Risk is a key currency in animal ecology, yet studies of risk have almost exclusively focused on predation. Accidents, defined as a momentary loss of control, represent another potential source of injury and mortality. Such events are seldom documented and are generally assumed to be vanishingly rare in natural systems. Nonetheless, regular crash-based mortality has been documented in a population of northern gannets through monthly surveys conducted over three years in the 1970s. We revisit these data, using hindcasting, environmental records and computational fluid dynamics (CFD) models to investigate the environmental drivers of gannet crashes, and matrix population models to examine their demographic consequences under a range of environmental scenarios. Wind direction emerged as the sole predictor of crash-based mortality, with the probability of crashes increasing in north-westerly winds. CFD models revealed that north-westerlies are associated with a marked increase in turbulent kinetic energy along the breeding cliffs, relative to the other modal wind direction, which likely challenges flight control. A total of 367 crashes accounted for 5.4% of annual adult mortality. Removing this mortality led to a projected increase in population of 23.9% over 50 years, equivalent to an additional 10,583 individuals. Overall, this suggests that turbulence close to the substrate can result in fatal losses of flight control that can impact population-level processes. Our results also highlight the need for greater understanding of how airflows influence the risk of accidents across flying animals, both in current and changing wind regimes. ### Competing Interest Statement The authors have declared no competing interest.
Phenotypic responses to climate affect individual fitness, but the extent to which this translates into effects on population dynamics remains poorly understood. We assemble 213 time series on phenotypes and population sizes of wild vertebrates globally and match them with local climate data. Our meta-analysis shows that morphological traits are mostly climate insensitive. However, phenology is earlier in warmer-than-average years, which contributes positively to population growth in most species. At lower latitudes, temperature has weaker effects on phenology but stronger direct negative effects on population growth, likely because these populations are less capable of tracking climate via plasticity. Variation in the phenology-mediated effect of temperature on population growth cannot be explained by latitude, generation time, migratory mode, or diet. This suggests that simple relationships between species characteristics and population responses to warming may not occur in nature. Instead, we may need to embrace ecological complexity by considering local-scale predictors that capture intra-specific variation.
Seabirds are exposed to numerous threats throughout their life-cycles, including land-based threats during their breeding season such as invasive species, diseases, or light pollution. Here we assess the timing, scope, and severity of land-based threats to populations of highly mobile petrels, albatrosses, storm-petrels, and alcids in the Atlantic Ocean, to guide priorities for their conservation across their mostly island-breeding areas. By combining our own field expertise of these species with a literature review, we built a dataset characterizing 18 threats for 49 species across 38 Large Marine Ecosystems. We analyze this dataset by highlighting the most impactful threats and the most impacted regions. Addressing invasive alien species on Tristan da Cunha & Gough and on the islands of the Canary Current are the interventions with the greatest potential to stimulate seabird population recovery across the Atlantic Ocean. Our results highlight priorities for targeted management actions that can support seabird conservation.
The unprecedented avian panzootic caused by High-Pathogenicity Avian Influenza (HPAI) caused widespread mortality in seabird populations, but the exact scales and patterns of transmission, basic epidemiological parameters and mortality outcomes are unknown. Mass mortalities combined with potentially detrimental sub-lethal effects of exposure will have currently unpredictable consequences for population viability of affected wild bird species, many of which are already subjected to acute anthropogenic pressures. Here, we focus on one of the most severely affected seabird species, the Northern gannet (Morus bassanus). Using a metapopulation epidemiological framework, fitted to counts of dead gannets in or near gannet breeding colonies across the NorthEast Atlantic, we estimate key epidemiological parameters, quantify spatial patterns of mortality and isolate external transmission routes. Our epidemiological parameter estimates suggest that the 2022 strains of HPAI were highly virulent and transmissible over wide geographical ranges, within the gannet network and beyond. Within gannet colonies, we found evidence that transmission rates may have declined as mortality reduced local breeding density. Inter-colony spread in the network declined with distance, and epidemiological connectivity had an estimated half-distance of 5 km. Large-scale outbreak initiation was best explained by external infection sources, most likely, other seabird species, with an estimated half-distance of 66 km. Our modelling suggests that these multi-scale, multispecies processes resulted in 28% (95% CI: 21%-34%) HPAI-mortality across the Northeast Atlantic gannet breeding metapopulation, in addition to normal levels of annual mortality (5%-10%). Our study demonstrates that if analysed holistically, carcass data can provide epidemiological insights but also act as an early warning system for continent-wide patterns of spread. For pandemic preparedness, it is essential that data-integrative approaches such as ours are placed in the mainstream toolbox of planetary health monitoring. By disentangling intra- and inter-specific transmission, our approach highlights the need to integrate colonial species into global avian influenza surveillance and response.
