Movement Ecology

Forage fishes play a vital role to marine ecosystems by linking lower trophic levels to top predators and serving as key economic and food resources for commercial and subsistence fisheries. Despite their significance, knowledge of forage fish movement throughout their life cycle in Canadian waters remains limited, hindering effective management and conservation. This study synthesises current knowledge of the movement ecology of seven of Canada’s key forage fish species: capelin (Mallotus villosus), Atlantic mackerel (Scomber scombrus), Atlantic herring (Clupea harengus), Pacific herring (Clupea pallasii), Arctic cod (Boreogadus saida), eulachon (Thaleichthys pacificus), and sand lances (Ammodytes spp). We assess the methodologies used to study their movements, spanning from traditional capture-mark-recapture techniques and fisheries-dependent or independent surveys to advanced approaches such as acoustic telemetry and natural chemical tracers. Significant knowledge gaps persist in remote locations where research is limited, as well as for non-commercially exploited species and specific life phases such as overwintering, which remain poorly understood across all species. To address these knowledge gaps, we underscore the value of combining conventional and modern methodologies. Additionally, we advocate for incorporating indigenous knowledge, such as the holistic knowledge of Inuit (Inuit Qaujimajatuqangit), and community-based observations to enrich insights. Implementing these recommendations and advancing our knowledge of forage fish migration is crucial for predicting the impacts of environmental change on fish movement and for ensuring their sustainability, as well as the ecosystems and fisheries they support.

St. Anns Bank, situated offshore of Cape Breton, Nova Scotia, was designated a Marine Protected Area (MPA) under the Oceans Act in 2017 to conserve and protect benthic, demersal, and pelagic habitats, in addition to the high biodiversity and productivity in the area. Monitoring programs have been ongoing for St. Anns Bank MPA (SAB MPA) both before and after its establishment. This report summarizes the acoustic telemetry data collected in SAB MPA from 2015 to 2023. To date the gates of receivers in the MPA (26 to 46 receivers per year) have detected 330 tagged animals and 13 species from 33 distinct research projects, including Canadian DFO and international projects. In addition, 174 separate animals and seven species have been detected that were tagged in the MPA by the SABMPA tagging program. The most frequently detected species tagged by other projects were Atlantic Salmon, Bluefin Tuna, Blue Shark, Atlantic Cod, and White Shark. Atlantic Cod were detected migrating seasonally to spend winter in the Gulf of St. Lawrence and much of the rest of the year in SABMPA. Receivers deployed near shallow banks (e.g., Scatarie Bank) had the highest residency for species that spent the majority of the year in SAB MPA (Atlantic Cod, Atlantic Halibut, Atlantic Striped Wolffish) and species generally only present during summer/fall months (e.g., White Shark, Bluefin Tuna). Thirty-nine individuals and six species have been detected returning to SAB MPA at least once in a sequential year since 2015, demonstrating the value of a long-term monitoring platform for detecting possible changes in these species’ behaviour. Detections of these animals informs on the importance of the MPA as a seasonal migratory corridor with common seasonal latitudinal pathways identified in the MPA and connectivity to the Gulf of St. Lawrence, Nova Scotian south shore, Newfoundland coast, the USA eastern seaboard, and eleven different freshwater systems throughout Canada and the USA. This large dataset provides direct evidence of species occurrence in the MPA and informs on spatial and temporal variation in the timing of migration and residency. We explore several potential drivers of variation in detections and residency, including MPA Zone, bottom temperature, habitat type, and depth, and discuss the implications for conservation objectives and indicators for long-term monitoring.

