Ecuador has both high richness and high endemism of species which are increasingly threatened by anthropic pressures, including roads. However, research evaluating the effects of roads remains scarce, making it difficult to develop mitigation plans. Here we present the first national assessment of wildlife mortality that allow us to 1) identify species and areas where mortality occurs due to collision with vehicles and 2) reveal knowledge gaps. We bring together data from systematic surveys and citizen science efforts in Ecuador to present a dataset with >5000 wildlife roadkill records from 454 species. Systematic surveys were reported by ten studies conducted in five out of the 24 Ecuadorian provinces. Collectively they revealed 282 species with mortality rates ranging from 0.008 to 95.56 ind./km/year. The highest rates were for the yellow warbler Setophaga petechia in Galápagos (95.56 ind./km/year), the cane toad Rhinella marina in Napo (16.91 ind./km/year), and the small ground-finch Geospiza fuliginosa in Galápagos (14.11 ind./km/year). Citizen science and other no systematic monitoring provided 1705 roadkill records representing all the 24 provinces of Ecuador and 299 species. The common opossum Didelphis marsupialis, the Andean white-eared opossum Didelphis pernigra, and the yellow warbler Setophaga petechia were more commonly reported (250, 104, and 81 individuals respectively). Across all sources, we found 15 species listed as Threatened and six as Data Deficient by the IUCN. We suggest stronger research efforts on areas where mortality of endemic or threatened species could be critical for populations, such as in Galápagos. This first assessment of wildlife mortality on Ecuadorian roads represents contributions from several sectors including academia, members of the public, and government underlining the value of wider engagement and collaboration. We hope these findings and the compiled dataset will guide sustainable planning of infrastructure in Ecuador and ultimately, contribute to reduce wildlife mortality on roads.

1. Describing and explaining patterns of individual animal behaviors in situ, and their repeatability over the annual cycle, is an emerging field in ecology owing largely to advances in tagging technology. 2. We describe individual movements of adult Sakhalin taimen Parahucho perryi, an endangered salmonid fish, in the headwaters of a river in northern Japan during the spring spawning season over two years. 3. Migration timing, separated into stages prior to, during, and following the spawning period, was found to be more consistent and repeatable for females than males. 4. We hypothesized that the observed coordinated movement within seasons, and repeatability in migration timing across seasons, could result from 1) individual-specific responsiveness resulting from endogenous, biological traits that are mediated by environmental factors, or 2) social interactions among comigrating individuals. 5. We found that water temperature and water level experienced by fish near the river mouth approximately a week before arrival at the spawning ground explained variability in run timing between years for females but not males. 6. We found no evidence of conspecific attraction or repulsion resulting from social interactions among the spawners and post-spawners. 7. We conclude that individual-specific responsiveness to environmental cues was the likely mechanism underpinning the observed migration timing and movement patterns. 8. Determining the importance of these environmental and social factors not only during spawning but also during non-breeding life-history stages would contribute to a more comprehensive understanding of migratory connectivity in this species.

A document by George Lohay. Click on the document to view its contents.

Animals exhibit unique spatial and temporal behaviors that enhance their survival. Understanding such behaviors is an important step towards effective conservation and management especially of threatened species. In this study, we experimented on whether the Pancake tortoise had the ability to home if translocated and also investigated on site fidelity and territoriality of the species in the natural habitats in Kitui County, Kenya. Behavior of 39 tortoises inhabiting 12 spatially separated rock crevices was studied from July 2020 to June 2022 through radio-tracking, camera trapping and combination of group-level scan sampling and ad libitum sampling. Fourteen of the tortoises were fitted with radio-transmitters and trans-located from their respective home crevices to other crevices away from their respective home crevices and their movement and behavior monitored. With an exception of only two females that adapted well to the new crevices of translocation, all the other tortoises attempted homing, with 46.15% of them tracing their way back to their home crevices with accurate precision and 15.38% also reaching areas believed to be within their home range. The successful homing indisputably gives evidence of strong site fidelity in the species. An analysis of the tortoise crevice occupancy showed that there was no statistically significant difference between numbers of the tortoises initially present in the crevices with the average number present over 162 sampling days (F(1,22) = 0.0699, P >0.05), further supporting strong site fidelity in the species. On the other hand camera trapping events and ad libitum sampling also proved the Pancake tortoises to be territorial with males aggressively defending their territories from other incoming males. Key Words: Animal behavior, chelonian conservation, Ecology, radio-tracking, homing ability.