The form, magnitude and temporal dynamics of selection on phenotypic plasticity will fundamentally shape eco-evolutionary responses to environmental variation, but such attributes have not been fully conceptualized or quantified in nature. We provide a general framework that conceptualizes the dynamics of selection on phenotypic plasticity in labile dichotomous traits, which commonly shape behaviour and life history. Specifically, we highlight distinctions between selection on expressed plasticity and selection on resulting phenotypes, effects of phenotypic switches in opposite directions, and the full selection dynamics emerging across temporal sequences of environmental conditions. To enact this framework, we quantified selection on early-life plasticity in the ecologically critical trait of seasonal migration versus residence, by fitting a novel multi-state model to spatio-seasonal resighting data from 13 newly fledged cohorts of partially migratory European shags (Gulosus aristotelis). We demonstrate strong and consistent directional selection against early-life plasticity, manifested as substantially lower juvenile survival after phenotypic switches from resident to migrant, but not after reverse switches from migrant to resident. Yet, evident short-term costs translated into weaker and fluctuating selection on plasticity given sequences of phenotypes expressed throughout initial months. We thereby reveal how complex forms of selection against early-life plasticity can arise yet be rapidly attenuated in nature.
Declining body sizes are prevalent in marine fish and have been suggested to be a response to increasing temperatures. However, the evidence is mixed, and the underlying causes are often unknown. Here, we explore drivers of spatio-temporal patterns in size in juvenile lesser sandeel Ammodytes marinus, focusing on ongoing size declines in parts of the North Sea. We combine experimental and field data with theory to develop a biologically realistic dynamic energy budget model that explicitly models feeding, metabolism and energy allocation to produce daily predictions of sandeel length during the growth season from 1979 to 2016 in 4 North Sea sub-populations. When forced with daily temperature estimates and zooplankton data from the Continuous Plankton Recorder, model predictions largely match observed spatio-temporal patterns. Our results suggest that the most plausible driver of observed size declines in the western North Sea is declining prey densities. In contrast, the direct effect of temperature on sandeel size is small but interacts with local prey availability so that increasing temperatures may boost growth rates in areas with high food availability but reduce growth rates in areas with low food availability. Our results thus suggest that to understand the effects of climate change on fish size, we need to account for both direct physiological effects and changes in resource availability. Finally, we show that early-life phenology and turbidity (via its impact on intake rates in the visually foraging sandeel) may also impact sandeel size, highlighting the importance of broadening our view of potential drivers of size declines.
Life-history traits expressed in early life can exhibit considerable among-cohort variation, which could substantially affect population age-structure and dynamics if initial variation persists into later life-stages. Yet, initial among-cohort variation could be reinforced, rapidly dissipated, or else completely reshaped by dynamic combinations of age-specific phenotypic plasticity and selective disappearance acting within and among cohorts. However, such effects have not been comprehensively quantified for any trait, precluding full prediction of the form and implications of phenotypic dynamics, and emerging age-specific life-history variation, in varying environments. We provide a framework for conceptualising phenotypic change resulting from joint and interacting effects of cohort-specific and age-specific plasticity and selective disappearance. We implement this framework by quantifying overall early-life age-specific phenotypic change (or stasis), and dissecting underlying dynamics of plasticity and selection, for the ecologically critical life-history trait of seasonal migration versus residence. We achieve this by fitting multi-state models to extensive multi-year ring-resighting data from 9358 colour-ringed European shags (Gulosus aristotelis) from 11 cohorts in a partially migratory population. The overall cross-cohort mean proportion of migrants versus residents remained approximately constant across the four winters following fledging, implying no overall change in the degree of seasonal migration with age. This stasis was underlain by consistently high cross-year individual phenotypic repeatability, and by average plasticity towards residence that was counter-acted by average selective disappearance of sub-adult residents. However, these cross-cohort means obscured substantial among-cohort variation in the initial degree of partial migration, and in subsequent joint effects of plasticity and selective disappearance. Here, plasticity and selection were not systematically associated within or across cohorts or ages, but rather reinforced versus counter-acted each other at different times, thereby reshaping the pattern of among-cohort variation in partial migration across ages. These results demonstrate that an absence of overall age-specific change in a key life-history trait, seasonal migration versus residence, obscures substantial underlying variation in both early-life plasticity and selective disappearance, generating complex phenotypic dynamics within individual cohorts. Standard cross-cohort analyses may therefore inadequately predict future spatio-seasonal dynamics, since novel age-specific life-histories could readily emerge given changing environmental drivers of plasticity and selection.
