Roads constrain wildlife movement and pose collision risk, yet quantifying fine-scale behavioral responses to roads remains difficult. For ungulates with large home ranges, characterizing how individuals behave during road encounters is essential for identifying where roads function as barriers and for mitigating vehicle collisions. We applied Barrier Behavior Analysis (BaBA) to GPS collar data from 125 white-tailed deer (Odocoileus virginianus) across three landscapes in southern Illinois, USA (2023–2025), to classify road encounters into behavioral types. We used mixed-effects logistic regression to examine how encounter type varied with land cover, road category, season, and diel period. We also analyzed over 250 h of camera collar videos to characterize behavior associated with each encounter type. Deer had, on average, 0.05 to 7.61 road encounters per individual per day, with nearly half of encounters involving altered behavior. Altered behavior was more likely during the day, during fawning season, on large roads, and with more forest and agricultural cover. Among the three sites, road impermeability was highest at the most forested site and lowest at the most road-dense site. Camera collar video recordings revealed behavior differences near roads. Specifically, deer were less likely to rest in videos associated with quick cross encounters (rapid road crossings without altered movement) compared to videos recorded away from roads. Roads acted as partial barriers even for a common and behaviorally flexible ungulate, altering movement in nearly half of encounters. Because road barrier strength varied with local land cover, road size, and time of day, impermeability can be resolved to individual road segments and periods when deer are least likely to cross. Camera collar video confirmed that these movement-based classifications reflect genuine differences in behavior, supporting the use of BaBA to target collision mitigation where it will be most effective.
Sickness behaviour is an important component of the response to disease and can influence how animals move through and use their environment. Such changes in behaviour may have consequences for animal ecology and, in species that serve as important hosts for infectious diseases, potentially affect disease dynamics. However, studying sickness behaviour in free-ranging animals remains challenging because it requires identifying when animals are sick while simultaneously tracking their behaviour in their natural environment. To improve our understanding of sickness behaviour in wildlife, we investigated sickness-related behavioural responses in wild mallards (Anas platyrhynchos). For this purpose, we experimentally induced an acute immune response in free-ranging mallards using lipopolysaccharide (LPS) encapsulated into biodegradable microspheres, and monitored movement patterns and habitat use for one week using GPS and accelerometry bio-loggers. We show that LPS-treated birds reduced their speed, flew shorter distances, and decreased their overall activity levels compared to control individuals, consistent with lethargy-like sickness behaviour. Furthermore, LPS-treated birds spent more time in sheltered areas and less time on open water during the peak of the acute phase response, with a potential shift in the opposite direction towards the end of the study. These findings improve our understanding of sickness behaviour in free-ranging wildlife and provide a basis for future studies investigating how sickness-related changes in movement and habitat use may affect ecological interactions and disease dynamics under natural host–pathogen contexts.
Oceanic islands can serve as predictable, high-value habitat patches in otherwise resource-sparse pelagic environments, potentially favouring different residency strategies for highly mobile, deep-diving cetaceans. By modifying local circulation and seasonal stratification, islands may influence when and where prey becomes accessible across depth layers. However, the processes linking these dynamics to individual movements and population-level aggregation in deep-diving predators remain poorly understood. We employed biotelemetry and movement models that explicitly account for location uncertainty and temporal irregularity to investigate the spatial and temporal dynamics of short-finned pilot whales (Globicephala macrorhynchus) in the Eastern North Atlantic. Sixteen biologgers deployed off Madeira Island between 2018 and 2024, transmitting data for periods ranging from 13 to 180 days (mean = 85), revealed movements across an area of 1,170,790 km2 over a cumulative 1,362 tracking days. Using a multiple-imputation hidden Markov model, we identified two distinct behavioural states: area-restricted search (ARS), which is concentrated around islands, and travelling, which occurs during offshore exploration. We then explored the relation between these states and respective transitions to two dynamic environmental covariates, sea surface temperature and mixed layer depth, with the latter showing the strongest effect on state transition probabilities. Whales were more likely to remain in or switch to ARS under shallow, stratified conditions and to switch to travelling under deeper, mixed conditions; although with inter-individual variation. The autocorrelated kernel density estimation indicated seasonal residency around Madeira (mean 53 consecutive days; max 120), producing a constrained population range (95
Marine megafauna are considered ecosystem sentinels because their distribution and demography reflect variations in prey availability and ocean productivity. Fidelity to feeding areas can therefore serve as an indicator of the long-term ecological importance and productivity of particular regions. However, assessing feeding ground fidelity in vast, open-ocean environments remains challenging, as feeding habitats are spatially diffuse and dynamic, and direct observational data are rare. Here, we investigate feeding ground fidelity in the New Zealand southern right whale (Eubalaena australis) population by integrating methods with complementary strengths and limitations: satellite telemetry and stable isotope analysis. We deployed satellite tags to track whales and used movement models to infer feeding behaviour and locations. We collected skin biopsy samples from the tagged whales, and measured tissue δ13C and δ15N isotopes. We then compared the isotope value from whale skin samples with baseline ocean phytoplankton isoscape rasters adjusted for trophic level to identify likely feeding ground associations. The whales exhibited short-term (interannual) fidelity to feeding grounds at two different spatial scales. Satellite telemetry revealed movement patterns that could be indicative of feeding behaviour across a broad region south of Australia, broadly aligning with population-level isotope assignments. At finer scales, individuals showed repeated use of highly localised sites that could represent important feeding areas. Together, these results provide direct evidence of multi-scale feeding ground fidelity in southern right whales, likely reflecting a combination of maternally transmitted migratory patterns and more flexible, short-term responses to environmental or prey-driven cues. Our findings highlight the value of integrative approaches for detecting feeding ground use and fidelity in open-ocean systems, with important implications for identifying and protecting ecologically important feeding habitats in areas beyond national jurisdiction.
Tidal fluctuations influence shorebird use of tidal flats and saltpans in coastal wetlands. Saltpans also undergo periodic water-level management, resulting in temporally varying habitat conditions during shorebird migration. However, how shorebirds shift their habitat use between tidal flats and saltpans across successive migration stages under different tidal conditions remains poorly understood. We used Kernel Density Estimation and Manly’s selectivity index, combined with GPS tracking data from 2017 to 2026 and tidal records, to quantify habitat selection patterns of the near-threatened Black-tailed Godwit (Limosa limosa) on saltpans along the Tianjin coast of Bohai Bay across four migration–management periods and two tidal conditions. Habitat selection differed significantly among the four migration–management periods for both tidal flats and saltpans under high tides (χ2 = 23.28 and 23.54, respectively; both p < 0.001) and low tides (χ2 = 19.82 and 15.47, respectively; p < 0.001 and p = 0.001). Saltpan selection increased markedly during the later stages, with selection shifting from tidal flats toward saltpans during Phase III–IV under both tidal conditions. At the individual level, core-use centroids showed a pronounced redistribution toward saltpans during Phase III–IV. At the population level, spatial hotspots progressively shifted from tidal flat areas and their adjacent zones toward saltpans (the Hangu Saltworks No. 1 Branch), with the most extensive concentration of shared use occurring during the Phase III. Our findings highlight clear stage-specific shifts in habitat selection and spatial use by Black-tailed Godwits during northward migration. These findings support phase-specific conservation management that maintains suitable shallow-water and exposed-substrate habitats in saltpan hotspots during periods of increased saltpan use. These findings may also provide a reference for phase-specific management in other saltpan systems, while specific management practices should be adjusted according to local migration progression, tidal patterns, and saltpan management schedules.