Evolution of the giraffe neck was originally proposed as an adaptation to foraging at the tops of acacia trees, but this theory has been overshadowed by the “necks for sex” hypothesis that proposed that long necks evolved via sexual selection associated with male neck fighting. The necks for sex hypothesis predicted that males would have longer necks than females and that their necks would continue to grow throughout their lives. Because adult giraffe males are much larger than adult females, male giraffe necks are indeed longer but this is also true for all the core anatomy. We measured and analyzed the relative anatomical proportions of the neck, legs, and body trunk of the Masai giraffe (G.c. tippelskirchi) in captivity in North America and from wild populations in Tanzania. In contradiction to the necks for sex hypothesis, female giraffe have proportionally longer necks compared to their forelegs than males. Moreover, the female body trunk is proportionally longer whereas male forelegs are proportionally longer. We speculate that the proportionally longer female neck is to compensate for female’s overall shorter stature in foraging and their longer trunk is to accommodate fetal growth. Male’s longer forelegs may be an adaptation for mounting females during mating. Mean differences in these major body components define sex phenotypes, but several male and female giraffe display opposite-sex phenotypes with a significantly higher level of discordancy is seen in captive males. We speculate that the sex-differential phenotype is maintained by mate choice selection in the wild, and this selection is relaxed in captivity where mates are arranged by humans.

1. Understanding animals’ selection of microhabitats is important in both ecology and biodiversity conservation. However, there is no generally accepted methodology for the characterisation of microhabitats, especially for vegetation structure. 2. Here we present a method that objectively characterises vegetation structure by using automated processing of images taken of the vegetation against a whiteboard under standardised conditions. We developed an R script for automatic calculation of four vegetation structure variables derived from raster data stored in the images: leaf area (LA), height of closed vegetation (HCV), maximum height of vegetation (MHC), and foliage height diversity (FHD). 3. We demonstrate the applicability of this method by testing the influence of vegetation structure on the occurrence of three viperid snakes in three grassland ecosystems: Vipera graeca in mountain meadows in Albania, V. renardi in loess steppes in Ukraine and V. ursinii in sand grasslands in Hungary. 4. We found that the variables followed normal distribution and there was minimal correlation between those. Generalized linear mixed models revealed that snake occurrence was positively related to HCV in V. graeca, to LA in V. renardi and to LA and MHC in V. ursinii, and negatively to FHD in V. renardi, and to HCV in V. ursinii. 5. Our results demonstrate that biologically meaningful vegetation structure variables can be derived from automated image processing. Our method minimises the risk of subjectivity in measuring vegetation structure, allows upscaling if neighbouring pixels are combined, and is suitable for comparison of or extrapolation across different grasslands, vegetation types or ecosystems.