In iteroparous, socially monogamous species, individuals vary in the extent of mate fidelity across breeding attempts, often with important fitness consequences. Numerous studies have demonstrated intrinsic drivers of mate fidelity, notably previous breeding success and parental age. Environmental conditions may also influence mate fidelity, and the habitat-mediated hypothesis predicts that fidelity will be lower when environmental conditions are poor. However, limited testing of this hypothesis has been undertaken in longitudinal studies of single populations. Furthermore, studies have mainly focused on environmental conditions during the breeding season, yet conditions prior to breeding may be important for mate fidelity because this is a critical period for pair bond formation. We investigated the effects of prebreeding environmental conditions (onshore wind component and sea surface temperature) on mate fidelity over a 20-year period in the socially monogamous, iteroparous, long-lived marine bird, the European shag, Gulosus aristotelis. Average fidelity rate varied three-to four-fold between years. Mate fidelity was affected by prebreeding environmental conditions, being lower when onshore winds were more prevalent and sea surface temperature was higher. However, mate fidelity was more strongly affected by intrinsic factors, with higher rates when breeding success in the previous attempt and population density were higher, and among older females and middle-aged males. We found that mate fidelity affected timing of breeding, with faithful pairs laying earlier, and early laying pairs bred more successfully, but there was no independent effect of mate fidelity on breeding success. Our results support the habitat-mediated hypothesis whereby prebreeding environmental conditions affect individual pairing decisions. Given environmental conditions are predicted to change globally, further investigation of their impact on aspects of social behaviour in a range of species is warranted. Crown Copyright (c) 2025 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY license (http://creativecommons.org/licenses/ by/4.0/).
Declining body sizes are prevalent in marine fish. While these declines have been suggested to be a response to increasing temperatures, the evidence is mixed and the underlying causes of observed declines often unknown. Here, we explore drivers of spatio-temporal patterns in size in lesser sandeel (Ammodytes marinus), an important prey for seabirds and marine mammals, focusing on ongoing size declines in the North Sea. We combine experimental and field data with ecological theory to develop a biologically realistic dynamic energy budget model that explicitly models feeding, metabolism and energy allocation to produce daily predictions of size during the juvenile growth season from 1979 to 2016. When forced with daily temperature estimates and zooplankton data from the Continuous Plankton Recorder, model predictions reproduce observed spatio-temporal patterns in size well. Our results suggest that the most plausible driver of observed size declines in the western North Sea is declining prey densities. In contrast, the direct effect of temperature on sandeel size is small, but interacts with local prey availability so that the effect varies in both size and direction over space. Our results thus suggest that to understand effects of climate change on fish size we need to account for both direct physiological effects and changes in resource availability. Finally, we use the model to show that early-life phenology and turbidity (via its impact on intake rates in the visually foraging sandeel) may also impact sandeel size, highlighting the importance of broadening our view of potential drivers of size declines. ### Competing Interest Statement The authors have declared no competing interest.
Ecosystem structure and biophysical processes mediate biological responses to climate changes, but few studies have examined impacts of this dynamic among upper trophic levels. We investigated ecosystem differences in how diverse seabird populations across the northern hemisphere have responded to changes in regional mixed layer temperature and water column stratification. Using 138 time series of breeding productivity over the past half-century, we show that seabird reproductive productivity has declined in the Arctic and North Atlantic but not in the Pacific during a period of ubiquitous mixed layer warming and regionally-variable stratification trends. Models of breeding productivity and ocean drivers show that seabird responses to climate change vary by ecosystem. Additionally, ecosystems in which seabirds exhibit detectibly declining productivity tend to have lower overall diet diversity across seabird species. These findings emphasize the importance of ecosystem processes and structure in determining the vulnerability of marine predators to climate change.
