of the core use area was associated with the timing of breeding and the population's breeding experience.

Green and Hawksbill Sea turtles of Eastern Atlantic: New insights into a globally important rookery in the Gulf of Guinea.

Sea turtles are critical components of marine ecosystems, and their conservation is important for Ocean Governance and Global Planet Health. However, there is limited knowledge of their ecology in the Gulf of Guinea. To fill this knowledge gap, this study presents the first integrative assessment of green and hawksbill turtles in the region, combining nesting surveys over 9 years and telemetry data, to offer insights into these population dynamics, and behaviours, including nesting preferences, morphological and reproductive parameters, diving patterns and inter-nesting core-use areas. Both green and hawksbill turtles are likely making a recovery on São Tomé, potentially driven by sustained conservation efforts. There are preliminary indications of recovery, but we interpret this cautiously. Coupled with satellite tracking, this study estimated that 482 to 736 green turtles and 135 to 217 hawksbills nest on the beaches of São Tomé. Their movements overlap significantly with a proposed Marine Protected Area (MPA), which suggests they may be well placed for conservation if managed appropriately. However, the presence of artisanal fisheries and emerging threats, such as sand mining and unregulated tourism, highlight the urgent need for robust management strategies that align global conservation objectives with local socioeconomic realities. This study significantly enhances our understanding of the ecology and conservation needs of the green and hawksbill turtles in the Gulf of Guinea. The insights gleaned here can contribute to the development of tailored conservation strategies that benefit these populations and the ecosystem services upon which they depend.

Pygmy Blue Whale Home Ranges and Their Overlaps with Indonesian and Australian Marine Protected Areas: Comparison between a-LoCoH and BBMM Methods

Information on the distribution of marine migratory species is lacking, and for a long time, these species have been overlooked in the designation of Marine Protected Areas (MPAs). This study analysed the home range of pygmy blue whales (PBWs) from western Australia to eastern Indonesia to be able to assess the overlap with current MPAs. In this study, data from 11 individual PBWs tagged in the Perth Canyon were used. Two home range methods, adaptive Local Convex Hull (a-LoCoH) and Brownian Bridge Movement Model (BBMM), were performed and compared to identify core use areas and connections between these areas (i.e., migration corridors). By assessing the relative properties and visually inspecting the home ranges, 90% BBMM (home range and migration corridor) and 50% BBMM (core use area) are chosen as the best results, because they cover the connected core-use areas to a large extent. The home ranges that were covered by current MPAs were only 2% in Indonesia and 16% in Australia. Important migration corridors without current protection are in the east Savu Sea, south of Timor Island, and wider Banda Sea. It is noteworthy that comparing methods is relevant to be able to choose the most suitable method for the data used and the goal of this study. The limited overlap between the calculated home ranges and the MPAs of the Indonesian waters articulates the importance of in-depth scientific studies to be able to evaluate, implement and develop marine conservation planning.

Biologically Important Areas II for cetaceans within U.S. and adjacent waters – Hawaiʻi Region

In this assessment we incorporated published and unpublished information to delineate and score Biologically Important Areas (BIAs) for cetaceans in the Hawaiʻi region following standardized criteria. Twenty-six cetacean species have been documented in Hawaiʻi. Eleven odontocete species have distinct small populations resident to one or more island areas: rough-toothed dolphins, pantropical spotted dolphins, common bottlenose dolphins, spinner dolphins, short-finned pilot whales, false killer whales, pygmy killer whales, melon-headed whales, Blainville’s beaked whales, Cuvier’s beaked whales, and dwarf sperm whales. Eight species of mysticetes have been documented, although their occurrence and behavior are poorly understood, with the exception of breeding humpback whales and, more recently, common minke whales. Thirty-five BIAs were delineated or revised from the initial 2015 effort: 33 for small and resident odontocete populations and two for humpback whale reproductive areas. Hierarchical BIAs reflecting core areas of use or population-specific ranges were delineated for nine species. Reproductive watch list areas were designated for common minke whales in the main Hawaiian Islands (MHI) and humpback whales in the Northwestern Hawaiian Islands (NWHI); these areas did not meet the criteria for a BIA due to limited supporting information. All but three BIAs were in the MHI, reflecting the disparities in research effort between this region and the NWHI. Spatial extents of BIA boundaries ranged from 457 km2to 138,001 km2(median = 8,299 km2). Scores (range: 1-3) for Data Support and Boundary Certainty were moderate to high (mean = 2.40 and 2.43, respectively), while Intensity and Importance scores were slightly lower (mean = 1.94 and 1.89, respectively). Many of the Hawaiʻi species have been extensively studied over several decades; accordingly, this region ranks among the highest in terms of Data Support relative to other regions. BIAs presented here describe known ranges of small resident populations, intensities of use, and uncertainties in important areas for cetaceans in Hawaiʻi based on the best available data, and have also revealed knowledge gaps to guide future research efforts.