Designing appropriate management plans requires knowledge of both the dispersal ability and what has shaped the current distribution of the species under consideration. Here we investigated the evolutionary history of the endangered grey reef shark (Carcharhinus amblyrhynchos) across its range by sequencing thousands of RAD-seq loci in 173 individuals in the Indo-Pacific (IP) . We first bring evidence of the occurrence of a range expansion (RE) originating close to the Indo-Australian Archipelago (IAA) where two stepping-stone waves (east and westward) colonized almost the entire IP. Coalescent modeling additionally highlighted a homogenous connectivity (Nm~10 per generation) throughout the range, and an isolation by distance model suggested the absence of barriers to dispersal despite the affinity of C. amblyrhynchos to coral reefs. This coincides with long-distance swims previously recorded, suggesting that the strong genetic structure at the IP scale (FST ~ 0.56 between its ends) is the consequence of its broad current distribution and organization in a large number of demes. Our results strongly suggest that management plans for the grey reef shark should be designed on a range-wide rather than a local scale due to its continuous genetic structure. We further contrasted these results with those obtained previously for the sympatric but strictly lagoon-associated Carcharhinus melanopterus, known for its restricted dispersal ability. C. melanopterus exhibits similar RE dynamic, but is characterized by stronger genetic structure and a non-homogeneous connectivity largely dependent on local coral reefs availability. This sheds new light on shark evolution, emphasizing the roles of IAA as source of biodiversity and of life history traits in shaping the extent of genetic structure and diversity.

In many species, offspring display conspicuous adult-like colouration already early in life, even though they might be very vulnerable to predation at this stage. Yet, the signalling function of adult-like traits in nestlings has been little explored to date. Here, we investigated whether the yellow breast plumage of blue tit (Cyanistes caeruleus) nestlings shows patterns of condition-dependence and hence signals individual quality, as has been described for adult birds. During three consecutive breeding seasons, we therefore explored the association between nestling body mass and three colour components of the yellow breast plumage (i.e., UV chroma, carotenoid chroma and total brightness), considering both within and among nest effects. Carotenoid chroma was not affected by body mass. However, UV chroma and total brightness showed an among-nest effect of body mass, suggesting that they might signal aspects of genetic quality or parental rearing capacity. Interestingly, we also found a within-nest effect of body mass on total brightness, suggesting that this is a good candidate for a condition-dependent signal within the family. Thus, other family members could rely on brightness to adjust their behavioural strategies, such as feeding behaviour in parents. Our study thus reveals that certain colour components of the yellow breast plumage signal different aspects of offspring quality and suggest that they might have a correlated signalling value across life-history stages.

Resource fluctuation is a major driver of animal movement, influencing strategic choices such as residency vs nomadism, or social dynamics. The Arctic tundra is characterized by strong seasonality: resources are abundant during the short summers but scarce in winters. Therefore, expansion of boreal-forest species onto the tundra raises questions on how they cope with winter-resource scarcity. We examined a recent incursion by red foxes (Vulpes vulpes) onto the coastal tundra of western Hudson Bay, an area historically occupied by Arctic foxes (Vulpes lagopus) that lacks access to anthropogenic foods, and compared seasonal shifts in space use of the two species. We used 4 years of telemetry data following 8 red foxes and 11 Arctic foxes to test the hypothesis that the movement strategies of both species are primarily driven by temporal variability of resources. We also predicted that the harsh tundra conditions in winter affect red foxes more than Arctic foxes, which are adapted to this environment. Dispersal was the most frequent winter movement strategy in both fox species, despite its association with high mortality (winter mortality was 9.4 times higher in dispersers than residents). Red foxes consistently dispersed towards the boreal forest, whereas Arctic foxes primarily used sea ice to disperse. Home range size of red and Arctic foxes did not differ in summer, but resident red foxes substantially increased their home range size in winter, whereas home range size of resident Arctic foxes did not change seasonally. As climate changes, abiotic constraints on some species may relax, but associated declines in prey communities may lead to local extirpation of many predators, notably by favoring dispersal during resource scarcity.