Highly pathogenic avian influenza (HPAIV) caused widespread mortality and breeding failure among many wild, avian populations in Europe and North America in 2021-2023, but most populations exhibited a marked reduction in mortality in the year following an outbreak, suggesting that surviving individuals may have developed immunity. A critical mechanism for population resilience is whether individuals that have survived the disease show reduced breeding success because of the potential costs associated with recovery, notably elevated immune defence. We found that, at two UK colonies, the breeding success of Northern Gannets Morus bassanus with black eyes (an indicator of past exposure to HPAIV) was similar to those with normal blue eyes in the year following a severe disease outbreak, suggesting that population recovery may not be hampered by lower reproductive performance of recovered individuals compared to those that were unexposed. However, breeding success, irrespective of past exposure, was lower than the long-term average, suggesting potential carry-over effects on all individuals from the extensive disruption caused by the epidemic the previous year.
Understanding the responses of seabirds to climate-induced variations in phenology and abundance of their prey is key to developing ecosystem-based fisheries management measures that benefit higher trophic levels. The match/mismatch hypothesis (MMH) emphasizes the need to consider synchrony in the seasonal cycles of predators and prey, while the match/mismatch/abundance hypothesis (MMAH) proposes that prey abundance may reinforce/compensate mismatch effects. This study considers the effects of both variations in seasonal availability and abundance of lesser sandeel Ammodytes marinus on hatching, fledging and breeding success of 5 seabird species: black-legged kittiwake Rissa tridactyla , Atlantic puffin Fratercula arctica , razorbill Alca torda , common guillemot Uria aalge and European shag Gulosus aristotelis . Consistent with MMH, temporal asynchrony between sandeel availability and seabird breeding schedules affected productivity in 4 species. The effects of trophic asynchrony were either reinforced or compensated by sandeel abundance for some species, supporting MMAH. Breeding success in the late-breeding kittiwake was high when conditions favoured both high sandeel abundance and temporal synchrony while the cost of asynchrony could be compensated by high sandeel abundance in the earlier-breeding puffin. Differential effects of sandeel abundance and trophic synchrony at different stages of the seabird breeding season suggest that distinct mechanisms are involved. The effects were most evident in the most sandeel-reliant seabirds. As further disruption of sandeel phenology and abundance is anticipated under the current climate crisis, the present study is an important step towards understanding bottom-up effects of environmental change on higher trophic levels.
To acquire or retain a higher quality breeding site, individuals may occupy sites outside the breeding season, with those investing more time and energy in this benefiting from improved breeding success. However, despite this benefit, the occupancy patterns of individuals may vary. Occupancy may be influenced by the distance individuals travel from breeding sites during the nonbreeding season; individuals nearer the colony may undertake occupancy earlier and more frequently than conspecifics because of shorter commuting distances from migration and foraging locations. Occupancy may also be energetically costly and affect how individuals are able to allocate their time to other key behaviours such as foraging. However, our understanding of how occupancy behaviour relates to an individual's distribution and ability to balance time and energy allocated to other behaviours is limited. Using data from a population of common guillemots, Uria aalge, a colonially breeding seabird, on the Isle of May, U.K., we investigated how nonbreeding occupancy of breeding sites is related to at-sea distribution, and how much energy and time individuals allocate to behaviours throughout the nonbreeding season We used bird-borne geolocators and time-depth recorders to record distribution and estimate time allocated to behaviours including occupancy, flight and foraging. Individuals that remained nearer to the colony before their first return then returned earlier and had shorter bouts of absence thereafter. Individuals also experienced a trade-off in the time spent in occupancy or foraging. Our data allowed us to estimate the increase in foraging efficiency required to offset the lost foraging time in individuals that occupied breeding sites. Overall, despite its known benefits, individuals varied in their timing and pattern of occupancy. We suggest that achieving consistently high breeding success, via nonbreeding season occupancy, may depend on an individual's distribution and ability to forage efficiently throughout the nonbreeding season. (c) 2024 The Authors. Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.