This article provides an introductory review of semiotic processes in ecosystems, inhabited by humans and other organisms, making emphasis on the role of semiosis in organization of ecosystems. The field that studies human views on nature has been called ecosemiotics, while the study of semiotic processes in an ecosystem can be called the semiotics of ecosystem or ecosystem semiotics or semiotic ecology. Since semiotic and physical processes work together, a more general approach is also reasonable, which would take both semiotic and physical aspects into account; this is ecosystemic semiotics.
Topics: Ecosystem as Such: Its Physical and Semiotic Processes; Umwelten, Meaning-Making, and Organisms ’ Choices; Semiotic Fitting, Habits, and Semiotic Niches; Sympoiesis, Consortia, and Holobionts; Movement Ecology and Semiotic Niche; Species and Intraspecific Communicative Congregations; Succession and Balance: Semiorhesis; Seminatural Ecosystems.

Background There are now a wide array of eld and laboratory techniques available for gaining insight into the movement and behaviour of sharks. Although acoustic telemetry may lack the ne-scale resolution of some satellite technologies, the low cost and longer battery life make it a powerful tool for investigating elasmobranch behaviour. Here, we develop a novel approach to analysing acoustic telemetry data, using detection gaps to infer movement patterns to and from monitored reef habitats, to investigate spatial and temporal segregation between two sympatric shark species in a large remote MPA. Methods A total of 102 grey reef sharks (Carcharhinus amblyrhynchos) and 76 silvertip sharks (Carcharhinus albimarginatus) were tted with long-term acoustic transmitters and tracked inside a large acoustic array of reef-based receivers in the British Indian Ocean Territory MPA, between 2014 and 2018. From the resulting dataset (768,081 detections), movements between receivers and recursive loops to the same receiver were identi ed. Using the durations of inter-receiver movements (i.e. detection gaps), individual behaviours were classi ed into 'restricted' or potential wider 'out of range' movements. Drivers of these movements were identi ed using network analysis, GLMMs and multi-model inference starting from an a priori set of explanatory variables. Results In general, silvertip sharks were more likely to undertake 'out of range' movements than grey reef sharks. 'Out of range' movements were more common at night compared to during the day, and during the wet season compared to the dry season. In addition, the difference in 'out of range' movements between the two species increased at night. These results suggest spatial and temporal segregation of movements between the two species. Conclusions We present a novel analysis of detection gaps from acoustic telemetry data to infer differential movement patterns and describe how species organise in space and time. Furthermore, this approach shows that acoustic telemetry gap analysis can be used for comparative studies, or combined, with other research techniques to better understand the functional role of sharks in reef ecosystems, moving towards more informed strategies for the conservation and management of the marine environment.

Background There are now a wide array of field and laboratory techniques available for gaining insight into the movement and behaviour of sharks. Although acoustic telemetry may lack the fine-scale resolution of satellite telemetry, the low cost and longer battery life make it a powerful tool for investigating elasmobranch behaviour. Here, in the absence of satellite tracking data, we develop a novel approach to analysing acoustic telemetry data, using detection gaps to infer movement patterns to and from monitored reef habitats, to investigate spatial and temporal segregation between two sympatric shark species in a large remote MPA. Methods A total of 102 grey reef and 76 silvertip sharks were fitted with long-term acoustic transmitters and tracked inside a large acoustic array of reef-based receivers in the British Indian Ocean Territory MPA, between 2014 and 2018. From the resulting dataset (768,081 movements), movements between receivers and recursive loops to the same receiver...

This two-week undergraduate module introduces students to the principles of avian flight mechanics and the behavioral ecology of birds through an integrated combination of lectures, laboratory exercises, and field-based observations. Students examine how morphological and physiological adaptations-such as wing shape, muscle structure, and body mass-affect flight performance, energetic efficiency, and ecological behaviors including foraging, habitat use, and anti-predator strategies. Using locally occurring bird species as focal case studies, students collect quantitative data on morphology, flight-related traits, and behavior, and analyze these data to test biologically meaningful hypotheses. The module emphasizes scientific process skills, including systematic observation, experimental design, statistical analysis, and oral and written communication of results. Designed to be adaptable across geographic regions and habitat types, this module provides instructors with a flexible framework that can be tailored to local avian communities while reinforcing broadly applicable concepts in biomechanics, ecology, and evolutionary biology.