Species distribution patterns are essential for the conservation of biodiversity. The aim of this study was to evaluate the influence of multiple ecological hypotheses on the spatial patterns of rodent species richness in China. First, we divided the geographic region of China into 80 × 80 km2 grid cells and mapped the distribution ranges of the 237 rodent species. Rodent taxa were separated into three response variables based on their distribution: (a) all species, (b) non-endemic species, and (c) endemic species. The predictors were divided into four factor sets: (a) energy-water, (b) climatic seasonality, (c) habitat heterogeneity, and (d) human factors, which were used to represent four different ecological hypotheses. We then performed multiple regression analysis (OLS), spatial autoregressive models (SAR), and variation partitioning analyses to determine the effects of predictors on the spatial patterns of rodent species. The Hengduan Mountains and surrounding mountains in southwest China showed the highest species richness and endemism. Habitat heterogeneity is the most important factor explaining the species richness distribution patterns across all species and non-endemic species. Endemic species richness patterns are most susceptible to seasonal changes in climate and least affected by human factors. The effects of energy and water on the three response variables showed consistent levels of importance.

The eastern tree hyrax is thought to be a solitarily living arboreal species of the forests of East Africa. However, in the coast of Kenya, indigenous forests have been almost entirely cleared, and some of the last tree hyrax populations live in limestone rocky formations and caves. Interestingly, they seem to be living in social groups. Here, we describe and document photographically these unique tree hyrax populations. We also describe their acoustical communication and their calling activity in three different habitats. Based on these animals' physical appearance and acoustic analyses of their calls, they represent the species eastern tree hyrax, Dendrohyrax validus. Due to immence pressure from humans, the future of these small and isolated, cave-living tree hyrax populations does not seem bright.

Mammals play a role in environmental engineering. Outside of protected areas, Ethiopia’s mammalian supply is rapidly dwindling, and there is a scarcity of data on mammalian diversity and ecology. As a result, from June 2020 to February 2021, a study was conducted in Arjo Diga Forest to determine the species composition, distribution, relative abundance, and threats of large and medium wild mammals. Using transect lines, survey techniques were used to record mammals from four habitat types, Eighty people participated in a questionnaire survey to identify the current threatening factors. A total of 763 individuals were compiled belonging to 19 mammalian species, 6 orders, and 12 families. Papio Anubis (30.3 %) was the most abundant in the research region, followed by Chlorocebus mitts (22%), while Panthera pardus and Panthera Leo were the least, contributing 0.79 % and 0.39 % of the total observation, respectively. There is, however, a significantly varied among habitats (χ2 = 246.4; DF = 18; P < 0.05). Among observed mammals, (n = 433, 56.75%) individuals were recorded in dry season, while (n = 330, 43.25%) individuals were recorded in wet season and abundance of mammals species not significantly between seasons (χ2 = 12.12; DF = 18; P >0.05). The diversity of species varies depending on the stratified habitat types. The Shannon–Wiener Index values, on the other hand, do not differ much between habitat types. The research area’s species diversity was H′ = 2.296, with the highest Simpson Index of diversity (1-D) being (0.8406). Agricultural land expansion, illegal logging, overgrazing, quarry operations, and illegal hunting are all threats to the species that inhabit the study area. A quick national park is required to rescue these species

Species distribution models (SDMs) are practical tools to assess the habitat suitability of species with numerous applications in environmental management and conservation planning. The manipulation of the input data to deal with their spatial bias is one of the advantageous methods to enhance the performance of SDMs. However, the development of a model parameterization approach covering different SDMs to achieve well-performing models has never been implemented. We integrated input data manipulation and model tuning for four commonly-used SDMs; generalized linear model (GLM), gradient boosted model (GBM), random forest (RF), and maximum entropy (MaxEnt), and compared their predictive performance to model geographically imbalanced biased data of a rare species complex of mountain vipers. Models were tuned up based on a range of model-specific parameters considering two background selection methods; random and background weighting schemes. The performance of the fine-tuned models was assessed based on a recently identified localities of the species. The results indicated that although the fine-tuned version of all models shows great performance in predicting training data (AUC > 0.9 and TSS > 0.5), they produce different results in classifying out-of-bag data. The GBM and RF with higher sensitivity of training data showed more different performances. The GLM, despite having high predictive performance for test data, showed lower specificity. It was only the MaxEnt model that showed high predictive performance and comparable results for identifying test data in both random and background weighting procedures. Our results highlight that while GBM and RF are prone to overfitting training data and GLM over-predict non-sampled areas MaxEnt is capable of producing results that are both predictable (extrapolative) and complex (interpolative). We discuss the assumptions of each model and conclude that MaxEnt could be considered as a practical method to cope with imbalanced-biased data in species distribution modeling approaches.