Drones are an increasingly popular choice for wildlife surveys due to their versatility, quick response capabilities, and ability to access remote areas while covering large regions. A novel application presented here is to combine drone imagery with neural networks to assess mortality within a bird colony. Since 2021, Highly Pathogenic Avian Influenza (HPAI) has caused significant bird mortality in the UK, mainly affecting aquatic bird species. The world’s largest northern gannet colony on Scotland’s Bass Rock experienced substantial losses in 2022 due to the outbreak. To assess the impact, RGB imagery of Bass Rock was acquired in both 2022 and 2023 by deploying a drone over the island for the first time. A deep learning neural network was subsequently applied to the data to automatically detect and count live and dead gannets, providing population estimates for both years. The model was trained on the 2022 dataset and achieved a mean average precision (mAP) of 37%. Application of the model predicted 18,220 live and 3761 dead gannets for 2022, consistent with NatureScot’s manual count of 21,277 live and 5035 dead gannets. For 2023, the model predicted 48,455 live and 43 dead gannets, and the manual count carried out by the Scottish Seabird Centre and UK Centre for Ecology and Hydrology (UKCEH) of the same area gave 51,428 live and 23 dead gannets. This marks a promising start to the colony’s recovery with a population increase of 166% determined by the model. The results presented here are the first known application of deep learning to detect dead birds from drone imagery, showcasing the methodology’s swift and adaptable nature to not only provide ongoing monitoring of seabird colonies and other wildlife species but also to conduct mortality assessments. As such, it could prove to be a valuable tool for conservation purposes.
Knowledge of seabird distributions plays a key role in seabird conservation and sustainable marine management, underpinning efforts to designate protected areas or assess the impact of human developments. Technological advances in animal tracking devices increasingly allow researchers to acquire information on the movement of birds from specific colonies. Nevertheless, most seabird colonies have not been subject to such tracking and another means must be found to assess their likely foraging distribution. Consequently, foraging range data collated and summarized across other tracking studies has often been used to estimate species‐level foraging distances for use within applied settings. However, generic species‐specific foraging ranges must be used with caution because of the amount of variation in seabird foraging behaviour at both the individual and colony levels. Specifically, although current reviews of seabird foraging ranges provide summary estimates of maximum foraging range, they typically do not assess the extent of among‐colony or among‐individual variation around such estimates. To address this, we conducted a variance component analysis of the maximum distance reached from the breeding colony per foraging trip (foraging range) using multi‐colony tracking datasets to estimate the degree of between‐individual, between‐year and between‐colony variation in foraging range in four UK breeding seabirds (Black‐legged Kittiwake Rissa tridactyla , Common Guillemot Uria aalge , Razorbill Alca torda and European Shag Gulosus aristotelis ). We also provide updated estimates of typical foraging ranges for each species and quantify the influence of breeding stage and colony size. Overall, between‐colony variation was typically the largest variance component, explaining 20–30% of the observed variation in foraging range across the four species. Individual‐level variation was also relatively large among Shag. In Kittiwake, Guillemot and Shag, but not Razorbill, average foraging ranges were positively associated with colony size. In addition, Kittiwake and Razorbill travelled further during incubation than during chick‐rearing. More generally, our estimates of mean foraging ranges for each species were subject to a high degree of uncertainty, which should be incorporated into impact assessments carried out using such data.
Density-dependent competition for food influences the foraging behaviour and demography of colonial animals, but how this influence varies across a species’ latitudinal range is poorly understood. Here we used satellite tracking from 21 Northern Gannet Morus bassanus colonies (39% of colonies worldwide, supporting 73% of the global population) during chick-rearing to test how foraging trip characteristics (distance and duration) covary with colony size (138–60 953 breeding pairs) and latitude across 89% of their latitudinal range (46.81–71.23° N). Tracking data for 1118 individuals showed that foraging trip duration and maximum distance both increased with square-root colony size. Foraging effort also varied between years for the same colony, consistent with a link to environmental variability. Trip duration and maximum distance also decreased with latitude, after controlling for colony size. Our results are consistent with density-dependent reduction in prey availability influencing colony size and reveal reduced competition at the poleward range margin. This provides a mechanism for rapid population growth at northern colonies and, therefore, a poleward shift in response to environmental change. Further work is required to understand when and how colonial animals deplete nearby prey, along with the positive and negative effects of social foraging behaviour.