Background: Flying foxes (Chiroptera: Pteropodidae) are large bats that often roost in the sun, hence solar-powered GPS/GSM devices can track their movements over extended periods. The endemic Mauritian flying fox (Pteropus niger) has recently been subjected to large-scale culling because of perceived damage to commercial fruit, and a consequent reduction in numbers of > 50% since 2015 resulted in its IUCN Red List Status being up-listed to Endangered. Determining its movements will be important for management and conservation, for understanding potential responses to environmental change, and for understanding population admixture. Methods: Twelve bats were tagged with solar-powered GPS/GSM devices in 2014-2016. Tags remained active for up to almost a year (maximum 359 days: average 139 days (males) and 93 days (females)), providing some of the longest-term data on the movement ecology of bats yet obtained. Eight bats were probably hunted illegally, highlighting the scale of unauthorised persecution. Results: Males travelled on average 9 km each night, females 6 km. The nightly distance covered by adults of both sexes was higher in winter than in summer, though the opposite pattern occurred for immature males. These differences are probably related to seasonal changes in fruit availability (adults) and to dispersal by immature males. The maximum distance covered during one night was > 92 km. Home ranges of males averaged 74,633 ha, females 31,072 ha. Core foraging areas averaged 2222 ha for males, 1364 ha for females. Fifty roosts were identified, mainly in forest fragments. As the bats disperse seeds of native plants that form forest canopies, conservation of the bats will potentially maintain and enhance native forest cover, in turn providing roosting sites for the bats. Conclusions: Solar-powered GSM tagging provides unprecedented potential for understanding the movement ecology of flying foxes. Mauritian flying foxes often move between the few remnant native forest fragments, which remain important for their conservation, and have potentially important roles in seed dispersal. Their nomadic movement fits with their panmictic genetic structure. Although their ability for long distance movements, sometimes over short timescales, permits rapid responses to local threats and environmental change, being restricted to Mauritius renders the bats extremely vulnerable to intense culling.

The role of indigenous grazing management practices in sustainable natural resource use has been widely identified and recognised in the literature. However, the grazing management practices of Nama pastoralists in the semi-arid regions in Namaqualand in South Africa have not been adequately studied in terms of GPS-based seasonal grazing distribution. This study aimed to assess the seasonal livestock grazing distributional patterns across three communal rangelands in Namaqualand using GPS collars. The objectives were to: (1) generate grazing distributional maps to identify patterns of seasonal rangeland use, (2) compare area covered at different grazing intensities of livestock between seasons, (3) delineate different grazing zones at different times of day, and (4) contrast seasonal differences within these grazing zones regarding grazing activity. CatLog GPS collars were mounted on livestock and T-LoCoH R package and Google Earth were used to generate grazing distribution maps showing areas most and least frequently used by livestock and daily movement patterns. The results showed that Namaqualand herds grazed only a small proportion (21.1%) of their mean home range (809.6 ± 76.2 ha) at high and moderate grazing intensities, regardless of season, corresponding to areas of 48.1 ± 13.5 ha and 287.7 ± 41.60 ha, respectively. In the wet season, herds used a 16.8% larger area than in the dry season. The area associated with high grazing densities was significantly smaller than areas grazed at lower grazing pressure. No significant differences in mean area associated with seasonal variation within each level of grazing suggests herders are not seasonally altering areas associated with high grazing intensity, which are sometimes associated with permanent water sources. It is also likely that herders are concerned about ensuring their livestock have sustained access to optimal forage sources by avoiding other flocks using the same areas. Grazing activity is indirectly proportional to grazing speed. Grazing activity is lower in the herded zones (the morning-excitement/appetite moderation zone and the early afternoon-target zone, mean speed = 0.955 ± 0.006 km h-1) than when in an unherded zone (late afternoon-late afternoon meal, mean speed = 0.852 ± 0.010 km h-1). Mean distance travelled daily by herds in the herded zones was greatest (4.773 ± 0.029 km). In the wet season (7.365 ± 0.055 km) and a greater area was covered daily (10.6 ± 1.2 ha) as resources become more abundant relative to the dry season. This suggests that indigenous herding practices in Namaqualand require ecologically aware decision-making processes associated with effective resource use. Contemporary grazing management policies should be more inclusive of indigenous management as aspects of holistic grazing management have been embedded in these practices for centuries.