High-through chromosome conformation capture (Hi-C) technique is widely used to study the functional roles of the three-dimensional (3D) genome architecture of genomes. However, knowledge of 3D genome structure and its dynamic during extreme environments adaption remain poor. Here we characterized 3D genome architectures with Hi-C technique for chicken liver cells. By comparing Lindian chicken (LDC) liver cells with Wenchang chicken (WCC) liver cells, we discovered that environmental adaption contributed to the switching of A/B compartments, the reorganization of topologically associated domains (TADs) and TAD boundaries in both liver cells. Besides, analysis of the switching of A/B compartments combined with liver transcriptome revealed the corresponding changes of gene expression were strongly associated with extreme environment adaption-related pathways, including Tight junction, Notch signaling pathway, Vascular smooth muscle contraction, RIG-I-like receptor signaling pathway and Glycosphingolipid biosynthesis pathways. This study advanced our understanding of evolutionary role of chicken 3D genome architecture and their significance in genome activity and transcriptional regulation.

1. Animal abundance estimation is increasingly based on drone or aerial survey photography. Manual post-processing has been used extensively, however volumes of such data are increasing, necessitating some level of automation, either for complete counting, or as a labour-saving tool. Any automated processing can be challenging when using the tools on species that nest in close formation such as Pygoscelid penguins. 2. We present here an adaptation of state-of-the-art crowd-counting methodologies for counting of penguins from aerial photography. 3. The crowd-counting model performed significantly better in terms of model performance and computational efficiency than standard Faster RCNN deep-learning approaches and gave an error rate of only 0.8 percent. 4. Crowd-counting techniques as demonstrated here have the ability to vastly improve our ability to count animals in tight aggregations, which will demonstrably improve monitoring efforts from aerial imagery.

This study assessed species diversity, abundance, and habitat association of medium and large-sized mammals in the Gelama block of Arsi Mountains National Park, Southeast Ethiopia. The study covered two seasons extending between February and August 2020. Based on the vegetation cover and topographic variation, the study area was stratified into four habitat types. A total of 74 transect lines were systematically established, 14 for Afroalpine, 26 for Ericaceous, 18 for Natural forest, and 16 for Mixed plantation. The survey for mammals was done by walking on foot along each transect. A total of 25 medium and large-sized mammals were recorded, including globally threatened and endemic mammals like Canis simensis and Tragelaphus buxtoni. Results showed a significant difference in the abundance of medium and large-sized mammals among the four habitat types: dry (χ2 =126.256, df =3, P=0.000) and wet (χ2 =74.822, df =3, P=0.000) seasons. During the dry season, the highest and lowest species diversity was recorded in the natural forest (H’=2.488) and mixed plantations (H’=2.154). During the wet season, ericaceous vegetation sheltered the highest diversity of mammalian species (H’=2.224), while mixed plantation forests inhabited the lowest species diversity (H’=1.788). The presence of food, cover, and water availability were the main factors for the differences in species diversity and abundance across the habitats. Phacochoerus africanus was the most abundant species during the dry (16.89%) and wet (18.81%) seasons. However, Felis caracal (0.14 during dry) and Panthera pardus (0.36 during wet season) were the least abundant species recorded. Occurrence of abundant species was associated with their feeding habits and physiological adaptation. Although the study area is home to different species of mammals, including endangered and endemics, livestock grazing and human encroachments are evident, putting strain on flora and fauna. Hence, conservation measures should be taken to ensure long-term conservation of the area.

