Bright coloration in predators presents a paradox: being highly visible should reduce hunting success, yet vivid colors persist in species that rely on stealth. Camouflage, which minimizes contrast with the background, and startle coloration, where sudden brightness disrupts prey escape, have been proposed to explain this paradox. Barn owls (Tyto alba) are polymorphic, ranging from dark reddish to bright white, offering a natural experiment. Using high-resolution biologging, we tracked 69 free-ranging males across 354 nights and recorded 17,600 hunting attempts during chick provisioning. We tested whether plumage color mediates moonlight-dependent hunting behavior and performance. White males reduced exposure under dim conditions but, under bright moonlight, oriented attacks toward the Moon and favored bright periods and unshaded sites throughout the night. Red males showed weaker or no adjustments and remained comparatively cryptic. Although per-attack success did not differ across the lunar gradient, white males achieved higher nightly prey capture rates and shorter foraging bouts under bright moonlight. Together with previous work, these patterns are more consistent with the startle hypothesis than with a pure background-matching scenario, suggesting that conspicuous plumage can be incorporated into a light-dependent hunting strategy and that variation in lunar lightscapes may influence the evolution of animal coloration.

The "Tool for Agroecology Performance Evaluation" (TAPE) was developed under the coordination of the Food and Agriculture Organisation of the United Nations (FAO) to assess the sustainability performance of agroecosystems. The assessment is mainly based on a 2-3-hour farm interview, in which a wide variety of data is collected. The environmental dimension has so far been represented in TAPE by two simple indices: A soil index, which is based on a visual analysis of the soil, and a biodiversity index, which is primarily based on the Gini-Simpson index of crops grown and animals kept. While the TAPE biodiversity index is crucial, it does not yet take into account so-called unplanned biodiversity, i.e. the impact of on-farm management practices on wild species. We have therefore expanded TAPE to include this aspect. Direct surveys of wildlife biodiversity in the field were not possible in TAPE, as this would have far exceeded the time required for data collection. Consequently, we based the newly developed biodiversity index on the indirect European BioBio method. The new index consists of ten indicators, which can take values between 0 and 100% and be aggregated to form the overall index. Examples of these indicators are field size, nitrogen application or stocking density. The new index was developed and tested on selected Swiss farms, where the comparison with a much more comprehensive and time-consuming method showed a positive correlation (r = 0.56, p-value = 0.009). The new index has so far been used in Switzerland (21 farms) and in Kenya (103 farms). In Switzerland, the field size and land use change indicators performed best (values > 75%), while the indicators tree habitat, nitrogen application, field operations and grazing intensity performed poorly (values > 50%). In Kenya, the field size, land use change, pesticide and field operations indicators reached values above 75%, while the tree habitat, grazing intensity and semi-natural habitat indicators had values clearly below 50%.

Predator-prey arms races have led to the evolution of finely tuned disguise strategies. While the theoretical benefits of predator camouflage are well established, no study has yet been able to quantify its consequences for hunting success in natural conditions. We used high-resolution movement data to quantify how barn owls (Tyto alba) conceal their approach when using a sit-and-wait strategy. We hypothesized that hunting barn owls would modulate their landing force, potentially reducing noise levels in the vicinity of prey. Analysing 87,957 landings by 163 individuals equipped with GPS tags and accelerometers, we show that barn owls reduce their landing force as they approach their prey, and that landing force predicts the success of the following hunting attempt. Landing force also varied with the substrate, being lowest on man-made poles in field boundaries. The physical environment, therefore, affects the capacity for sound camouflage, providing an unexpected link between predator-prey interactions and land use. Finally, hunting strike forces in barn owls were the highest recorded in any bird, relative to body mass, highlighting the range of selective pressures that act on landings and the capacity of these predators to modulate their landing force. Overall, our results provide the first measurements of landing force in a wild setting, revealing a new form of motion-induced sound camouflage and its link to hunting success.