The critically endangered African forest elephant (Loxodonta cyclotis) plays a vital role in maintaining the structure and composition of Afrotropical forests, but basic information is lacking regarding the drivers of elephant movement and behavior at landscape scales. We use GPS location data from 96 individuals throughout Gabon to determine how five movement behaviors vary at different scales, how they are influenced by anthropogenic and environmental covariates, and to assess evidence for behavioral syndromes-elephants which share suites of similar movement traits. Elephants show some evidence of behavioral syndromes along an 'idler' to 'explorer' axis-individuals that move more have larger home ranges and engage in more 'exploratory' movements. However, within these groups, forest elephants express remarkable inter-individual variation in movement behaviours. This variation highlights that no two elephants are the same and creates challenges for practitioners aiming to design conservation initiatives. Movement is a fundamental characteristic of animal biology, and the movement decisions animals make have profound implications across individual, population and ecosystem-levels. At the individual-level, movement behaviour influences fitness through the ability to find resources, survive and reproduce . At the populationlevel, movement characteristics can influence interactions with competitors, predators and disease . At the ecosystem-level, animal movement can determine the location of dispersed pollen, seeds and nutrients and the spatial intensity of herbivory, predation and disturbance 5 . Conserving species and functioning ecosystems, therefore, depends on understanding how and why animals move and the consequences of such decisions. There is increasing recognition of the importance in quantifying the role of, and variation associated with, individual movement patterns. This change is assisted by the increasing availability of high quality animal tracking data and the associated development of powerful analytical frameworks which can quantify movement behavior at sufficiently fine temporal scales 1 . Where explored, individual-level variation in movement behaviors is often a typical feature of movement data sets and can translate into individual variation in resource acquisition, body mass, reproductive output, and survival 9 . Individual variation can facilitate coexistence of multiple individuals through reductions in competition for resources and has profound implications for management of humanwildlife conflict through identification of problem individuals 12 . Characterizing multiple movement behaviors at the individual-level can also reveal behavioral syndromes-correlated suites of behaviors that can constrain or enhance how individuals and populations respond to anthropogenic disturbance or novel environments 13 . As GPS tracking typically involves following multiple individuals across ecologically meaningful time periods, it is perfectly suited for assessments of behavioral syndromes. To date, studies with a sufficient number of tracked animals over a large enough spatial area to assess heterogeneity in movements with environmental and anthropogenic factors are rare, even in large mammals 13 , but see . Ultimately, identification of factors governing animal movement and behavioral syndromes could lead to targeted regional-or syndrome-specific management recommendations, resulting in more effective conservation and resolution of human-wildlife conflict. The African forest elephant (Loxodonta cyclotis) plays a pivotal ecological role in seed dispersal, nutrient recycling and herbivory, ultimately influencing the structure and functioning of Afro-tropical forests 15 . However, research into forest elephant movement behavior has been limited to small sample sizes and small temporal and spatial scales, as direct observations of forest elephants are largely restricted to non-forest, open habitats

Species translocation is a popular approach in contemporary ecological restoration and rewilding. Improving the efficacy of conservation translocation programmes requires a combination of robust data from comparable populations, population viability modelling and post-release monitoring. Biotelemetry is becoming an ever more accessible means to collect some of the high-resolution information on the ecology and behaviour of founding populations that such evaluations require. Here, we review 81 published case studies to consider how this capability could increase the success of avian translocations. We found that 67 translocations favoured traditional radio telemetry, with surveillance focussing mostly on immediate post-release dispersal, survival and breeding attempts. Just 28 projects tracked founder individuals for longer than 1 year and no studies referenced pre-release sampling or planning using biotelemetry. While our review shows that tracking devices have been deployed extensi...