Combining community science and MaxEnt modeling to estimate Wild Turkey ( Meleagris gallopavo ) winter abundance and distribution

Understanding the distribution and abundance of species is a fundamental aspect of conservation biology. Species distribution models aim to predict distributions based on species observations and ecologically relevant information. To understand the contemporary distribution of Wild Turkeys (<em>Meleagris gallopavo</em>) in Ontario, we curated and collated Wild Turkey flock observations from eBird and iNaturalist submitted during winter 2018. We combined these with environmental predictors to build distribution models using MaxEnt and evaluated model fit using 10-fold cross validation. We also estimated total population size for this species under different modeling scenarios. The potential presence of unknown spatial bias in community science datasets is a complex problem often requiring context-specific statistical solutions. Data cleaning, sometimes referred to as thinning, filtering, or culling, is often proposed to manage this bias. As such, we tested the effect of data cleaning on model outputs and on subsequent analyses. We evaluated all models using area under the curve (AUC). We found building density to be the most important environmental variable followed by winter severity. We validated our habitat suitability estimates using fine-scale GPS data and found that data cleaning had no effect on habitat suitability estimates inside available Wild Turkey habitat or inside core-use areas, except at one site in 2012 (t = -2.2, P = 0.04, df = 14). Use of community collected data offers a cost-efficient and collaborative method to obtain data for species distribution modeling and management. We discuss implications for Wild Turkey management and present potential contemporary distribution maps for this species.

Telemetry-based home range and habitat modelling reveals that the majority of areas important for pygmy blue whales are currently unprotected

Marine migratory species tend to be overlooked in marine spatial planning due to limited knowledge of their habitats and migration pathways, resulting in a disconnect between animal migration ecology and spatial management decision making. The aim of this study was to predict the migratory corridors, suitable habitats and use of marine reserves by pygmy blue whales and overlap with marine traffic. Firstly, based on available telemetry data, we analysed the home ranges, core-use areas and migratory corridors using Brownian Bridge Movement Models. Secondly, we predicted suitable habitat by modelling telemetry data against environmental predictors using Maximum Entropy modelling; and lastly we geometrically overlaid home ranges and suitable habitats with designated migration lanes, marine protected areas and marine traffic. Consistent movement of pygmy blue whales from Western Australia to the Banda and Molucca Seas in Indonesia demonstrated a high level of connectivity between the two regions. There is a discrepancy between the designated migration lanes for large whales in Indonesian marine spatial planning and migration routes suggested by this study. The home range analysis and habitat models revealed that large areas of the migration corridors, core-use, and suitable habitats are currently not protected, particularly along international waters and within the Banda and Molucca Seas. The results can aid marine conservation planning by delineating the important areas and areas with high marine traffic density to optimise migratory species protection.

Livestock Depredation by Jaguars Associated with Dry-Season Core-Use Areas in a Northeastern Mexico Agrolandscape

Predation by jaguars (Panthera onca) on livestock can foster human intolerance and drive human–jaguar conflicts. Understanding distributional patterns that characterize depredation can help guide strategies to ameliorate these interactions, which is important because human conflicts are the main threat to the endangered jaguar in Mexico. We used clusters of satellite telemetry locations to evaluate spatial patterns of jaguars and jaguar predation/scavenging sites of livestock and wild ungulates in the Sierra del Abra-Tanchipa Biosphere Reserve (RBSAT) and surrounding agrolandscape of northeastern Mexico, where livestock composed 66% of the biomass of jaguar diets. Distribution of livestock sites was significantly associated with jaguar core areas (i.e., 50% autocorrelated KDEs) during the dry season, while wild ungulate sites were distributed similarly with respect to core areas of jaguars across both dry and wet seasons. It is unknown whether these results reflect increased chance encounters between jaguars and livestock during the dry season due to the presence of limited permanent water sources concentrating livestock (and natural prey), or due to jaguars actively seeking livestock or livestock carcasses during the dry season.