Abstract: Throughout evolutionary history, animals are finely tuned to adjust their behaviors corresponding to environmental variations. Behavioral flexibility represents an important component of a species’ adaptive capacity in the face of rapid anthropogenetic environmental change, and knowledge of animal behaviours is increasingly recognized in conservation biology. In aquatic ecosystem, variation of water depth is a key factor affecting the availability of food, thus the foraging behaviours of many waterbirds, especially piscivores. In this study, we compared the foraging behaviours of Scaly-sided Merganser (Mergus squamatus), an endangered migratory diving duck endemic to east Asia, in habitats with different water depth, using video camera records obtained from the known wintering sites during three winters from 2018-2020. Further, the energy expenditure of foraging behavior profile and energy intake based on fish sizes were calculated to study the foraging energetics. In total, 200 effective video footages that contained 1,086 minutes with 17,995 behaviours and 163 events of catching fish were recorded. Results showed that 1) time length for fishing (including eye-submerging, head-dipping, diving and food handling) of Mergus squamatus in shallow waters was significantly more than in deep waters; 2) Mergus squamatus spent significantly more time for preparing (including vigilance, preening and swimming) in deep waters than in shallow waters; 3) the mean catch rate was 0.28 fish/minute in shallow waters, which is significantly higher than the value of 0.13 fish/minute in deep waters; 4) despite the distinct foraging behaviour profiles and energy intakes, Mergus squamatus showed similar energetics in shallow and deep waters. We concluded that Mergus squamatus is a good example of behavioural flexibility that aligns with expectations of optimum foraging theory, in that it behaves in accordance to resource availability in different environments, resulting in high foraging efficiency. The behavioural flexibility can be related to its evolution history.

Saltwater- and freshwater environments have opposing physiological challenges, yet, there are fish species that are able to enter both habitats during short time-spans, and as individuals they must therefore adjust quickly to osmoregulatory contrasts. In this study, we conducted an experiment to test for plastic responses to abrupt sainity changes in two poplulations of threespine stickleback, Gasterosteus aculeatus, representing two ecotypes (freshwater and ancestral saltwater). We exposed both ecotypes to abrupt native (control treatment) and non-native salinities (0 and 30‰) and sampled gill-tissue for transcriptomic analyses after six hours exposure. To investigate genomic responses to salinity, we analysed four different comparisons; one for each ecotype (in their control and exposure salinity; 1 and 2), one between ecotypes in their control salinity (3), and the fourth comparison included all transcripts identified in (3) that did not show any expressional changes within ecotype in either the control or the exposed salinity (4). Abrupt salinity transfer affected the expression of 10 and 1530 transcripts for the saltwater and freshwater ecotype, respectively, and 1314 were differentially expressed between the controls, including 502 that were not affected by salinity within ecotype (fixed expression). In total, these results indicate that factors other than genomic expressional plasticity are important for osmoregulation in stickleback, due to the need for opposite physiological pathways to survive the abrupt change in salinity.

As demand for food increases, agricultural production is poised to increase dramatically. Pesticides are commonly used to maintain high crop yield, though they have several drawbacks, including reduced efficacy over time and harmful effects to human and ecosystem health. Bats are highly effective predators of crop pests and have great potential to reduce crop damage resulting from insects. However, few studies have investigated how pest control by bats might change over large expanses of continuous row crop agriculture, which is common in the Midwest. Agricultural landscapes offer few roosting opportunities and could be difficult for bats to traverse, which might affect the degree of ecosystem services provided by bats. We hypothesized that with increasing distance into uninterrupted row crop agriculture 1) bat activity would decrease and 2) bat species richness would decrease, but that these effects would be buffered when insect pest abundance is high. We deployed 50 acoustic bat detectors over 10 transects in east-central Illinois from July to September 2021. In each transect, we placed detectors on crop field edges at increasing distance from a large riparian corridor assumed to be frequented by bats. Bat activity was high across the landscape but declined by 56% from the forest edge to 4000m into row crop agriculture, while bat diversity decreased by 34%. Pest abundance seemed to decrease overall bat activity but had no effect on bat diversity. These results indicate that bats, although able to have a large effect on crop pest reduction, might not be as efficient in suppressing crop pests in vast uninterrupted agricultural landscapes which offer scant roost availability. Our work will inform recommendations to landowners and private lands managers on ways to increase bat access to roosts and forest cover near agricultural areas, thereby enhancing the potential for bats to provide pest control services.