The residence time is the amount of time spent within a predefined circle surrounding each point along the movement path of an animal, reflecting its response to resource availability/quality. Two main residence time-based methods exist in the literature: (1) The variance of residence times along the path plotted against the radius of the circle was suggested to indicate the scale at which the animal perceives its resources; and (2) segments of the path with homogeneous residence times were suggested to indicate distinct behavioral modes, at a certain scale. Here, we modify and integrate these two methods to one framework with two steps of analysis: (1) identifying several distinct, nested scales of area-restricted search (ARS), providing an indication of how animals view complex resource landscapes, and also the resolutions at which the analysis should proceed; and (2) identifying places which the animal revisits multiple times and performs ARS; for these, we extract two scale-dependent statistical measures-the mean visit duration and the number of revisits in each place. The association between these measures is suggested as a signature of how animals utilize different habitats or resource types. The framework is validated through computer simulations combining different movement strategies and resource maps. We suggest that the framework provides information that is especially relevant when interpreting movement data in light of optimal behavior models, and which would have remained uncovered by either coarser or finer analyses. animal movement, movement path analysis, first passage time, foraging behavior.

The residence time is the amount of time spent within a predefined circle surrounding each point along the movement path of an animal, reflecting its response to resource availability/quality. Two main residence time-based methods exist in the literature: (1) The variance of residence times along the path plotted against the radius of the circle was suggested to indicate the scale at which the animal perceives its resources; and (2) segments of the path with homogeneous residence times were suggested to indicate distinct behavioral modes, at a certain scale. Here, we modify and integrate these two methods to one framework with two steps of analysis: (1) identifying several distinct, nested scales of area-restricted search (ARS), providing an indication of how animals view complex resource landscapes, and also the resolutions at which the analysis should proceed; and (2) identifying places which the animal revisits multiple times and performs ARS; for these, we extract two scale-dependent statistical measures-the mean visit duration and the number of revisits in each place. The association between these measures is suggested as a signature of how animals utilize different habitats or resource types. The framework is validated through computer simulations combining different movement strategies and resource maps. We suggest that the framework provides information that is especially relevant when interpreting movement data in light of optimal behavior models, and which would have remained uncovered by either coarser or finer analyses. animal movement, movement path analysis, first passage time, foraging behavior.

The residence time is the amount of time spent within a predefined circle surrounding each point along the movement path of an animal, reflecting its response to resource availability/quality. Two main residence time‐based methods exist in the literature: (1) The variance of residence times along the path plotted against the radius of the circle was suggested to indicate the scale at which the animal perceives its resources; and (2) segments of the path with homogeneous residence times were suggested to indicate distinct behavioral modes, at a certain scale. Here, we modify and integrate these two methods to one framework with two steps of analysis: (1) identifying several distinct, nested scales of area‐restricted search (ARS), providing an indication of how animals view complex resource landscapes, and also the resolutions at which the analysis should proceed; and (2) identifying places which the animal revisits multiple times and performs ARS; for these, we extract two scale‐depe...

In "The Great Migration: Insights into Savannah Animal Behaviors," readers will explore the intricate relationships between species during the seasonal movements across the savannah landscape. This compelling examination highlights the delicate balance of predator-prey dynamics, the role of biodiversity in maintaining ecosystem health, and the urgent need for conservation in the face of environmental changes.