Ranging Patterns and Site Fidelity of Snubfin Dolphins in Yawuru Nagulagun/Roebuck Bay, Western Australia

For long-lived species such as marine mammals, having sufficient data on ranging patterns and space use in a timescale suitable for population management and conservation can be difficult. Yawuru Nagulagun/Roebuck Bay in the northwest of Western Australia supports one of the largest known populations of Australian snubfin dolphins (Orcaella heinsohni)—a species with a limited distribution, vulnerable conservation status, and high cultural value. Understanding the species’ use of this area will inform management for the long-term conservation of this species. We combined 11 years of data collected from a variety of sources between 2007 and 2020 to assess the ranging patterns and site fidelity of this population. Ranging patterns were estimated using minimum convex polygons (MCPs) and fixed kernel densities (weighted to account for survey effort) to estimate core and representative areas of use for both the population and for individuals. We estimated the population to range over a small area within the bay (103.05 km2). The Mean individual representative area of use (95% Kernel density contour) was estimated as 39.88 km2 (± 32.65 SD) and the Mean individual core area of use (50% Kernel density contour) was estimated as 21.66 km2 (±18.85 SD) with the majority of sightings located in the northern part of the bay less than 10 km from the coastline. Most individuals (56%) showed moderate to high levels of site fidelity (i.e., part-time or long-term residency) when individual re-sight rates were classified using agglomerative hierarchical clustering (AHC). These results emphasize the importance of the area to this vulnerable species, particularly the area within the Port of Broome that has been identified within the population’s core range. The pressures associated with coastal development and exposure to vessel traffic, noise, and humans will need to be considered in ongoing management efforts. Analyzing datasets from multiple studies and across time could be beneficial for threatened species where little is known on their ranging patterns and site fidelity. Combined datasets can provide larger sample sizes over an extended period of time, fill knowledge gaps, highlight data limitations, and identify future research needs to be considered with dedicated studies.

Home Range of a Breeding Male Bald Eagle (Haliaeetus leucocephalus) Tracked via Satellite Telemetry in Kentucky

Haliaeetus leucocephalus (Bald Eagle) is a well-studied species, and information on their nest abundance and population trends is widely available. However, research on the movements and home range of nesting Bald Eagles in the interior US is lacking. In this study, we used a solar-powered Argos platform transmitter terminal (PTT) with global positioning system (GPS) capabilities to monitor the movements of an adult, breeding male Bald Eagle, captured at Ballard Wildlife Management Area, KY, from 29 April 2012 to 23 October 2013. We generated minimum convex polygons (MCP) for comparisons to previous studies and used 95% and 50% fixed kernel density estimators (KDE) to estimate home-range size and core-use areas, respectively, during nesting and non-nesting periods. Estimates of home range and core-use areas were slightly larger during the non-nesting period (MCP = 420.0 km2, 95% KDE = 1.6 km2, 50% KDE = 0.2 km2) when compared to the nesting period (nesting MCP=415.0 km2, 95% KDE =1.3 km2, 50% KDE = 0.01 km2). Our home range and core-use estimates were smaller than previous studies using comparable methods, suggesting that habitat quality at this site may be high.

Habitat selection in the lesser cuckoo, an avian brood parasite breeding on Jeju Island, Korea