Many populations of long-distance migrant shorebirds are declining rapidly. Since the 1970s, the Lesser Yellowlegs (Tringa flavipes) has experienced a pronounced reduction in abundance of ~63%. The potential causes of the species’ decline are complex and interrelated yet understanding the timing of migration and seasonal routes used by this species will aid in directing conservation planning to address potential threats. During 2018–2021, we tracked 118 adult Lesser Yellowlegs using GPS satellite tags deployed on birds from five breeding and two migratory stopover locations spanning the boreal forest of North America from Alaska to eastern Canada. Our objectives were to quantify migratory connectivity and identify key stopover and non-breeding locations. Individuals tagged in Alaska and central Canada followed similar southbound migratory routes through the Prairie Pothole Region of North America, whereas birds tagged in eastern Canada completed multi-day transoceanic flights covering distances of >4,000 km across the Atlantic between North and South America. Upon reaching their non-breeding locations, Lesser Yellowlegs populations overlapped, resulting in weak migratory connectivity. Lastly, freshwater and agricultural habitats of the Prairie Pothole region supported the highest proportion of Lesser Yellowlegs during southbound migration. Our findings suggest that while Lesser Yellowlegs travel long distances and traverse numerous political boundaries each year, the breeding population from which an individual originates likely has the greatest influence on which threats birds experience during migration. Further, the species’ dependence on wetlands in agricultural landscapes during migration may make them vulnerable to threats related to agricultural practices, such as pesticide exposure.

Birds of prey frequently feature in reintroductions and the hacking technique is typically used. Hacking involves removing large nestlings from donor populations, transferring them to captivity, feeding them ad libitum. Potentially, via the hacking method, stress of captivity and disruption of parental feeding may be detrimental. Alternatively, provision of ad libitum food may be advantageous. Although hacking has underpinned reintroduction project successes there has been no research on how the method may affect the health and nutritional status of translocated birds during captivity. We compared blood chemistry data from 55 young White-tailed Eagles, translocated from Norway as part of the species’ reintroduction to Scotland, from sampling soon after arriving in captivity and again (≈ 42 d later) before their release. Numerous significant differences between first and second samples were found, but no significant interactions showed that sexes responded similarly to captivity. According to hematological and biochemical metrics, individuals showed several changes during captivity, including in red blood cell parameters, plasma proteins and white cellular parameters related to the immune system, that indicated improved health status. Captivity with ad libitum food was associated with decreased urea and uric acid values: high values can indicate nutritional stress. Urea values became more normally distributed before release, indicating that ad libitum food had reduced nutritional differences between early nestlings in the season and later ones. Despite plentiful food, both sexes lost body mass before release, suggesting an inherent physiological mechanism to improve flight performance in fledglings. We conclude that hacking improved the health and nutritional status of released eagles which is likely to enable birds to cope with greater costs of exploratory behavior which they may require in reintroduction projects. In this context, we note the absence of survival differences between hacked and wild raptors in previous research.