Routine movement, defined as the repeated use of space over time, can occur in both temporal and spatial dimensions and provides valuable insight into how animals interact with their environment. Temporal routine refers to consistent revisitation of resource patches, while spatial routine describes predictable sequences of patch use. Although well documented in nectar-feeding birds and insects, these behaviors remain poorly understood in mammalian herbivores. Here, we investigated temporal and spatial routine in the Koala (Phascolarctos cinereus), a specialist arboreal folivore, and assessed how intrinsic (sex, age) and extrinsic (rainfall, vegetation productivity) factors influence these patterns. From 2015 to 2017, we GPS-tracked 25 adult koalas for up to 5 mo in a fragmented agricultural landscape in northern New South Wales, Australia. Temporal routines were identified using Fourier and wavelet analyses of presence/absence time series within core areas, while spatial routine was assessed using a conditional entropy-based routine index. Most koalas exhibited temporal routines at 2-, 7-, or 20-d intervals. Males were more likely to show short (2-d) cycles, while females more often exhibited longer (20-d) cycles. The probability of temporal routine increased under conditions of low rainfall and reduced plant productivity, suggesting a behavioral strategy to access high-value resources during environmental stress. Spatial routine was observed in only 11 individuals and declined with increasing numbers of core patches, with overall spatial predictability not exceeding that expected under random movement. This study provides the first quantitative evidence of routine temporal and spatial movement in a specialist mammalian folivore, revealing sex-specific behaviors and the influence of environmental variability on movement patterns.

BackgroundGeolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8–2.0 g total, representing 0.1–3.9 % of mean body mass) on 16 species of migratory shorebirds, including five species with 2–4 subspecies each for a total of 23 study taxa. Study species spanned a range of body sizes (26–1091 g) and eight genera, and were tagged at 23 breeding and eight nonbreeding sites. We compared breeding performance and return rates of birds with geolocators to control groups while controlling for potential confounding variables.ResultsWe detected negative effects of tags for three small-bodied species. Geolocators reduced annual return rates for two of 23 taxa: by 63 % for semipalmated sandpipers and by 43 % for the arcticola subspecies of dunlin. High resighting effort for geolocator birds could have masked additional negative effects. Geolocators were more likely to neg...

The following article* explores the meaning of roads and the practices of movement for a small group of forest inhabitants in the western Siberian lowlands on the middle Ob. The indigenous people known as the Khanty live as reindeer herders, fishermen and hunters in the midst of oilfields in the Surgut Rayon. The article examines their emic point of view opposed to the evaluation of the state administration. Anthropological research can access the mobility of people in two ways. At first researchers map movement in physical and metaphysical time and space, they observe and record the practice of movement. The second important source for anthropological insight is what people say about their practices of movement and how they evaluate them and the spaces in which they move. The following article tries to show that these perspectives remain incomplete without a synthesis of both. The first perspective allows only for a functionalist classification and the second allows the researcher to be taken in by the black and white pictures of moral evaluations that render the complexity of everyday life invisible. Only a synthesis of both, a careful interpretation of indigenous narratives before the background of social and political circumstances let us understand the practices of movement we can observe in the everyday life of people. khanty reindeer herders try to build up a distance from the world of intruders and try to defend their autonomy in the forest. By accessing everyday practices and motivations instead of ready-made explanations it is revealed that the khanty are not doomed to adapt to new situations, but they try to negotiate and manipulate them in their favour. The article tries to prove that one has to skip the objectifying approach to a hermeneutic one to grasp their abilities to do so.

BackgroundUnderstanding how environmental conditions, especially wind, influence birds' flight speeds is a prerequisite for understanding many important aspects of bird flight, including optimal migration strategies, navigation, and compensation for wind drift. Recent developments in tracking technology and the increased availability of data on large-scale weather patterns have made it possible to use path annotation to link the location of animals to environmental conditions such as wind speed and direction. However, there are various measures available for describing not only wind conditions but also the bird's flight direction and ground speed, and it is unclear which is best for determining the amount of wind support (the length of the wind vector in a bird’s flight direction) and the influence of cross-winds (the length of the wind vector perpendicular to a bird’s direction) throughout a bird's journey.ResultsWe compared relationships between cross-wind, wind suppor...