BackgroundDetermining patterns of habitat use is key to understanding of animal ecology. Approximately 1% of bird species use brood parasitism for their breeding strategy, in which they exploit other species’ (hosts) parental care by laying eggs in their nests. Brood parasitism may complicate the habitat requirement of brood parasites because they need habitats that support both their host and their own conditions for breeding. Brood parasitism, through changes in reproductive roles of sex or individual, may further diversify habitat use patterns among individuals. However, patterns of habitat use in avian brood parasites have rarely been characterized. In this study, we categorized the habitat preference of a population of brood parasitic lesser cuckoos (Cuculus poliocephalus) breeding on Jeju Island, Korea. By using compositional analyses together with radio-tracking and land cover data, we determined patterns of habitat use and their sexual and diurnal differences.ResultsWe found that the lesser cuckoo had a relatively large home range and its overall habitat composition (the second-order selection) was similar to those of the study area; open areas such as the field and grassland habitats accounted for 80% of the home range. Nonetheless, their habitat, comprised of 2.54 different habitats per hectare, could be characterized as a mosaic. We also found sexual differences in habitat composition and selection in the core-use area of home ranges (third-order selection). In particular, the forest habitat was preferentially utilized by females, while underutilized by males. However, there was no diurnal change in the pattern of habitat use. Both sexes preferred field habitats at the second-order selection. At the third-order selection, males preferred field habitats followed by grasslands and females preferred grasslands followed by forest habitats.ConclusionsWe suggest that the field and grassland habitats represent the two most important areas for the lesser cuckoo on Jeju Island. Nevertheless, this study shows that habitat preference may differ between sexes, likely due to differences in sex roles, sex-based energy demands, and potential sexual conflict.

Foraging and overwintering behavior of loggerhead sea turtles Caretta caretta in the western North Atlantic

Discerning the foraging habitat requirements of wildlife is key to providing for their conservation and management, especially with rare species. Sea turtles are slow-growing, late-maturing species that undertake wide-ranging migrations, making them especially susceptible to changes and disruptions in their environment. To protect and successfully manage these imperiled populations, an understanding of their spatial ecology is required; thus, characterizing critical habitats, identifying high-density areas, and identifying foraging regions is essential. We captured 30 loggerhead sea turtlesCaretta caretta(male and female; juvenile and adult) in the estuarine waters of North Carolina (USA) and tracked them in western North Atlantic neritic (nearshore and offshore) waters. Using a combination of satellite telemetry and spatial modeling techniques, we characterized their movements and identified foraging and overwintering sites. Average core-use areas in the north had greater net primary production (NPP) and were smaller than those in the south, indicating more abundant marine resources in northern foraging regions. In summer, loggerheads migrated to both northern and southern foraging grounds, but most (53%) resided within North Carolina neritic waters. Likewise, the majority of loggerheads (67%) we tracked in winter remained in North Carolina neritic waters, underscoring the importance of this area as year-round foraging habitat, and lending to its consideration as potential critical habitat for both juvenile and adult loggerheads. The change to foraging behavior mode was significantly influenced by day of the year, geographic location, and NPP; however, individual-specific factors influenced switching probabilities relative to other covariates. Data highlighting ‘hotspots’ or densely used areas by foraging sea turtles can thus be used by conservation managers to make informed decisions concerning sea turtle conservation measures.

Modelling habitat use suggests static spatial exclusion zones are a non-optimal management tool for a highly mobile marine mammal

Understanding how animals use the space in which they are distributed is important for guiding management decisions in conservation, especially where human disturbance can be spatially managed. Here we applied distribution modelling to examine common dolphin (Delphinus sp.) habitat use in the Hauraki Gulf (36°S, 175°E), New Zealand. Given the known importance of the area for foraging and nursing, we assessed which variables affect Delphinus occurrence based on generalised additive models (GAMs), and modelled probability of encounter. Behavioural information was included to assess habitat use by feeding and nursing groups and determine whether persistent hotspots for such activities could be identified and meaningfully used as a spatial management tool. Using data collected from dedicated boat surveys during 2010–2012, depth and sea surface temperature (SST) were frequently identified as important variables. Overall, seasonal predictive occurrence maps for the larger population resembled predictive maps of feeding groups more than nursery groups, suggesting prey availability has important implications for the distribution of Delphinus in this region. In this case, static spatial exclusions would not be the best management option as the core areas of use identified for these activities were large and shifted temporally. It appears that at the scale examined, most of the Hauraki Gulf is important for feeding and nursing rather than specific smaller regions being used for these functions. In cases where static management is not the optimal tool, as suggested here for a highly mobile species, a dynamic approach requires more than a boundary line on a map.