An individual’s size in early stages of life may be an important source of individual variation in lifetime reproductive performance, as size effects on ontogenetic development can have cascading physiological and behavioral consequences throughout life. Here, we explored how natal size influences subsequent reproductive performance in grey seals (Halichoerus grypus) using repeated encounter and reproductive data on a marked sample of 363 females that were measured for length at ~4 weeks of age and eventually recruited to the Sable Island breeding colony. Two reproductive traits were considered: provisioning performance (mass of weaned offspring), modeled using linear mixed effects models; and reproductive frequency (rate at which a female returns to breed), modeled using mixed-effects multistate mark-recapture models. Mothers with the longest natal lengths produced pups 8 kg heavier and were 20% more likely to breed in a given year than mothers with the shortest lengths. Correlation in body lengths between natal and adult life stages, however, is weak: longer pups do not grow to be longer than average adults. Thus covariation between natal length and future reproductive performance appears to be a carry-over effect, where the size advantages afforded in early juvenile stages may allow enhanced long-term performance in adulthood.

1. Passive Acoustic Monitoring is emerging as a solution for monitoring species and environmental change over large spatial and temporal scales. However, drawing rigorous conclusions based on acoustic recordings is challenging, as there is no consensus over which approaches and indices are best suited for characterizing marine acoustic environments. 2. We present an alternative to the use of ecoacoustic indices and describe the application of multiple machine learning techniques to the analysis of a large PAM dataset. We combine pre-trained acoustic classification models, dimensionality reduction, and random forest algorithms to demonstrate how machine-learned acoustic features capture different aspects of the marine environment. We processed two PAM databases and conducted 13 trials showing how acoustic features can be used to: i) discriminate between the vocalizations of marine mammals, beginning with high-level taxonomic groups, and extending to detecting differences between conspecifics belonging to distinct populations; ii) discriminating amongst different marine environments; and iii) detecting and monitoring anthropogenic and biological sound sources. 3. Acoustic features and their UMAP projections exhibited good performance in the classification of marine mammal vocalizations. Most of the taxonomic levels investigated here could be classified using the UMAP projections, apart from species that were underrepresented. Both anthropogenic (ships and airguns) and biological (humpback whales) sound sources could also be identified in field recordings. 4. We argue that acoustic feature extraction, visualization, and analysis allows the retention of most of the environmental information contained in PAM recordings, overcoming the limitations encountered when using ecoacoustics indices. Acoustic features are universal, permitting comparisons of results collected from multiple environments. Our approach can be used to simultaneously investigate the macro and micro characteristics of marine soundscapes, with a more objective method and with far less human effort.

Wolves (Canis lupus) can exert top-down pressure and shape ecological communities through selective predation of ungulates and beavers (Castor Canadensis). Considering their ability to shape communities through predation, understanding wolf foraging decisions is critical to predicting their ecosystem level effects. Specifically, if wolves are optimal foragers, consumers that optimize tradeoffs between cost and benefits of prey acquisition, changes in these factors may lead to prey switching or negative-density dependent selection with potential consequences for community stability. For wolves, factors affecting cost and benefits include prey vulnerability, risk, reward, and availability which can vary temporally. We described wolf diet in by frequency of occurrence and percent biomass and characterized diet in relation to optimal foraging using prey remains found in wolf scats on Isle Royale National Park, Michigan, USA during May–October 2019–2020. We used logistic regression to estimate prey consumption over time. We predicted prey with temporal variation in cost (vulnerability and/or availability) such as adult and calf moose (Alces alces) and beaver to vary in wolves’ diet. We analyzed 206 scats and identified 62% of remains as beaver, 26% as and moose, and 12% as other (birds, smaller mammals, and wolves). Adult moose were more likely to occur in wolf scat in May, when moose are in poor condition following winter. Similarly, the occurrence of moose calves peaked June–mid July following parturition but before their vulnerability declined as they matured. In contrast, beaver occurrence in wolf scat did not change over time, possibly reflecting the importance of low handling cost prey items for recently introduced lone or paired wolves. Our results demonstrate that wolf diet is plastic and responsive to temporal changes in prey acquisition cost as predicted by optimal foraging theory. Temporal fluctuation in diet may influence wolves’ ecological role if prey respond to increased predation risk by altering their foraging or breeding behavior.