Tracking animal movements underpins our understanding of habitat linkages, stock definitions, and life-history vital rates. The bonnethead (Sphyrna tiburo) is abundant seasonally in southeastern United States (US) Atlantic coast estuaries; however, there is relatively little information regarding bonnethead ecology at the northern end of its distribution. We employed acoustic telemetry to document patterns of seasonal residency and movement for bonnetheads in North Carolina (NC) and Georgia (GA) estuaries, as well as other portions of the South Atlantic Bight (SAB). We acoustically tagged 21 bonnetheads in Beaufort Inlet Estuary, NC and 16 in Wassaw Sound, GA, and tracked those fish within estuarine arrays of 78 and 8 hydrophones in NC and GA, respectively. Bonnetheads were resident in NC and GA estuaries from March through November. Overall, detections were highly localized within individual estuaries, with most bonnetheads remaining in the area where they had been tagged, suggesting small core areas of movement (≤ 2 km) during seasonal residency. Conversely, 15 bonnetheads tagged in NC and 10 tagged in GA were detected in 14 other coastal hydrophone arrays in South Carolina, GA, and Florida (FL). The location and timing of these detections suggest that bonnetheads from distinct estuaries along the SAB overlap during late fall and winter months along the southeast US Atlantic coast, especially offshore of Brunswick, GA and Cape Canaveral, FL. Return rates for NC and GA bonnetheads were at least 25% and 19%, respectively, indicating a notable degree of estuarine-scale site fidelity.

Background Birds have extremely elevated metabolic rates during migratory endurance flight and consequently can become physiologically exhausted. One feature of exhaustion is oxidative damage, which occurs when the antioxidant defense system is overwhelmed by the production of damaging reactive oxygen species (ROS). Migrating birds have been shown to decrease the amount of oxidative lipid damage during stopovers, relatively stationary periods in between migratory flights. It has therefore been argued that, in addition to accumulating fuel, one of the functions of stopover is to restore the oxidative balance. If this is so, we would expect that migrating birds are unlikely to resume migration from stopover when they still have high amounts of lipid damage. Methods To test this hypothesis, we measured parameters of the oxidative balance and related these to stopover departure decisions of song thrushes (Turdus philomelos) and northern wheatears (Oenanthe oenanthe), a medium- and long-...

Background: The juvenile stage of loggerhead sea turtles (Caretta caretta) can last for decades. In the North Pacific Ocean, much is known about their seasonal movements in relation to pelagic habitat, yet understanding their multi-year, basin-scale movements has proven more difficult. Here, we categorize the large-scale movements of 231 turtles satellite tracked from 1997 to 2013 and explore the influence of biological and environmental drivers on basin-scale movement. Results: Results show high residency of juvenile loggerheads within the Central North Pacific and a moderate influence of the Earth's magnetic field, but no real-time environmental driver to explain migratory behavior. We suggest the Central North Pacific acts as important developmental foraging grounds for young juvenile loggerhead sea turtles, rather than just a migratory corridor. We propose several hypotheses that may influence the connectivity between western and eastern juvenile loggerhead foraging grounds in the North Pacific Ocean.

Ocean currents play an important role in the movement and distribution of organisms and for small animals it is often assumed that their movements in the ocean are determined by passive drift. Here we challenge this assumption by conducting an experiment at the scale of an entire ocean basin to test whether small (∼35 cm) juvenile loggerhead sea turtles Caretta caretta move independently of ocean currents. By comparing the trajectories of 46 satellite tracked turtles (11 502 positions, 12 850 tracking days) with Lagrangian drifters (3 716 303 positions, 927 529 tracking days) and virtual particles tracked within the Hybrid Coordinate Ocean Model (HYCOM), we found that in certain areas turtles moved in a similar manner to ocean currents, but in other areas turtle movement was markedly different from ocean currents, with turtles moving to areas thousands of kilometres from where they would have drifted passively. We further found that turtles were distributed in more-productive areas than would be expected if their movement depended on passive transport only. These findings demonstrate that regional variation in directional swimming contributes to young sea turtles reaching more favourable developmental habitats and supports laboratory work suggesting that young turtles have a map sense to determine their location in a seemingly featureless ocean.