Space Use by Prairie Warblers in Regenerating Mixed-oak Forests of Central Pennsylvania

Setophaga discolor (Prairie Warbler) is a Nearctic–Neotropical migratory songbird that is experiencing long-term population declines. A potentially important driver behind these decreases is the loss of shrubland and early successional forest communities in the eastern United States. Central to conservation for species like the Prairie Warbler is an understanding of breeding habitat requirements at the scale of the home range. Despite the Prairie Warbler being identified as a species of continental conservation concern, few studies have explicitly quantified habitat conditions within its home ranges. We used radio telemetry to quantify Prairie Warbler use of space during the breeding season as well as associated vegetation data across 3 study sites in north-central Pennsylvania from May to June 2016. We radio-tracked 11 adult male Prairie Warblers. Using the telemetry locations, we estimated kernel densities and classified minimum convex polygons around kernel densities to define males' home ranges and core-use areas. The average home range (95% kernel) was 6.4 ha, and the average core-use area (50% kernel) was 0.73 ha. Prairie Warbler core-use areas contained more shrubs and lower tree count than peripheral portions of home ranges. To this end, management activities that promote a dense shrub layer across early successional communities should benefit Prairie Warblers. Results from this study serve as baseline data that can be used to help direct future studies at the home-range scale of Prairie Warbler breeding-season ecology.

Habitat and space use of wintering Sprague's Pipits (Anthus spragueii) in northern Mexico

Understanding home range size and habitat preferences is an important component of monitoring species in steep decline. Sprague's Pipit (Anthus spragueii) is a declining grassland specialist with a substantial portion of its population wintering in the highly threatened grasslands of the Chihuahuan Desert. We radio-tagged and tracked 10 wintering pipits between 2014 and 2017 at 3 sites across northern Mexico to generate baseline home range estimates and habitat preferences on their wintering grounds. We found that mean home range and core-use area size with 95% and 50% kernel density estimators were 11.4 ha and 2.4 ha, respectively, almost twice as large as some other grassland specialist passerines. Two birds left the study area and one individual shifted its home range 1.3 km after 20 d of monitoring, indicating that some individuals are flexible in their space use strategies. Within their home ranges, pipits selected grasslands with more bare ground and less “other cover” (litter, duff, animal excrement, and rocks) than what was available on the landscape. We found no relationship at the microhabitat scale between pipits and grass height nor shrub cover and heights, which in previous studies have been shown to influence habitat selection at larger scales. These findings may reflect different habitat use, diet, and predator avoidance strategies than other grassland passerines that select for denser grass cover during winter in the Chihuahuan Desert and highlight the importance of structurally heterogeneous grasslands. For this reason, strategies to manage and conserve Chihuahuan Desert grasslands and its avifauna must consider the diverse habitat and area needs of grassland birds to be effective.

Landscape context matters when American Woodcock select singing grounds: Results from a reciprocal transplant experiment

Abstract The multiscale nature of habitat selection during the breeding season for migratory birds means that core-use areas (e.g., breeding territories) are selected based on their local habitat features, but these may also be influenced in some way by features within a larger-scale landscape. We conducted a reciprocal transplant experiment to test the hypothesis that habitat selection and movements of male American Woodcock (Scolopax minor) in core-use areas during the breeding season depend on the perceived quality of the surrounding landscape. We captured second-year male woodcocks (n = 19) at high- or low-likelihood of use landscapes in Rhode Island, USA, affixed each with a radio transmitter, relocated them to the opposite type of landscape, and then determined if they returned to their original site of capture or remained in the landscape to which they were relocated. Birds captured in high-likelihood landscapes and moved to low-likelihood landscapes generally returned to their original high-likelihood landscape (5/7, 71%), but birds captured in low-likelihood landscapes and moved to high-likelihood landscapes rarely returned to their original low-likelihood landscape (1/12, 8%). These results support the hypothesis that woodcock assess their surroundings relatively rapidly and subsequently make critical settlement decisions based on landscape composition. Given that woodcock choice is predicted by the woodcock-specific resource selection function, these results also provide support for the use of this tool to guide forest management for woodcock.