AimEcologically similar species living in sympatry are expected to segregate to reduce the effects of competition where resources are limiting. Segregation from heterospecifics commonly occurs in space, but it is often unknown whether such segregation has underlying environmental causes. Indeed, species could segregate because of different fundamental environmental requirements (i.e., 'niche divergence'), because competitive exclusion at sympatric sites can force species to either change the habitat use they would have at allopatric sites (i.e., 'niche displacement') or to avoid certain areas, independently of habitat (i.e., 'spatial avoidance'). Testing these hypotheses requires the comparison between sympatric and allopatric sites. Understanding the competitive mechanisms that underlie patterns of spatial segregation could improve predictions of species responses to environmental change, as competition might exacerbate the effects of environmental change.LocationNorth Atlantic and Arctic.TaxaCommon guillemots Uria aalge and Br & uuml;nnich's guillemots Uria lomvia.MethodsHere, we examine support for these explanations for spatial segregation in two closely-related seabird species, common guillemots (Uria aalge) and Br & uuml;nnich's guillemots (U. lomvia). For this, we collated a pan-Atlantic data set of breeding season foraging tracks from 1046 individuals, collected from 20 colonies (8 sympatric and 12 allopatric). These were analysed with habitat models in a spatially transferable framework to compare habitat preferences between species at sympatric and allopatric sites.ResultsWe found no effect of the distribution of heterospecifics on local habitat preferences of the focal species. We found differences in habitat preferences between species, but these were not sufficient to explain the observed levels of spatial segregation at sympatric sites.Main ConclusionsAssuming we did not omit any relevant environmental variables, these results suggest a mix of niche divergence and spatial avoidance produces the observed patterns of spatial segregation.
Disease outbreaks can drastically disturb the environment of surviving animals, but the behavioural, ecological, and epidemiological consequences of disease-driven disturbance are poorly understood. Here, we show that an outbreak of High Pathogenicity Avian Influenza Virus (HPAIV) coincided with unprecedented short-term behavioural changes in Northern gannets (Morus bassanus). Breeding gannets show characteristically strong fidelity to their nest sites and foraging areas (2015–2019; n = 120), but during the 2022 HPAIV outbreak, GPS-tagged gannets instigated long-distance movements beyond well-documented previous ranges and the first ever recorded visits of GPS-tagged adults to other gannet breeding colonies. Our findings suggest that the HPAIV outbreak triggered changes in space use patterns of exposed individuals that amplified the epidemiological connectivity among colonies and may generate super-spreader events that accelerate disease transmission across the metapopulation. Such self-propagating transmission from and towards high density animal aggregations may explain the unexpectedly rapid pan-European spread of HPAIV in the gannet.
BACKGROUND:Fidelity to a given foraging location or route may be beneficial when environmental conditions are predictable but costly if conditions deteriorate or become unpredictable. Understanding the magnitude of fidelity displayed by different species and the processes that drive or erode it is therefore vital for understanding how fidelity may shape the demographic consequences of anthropogenic change. In particular, understanding the information that individuals may use to adjust their fidelity will facilitate improved predictions of how fidelity may change as environments change and the extent to which it will buffer individuals against such changes.METHODS:We used movement data collected during the breeding season across eight years for common guillemots, Atlantic puffins, razorbills, and black-legged kittiwakes breeding on the Isle of May, Scotland to understand: (1) whether foraging site/route fidelity occurred within and between years, (2) whether the degree of fidelity between trips was predicted by personal foraging effort, and (3) whether different individuals made more similar trips when they overlapped in time at the colony prior to departure and/or when out at sea suggesting the use of the same local environmental cues or information on the decisions made by con- and heterospecifics.RESULTS:All species exhibited site and route fidelity both within- and between-years, and fidelity between trips in guillemots and razorbills was related to metrics of foraging effort, suggesting they adjust fidelity to their personal foraging experience. We also found evidence that individuals used local environmental cues of prey location or availability and/or information gained by observing conspecifics when choosing foraging routes, particularly in puffins, where trips of individuals that overlapped temporally at the colony or out at sea were more similar.CONCLUSIONS:The fidelity shown by these seabird species has the potential to put them at greater risk in the face of environmental change by driving individuals to continue using areas being degraded by anthropogenic pressures. However, our results suggest that individuals show some flexibility in their fidelity, which may promote resilience under environmental change. The benefits of this flexibility are likely to depend on numerous factors, including the rapidity and spatial scale of environmental change and the reliability of the information individuals use to choose foraging sites or routes, thus highlighting the need to better understand how organisms combine cues, prior experience, and other sources of information to make movement decisions.