Background The migratory process in birds consists of alternating periods of flight and fueling. Individuals of some populations make few flights and long stopovers, while others make multiple flights between short stopovers. Shorebirds are known for executing marathon flights (jumps), but most populations studied are long distance migrants, often crossing major barriers and thus forced to make long-haul flights. The sub-division of migration in short/medium distance migratory populations, where the total migration distance is shorter than documented non-stop flight capacity and where routes offer more homogenous stopover landscape, is little explored. Methods Here we combine data based on conventional light level geolocators and miniaturized multi sensor loggers, comprising acceleration and light sensors, to characterize the migratory routes and migration process for a short/medium distance (~ 1300 to 3000 km) migratory population of common ringed plover (Charadrius hiaticula) bree...

Background Biologgers have contributed greatly to studies of animal movement, behaviours and physiology. Accelerometers, among the various on-board sensors of biologgers, have mainly been used for animal behaviour classification and energy expenditure estimation. However, a general principle for the combined sampling duration and frequency for different taxa is lacking. In this study, we evaluated whether Nyquist–Shannon sampling theorem applies to accelerometer-based classification of animal behaviour and energy expenditure approximation. To evaluate the influence of accelerometer sampling frequency on behaviour classification, we annotated accelerometer data from seven European pied flycatchers (Ficedula hypoleuca) freely moving in aviaries. We also used simulated data to systematically evaluate the combined effect of sampling duration and sampling frequency on the performance of estimating signal frequency and amplitude. Results We found that a sampling frequency higher than Nyqu...

Understanding the trade-off between energy expenditure of carrying large fuel loads and the risk of fuel depletion is imperative to understand the evolution of flight strategies during long-distance animal migration. Global flyways regularly involve sea crossings that may impose flight prolongations on migrating land-birds and thereby reduce their energy reserves and survival prospects. We studied route choice, flight behavior, and fuel store dynamics of nocturnally migrating European nightjars (Caprimulgus europaeus) crossing water barriers. We show that barrier size and groundspeed of the birds influence the prospects of extended daylight flights, but also that waters possible to cross within a night regularly result in diurnal flight events. The nightjars systematically responded to daylight flights by descending to about a wingspan's altitude above the sea surface while switching to an energy-efficient flap-glide flight style. By operating within the surface–air boundary lay...

Every year, billions of seasonal migrants connect continents by transporting nutrients, energy, and pathogens between distant communities and ecosystems. For animals that power their movements by endogenous energy stores, the daily energy intake rates strongly influence the speed of migration. If access to food resources varies cyclically over the season, migrants sensitive to changes in daily energy intake rates may adjust timing of migration accordingly. As an effect, individuals adjusting to a common temporal cycle are expected to approach synchrony in foraging and movement. A large-scale periodic pattern, such as the dark-light cycle of the moon, could thus synchronize migrations across animal populations. However, such cyclic effects on the temporal regulation of migration has not been considered. Here, we show the temporal influence of the lunar cycle on the movement activity and migration tactics in a visual hunting nocturnal insectivore and long-distance migrant, the European nightjar, Caprimulgus europeaus. We found that the daily foraging activity more than doubled during moonlit nights, likely driven by an increase in light-dependent fuelling opportunities. This resulted in a clear cyclicity also in the intensity of migratory movements, with occasionally up to 100% of the birds migrating simultaneously following periods of full moon. We conclude that cyclic influences on migrants can act as an important regulator of the progression of individuals and synchronize pulses of migratory populations, with possible downstream effects on associated communities and ecosystems.

Following publication of the original article [1], the authors identified an error in the affiliation list, due to a typesetting mistake: affiliations 2 and 3 were interchanged. In addition, the authors identified an error in the captions for Tables and and in the first paragraph of the 'Interplay between method and tracking-data properties' section, due to a typesetting mistake. The text "above the double line" and "below the double line" should have been corrected to "above" and "below". The affiliation list has been updated above and the original article [1] has been corrected. The original article [1] has also been corrected with regards to the errors in the captions for Tables and and in the first paragraph of the 'Interplay between method and tracking-data properties' section. The publisher apologises to the authors and readers for the inconvenience caused by these typesetting mistakes.