Resource selection and wintering phenology of White-winged Scoters in southern New England: Implications for offshore wind energy development

AbstractSouthern New England provides key wintering habitat for White-winged Scoters (Melanitta fusca). This area has also pioneered the development of offshore wind energy in North America. The U.S. Bureau of Ocean Energy Management (BOEM) has established 9 Wind Energy Area (WEA) lease blocks along the Atlantic Outer Continental Shelf in areas that may provide important staging and wintering habitat for scoters and other species of sea ducks. Concern over the potential impact of offshore wind energy on sea duck populations has led to efforts to develop models to understand their distribution, habitat use, and site fidelity. We used satellite telemetry to document winter phenology and site fidelity, as well as fine-scale resource selection and habitat use, of 40 White-winged Scoters along the southern New England continental shelf. Scoters spent over half of the annual cycle on the wintering grounds and demonstrated a high degree of interannual site fidelity to composite core-use areas. Sizes of individual 50% core-use home ranges were variable (X¯ = 868 km2; range: 32–4,220 km2) and individual 95% utilization distributions ranged widely (X¯ = 4,388 km2; range: 272–18,235 km2). More than half of all tagged birds occupied 2 or more discrete core-use areas that were up to 400 km apart. Throughout the study area, scoters selected areas with lower salinity, lower sea surface temperature, higher chlorophyll-a concentrations, and higher hard-bottom substrate probability. Resource selection function models classified 18,649 km2 (23%) of the study area as high probability of use, which included or immediately bordered ~420 km2 of proposed WEA lease blocks. Future offshore wind energy developments in the region should avoid key habitats highlighted by this study and carefully consider the environmental characteristics selected by sea ducks when planning and siting future WEAs.

Satellite tracking of hawksbill turtles nesting at Buck Island Reef National Monument, US Virgin Islands: Inter-nesting and foraging period movements and migrations

To conserve imperiled marine species, an understanding of high-density use zones is necessary prior to designing and evaluating management strategies that improve their survival. We satellite-tracked turtles captured after nesting at Buck Island Reef National Monument (BIRNM), St. Croix, US Virgin Islands to determine habitat-use patterns of endangered adult female hawksbills (Eretmochelys imbricata). For 31 turtles captured between 2011 and 2014, switching state-space modeling and home range analyses showed that inter-nesting (IN) core-use areas (i.e., 50% kernel density estimates [KDEs]) were 9.6 to 77.7 km2 in area, occupied for 21 to 85 days, and in shallow water (21 of 26 centroids > −10 m). The IN zones overlapped with areas both within the protected borders of BIRNM, and outside BIRNM (32% of turtle-tracking days outside during IN). Turtles migrated to their foraging grounds between July and October with path lengths ranging from 52 to 3524 km; foraging areas included 14 countries. Core-use foraging areas (50% KDEs) where turtles took up residence were 6.3 to 95.4 km2, occupied for 22 to 490 days, with mean centroid depth − 66 m. Our results show previously unknown habitat-use patterns and highlight concentrated areas of use both within and adjacent to a US protected area during the breeding season. Further, our results clearly demonstrate the need for international conservation to protect hawksbills, as migrating turtles crossed between two and eight different jurisdictions. Our results provide critical spatial and temporal information for managers charged with designing strategies to minimize human impact to and maximize survival for this globally imperiled species.

Satellite tracking a wide-ranging endangered vulture species to target conservation actions in the Middle East and East Africa

Vultures comprise the most endangered avian foraging guild (obligate scavengers) and their loss from ecosystems can trigger trophic cascades, mesopredator release, and human rabies epidemics, indicating their keystone species status. Vultures’ extremely large home ranges, which often cross international borders of countries that have differing laws and capacity for wildlife conservation, makes conserving them challenging. However, satellite-tracking data can be used to identify habitat preferences and critical sites to target conservation actions. We tracked 16 Egyptian Vultures, Neophron percnopterus, in the Middle East and East Africa. We used dynamic Brownian bridge movement models to calculate home ranges and core-use areas, and we analyzed habitat use in a resource selection framework. Combined summer and winter ranges (99% utilization distributions) of all birds covered 209,800 and 274,300 km2, respectively. However, the core-use areas (50% utilization distributions) in the summer and winter ranges, accounted for only 0.4–1.1% of this area (900 and 3100 km2, respectively). These core-use areas are where the home ranges of multiple individuals overlapped and/or where individuals spent a lot of time, such as feeding and roosting sites, and are places where conservation actions could focus. Resource selection models predicted Egyptian Vulture occurrence throughout little-studied parts of the species’ range in the Middle East and East Africa, and revealed strong selection for proximity to highways, power distribution lines, and towns. While providing roosts (e.g. power pylons) and food (e.g. garbage dumps), anthropogenic features may also function as ecological traps by increasing exposure to electrocution and dietary toxins.