Aim: Climatic gradients shape geographic variation in phenotypic traits that are involved in animal thermoregulation. Therefore, increasing temperatures under global warming are expected to cause change over time in traits that show predictable spatial patterns according to environmental clines (body and appendage size, tegument coloration), as well exemplified by biogeographic rules and shown by increasing literature at a local scale. However, whether temporal shifts in phenotypic traits vary spatially according to the magnitude of the change in local climatic conditions is still unknown. Location: World. Taxon: Barn owl species complex (Tyto alba group). Methods: By using thousands of museum specimens collected across the globe from 1901 to 2018, we calculated within-population change over time in wing length, bill length and melanin-based plumage coloration and examined whether these trends differed across geographic regions, latitudes and gradients of climate changes. Results: We showed that populations exposed to an increasing warmer climate were subjected to a more marked decrease in body size, as gauged by wing length, and also absolute bill length that displayed a similar, although less steep, pattern of shrinking over time. In addition, phaeomelanin-based ventral plumage colour has become paler in regions where the climate changed into warmer and drier, and darker where both temperature and precipitation increased. Main Conclusions: These trends are generally coherent with the predictions based on Bergmann's and Gloger's rules, but not Allen's rule, and suggest that temporal shifts in body size and tegument colour depend on the magnitude of the alteration in climatic conditions, with populations living in regions where the climate has changed the most that are subjected to more marked phenotypic changes. Spatio-temporal variation in climate has driven within-species phenotypic clines, and it is expected to increase differences among populations according to the predicted further climate change.

Ecosystem services and biodiversity are frequently measured by field-scale indicators. Yet, many important agricultural and economic drivers as well as agri-environmental policies operate at larger sales, to which field-scale indicators first need to be upscaled. Therefore, this perspective is focussed on upscaling approaches from field to farm or to landscape scale. To understand how ecosystem services and biodiversity are affected by farm-scale drivers and to inform future decision- and policy-making while exploiting existing data sources, these need to be upscaled and analysed at farm scale. However, how this is done best for different types of indicators for ecosystems services and biodiversity received little attention so far.In this work, we propose and discuss different options for upscaling ecosystem service and biodiversity indicators from field to farm scale. We base our novel conceptual work on a large body of literature and demonstrate that before deciding on an upscaling approach, different aspects of the indicators and the purpose of the assessment need to be considered. Our propositions start at the point where field-scale data is available for aggregation at farm scale. Such an aggregation needs to consider the relationship between ecosystem service supply and the benefit provided, i.e., the supply-benefit relationship, which describes how a change in supply affects the resulting benefit for farmers and/or society. We argue that this relationship can also be conceptualized for biodiversity, with benefit being the value of a field or farm for biodiversity conservation.Because benefit does often not continuously increase with supply, but can exhibit breaking points defined by thresholds in supply, the shape of the supply-benefit relationship varies among different ecosystem services and biodiversity components. For example, for upscaling biodiversity indicators, a conservation value needs to consider that conservation benefit might non-linearly change with supply, i.e., habitat quality and quantity, and becomes marginal below certain thresholds. Only when such potential thresholds are considered, a suitable upscaling approach can be chosen from the approaches that we present in this work. While some indicators can be upscaled using a simple area-weighted total or average, for others, thresholds in supply are of great relevance for determining the best upscaling approach. We conclude that upscaling indicators to the farm scale holds untapped potential to inform agri-environmental assessments and future policies. By presenting and discussing suitable approaches for different types of indicators, we hope to facilitate upscaling as a tool to support agri-environmental decision-making in the future.

Background: The intensification of the agricultural practices in Europe over the last decades has drastically transformed the agroecosystems. The simplification of the landscape, the loss of semi-natural habitats and the application of chemicals on crops are known to have led to biodiversity decline in agricultural landscapes, raising substantial concerns about the loss of essential ecosystem services, such as pollination or pest control. Depending on the location, the scale and the regional context, different indicator species groups (ISGs) are often surveyed to assess the state and trend of biodiversity changes in agroecosystems. Although the high diversity of these ISGs allows a broad overview of the biodiversity, it complicates the interpretation of the results and thus their application. In addition, species diversity metrics are various, from simple species counts to more complex measurements of diversity indices, sometimes with antagonistic responses. Here, to meet the pressing need for synthesis in this complex topic, we will follow a standardized systematic map protocol to collect and summarize the literature reporting the effects of the main European lowland agricultural management practices (AMPs) on a set of ISGs. Methods: Following the systematic evidence synthesis standards, we developed the question to address in the systematic map using the PICO framework. We established a preliminary search string by combining search terms for the categories Population (ISGs), Intervention (AMPs) and Outcome (species diversity), as well as with two additional groups (Environment-to focus on lowland crop and grassland-and Location-to restrict the study area to Europe). We will conduct a comprehensive literature search of relevant peer-reviewed and grey literature using Web of Science and CABI platforms, Google Scholar, specialized websites and through our professional collaborator network. The comprehensiveness of the search will be assessed by comparing the literature collected to a test-list of ninety relevant articles. The repeatability of the literature screening process will be ensured by a list of inclusion/exclusion criteria and inter-reviewer consistency statistical tests. Data extraction will be organized in three complementary tables (article references, study characteristics, species diversity), on which we will perform queries to produce the tables, figures and maps that will compose the systematic map.

Background For resident birds of prey in the temperate zone, the cold non-breeding period can have strong impacts on survival and reproduction with implications for population dynamics. Therefore, the non-breeding period should receive the same attention as other parts of the annual life cycle. Birds of prey in intensively managed agricultural areas are repeatedly confronted with unpredictable, rapid changes in their habitat due to agricultural practices such as mowing, harvesting, and ploughing. Such a dynamic landscape likely affects prey distribution and availability and may even result in changes in habitat selection of the predator throughout the annual cycle. Methods In the present study, we (1) quantified barn owl prey availability in different habitats across the annual cycle, (2) quantified the size and location of barn owl breeding and non-breeding home ranges using GPS-data, (3) assessed habitat selection in relation to prey availability during the non-breeding period, and (4) discussed differences in habitat selection during the non-breeding period to habitat selection during the breeding period. Results The patchier prey distribution during the non-breeding period compared to the breeding period led to habitat selection towards grassland during the non-breeding period. The size of barn owl home ranges during breeding and non-breeding were similar, but there was a small shift in home range location which was more pronounced in females than males. The changes in prey availability led to a mainly grassland-oriented habitat selection during the non-breeding period. Further, our results showed the importance of biodiversity promotion areas and undisturbed field margins within the intensively managed agricultural landscape. Conclusions We showed that different prey availability in habitat categories can lead to changes in habitat preference between the breeding and the non-breeding period. Given these results we show how important it is to maintain and enhance structural diversity in intensive agricultural landscapes, to effectively protect birds of prey specialised on small mammals.

Recent biologging technology reveals hidden life and breeding strategies of nocturnal animals. Combining animal movement patterns with individual characteristics and landscape features can uncover meaningful behaviours that directly influence fitness. Consequently, defining the proximate mechanisms and adaptive value of the identified behaviours is of paramount importance. Breeding female barn owls ( Tyto alba ), a colour-polymorphic species, recurrently visit other nest boxes at night. We described and quantified this behaviour for the first time, linking it with possible drivers, and individual fitness. We GPS-equipped 178 breeding pairs of barn owls from 2016 to 2020 in western Switzerland during the chick rearing phase. We observed that 65% of breeding females tracked were (re)visiting nest boxes while still carrying out their first brood. We modelled their prospecting parameters as a function of partner-, individual- and brood-related variables, and found that female feather eumelanism predicted the emergence of prospecting behaviour (less melanic females are usually prospecting), while increasing male parental investment increased female exploratory efforts. Ultimately, females would revisit a nest more often if they had used it in the past and were more likely to lay a second clutch afterwards, consequently having higher annual fecundity than non-prospecting females. Despite these apparent immediate benefits, they did not fledge more chicks. We highlight how phenotypic traits can be related to movement patterns and individual fitness through biologging associated with long-term field monitoring. ### Competing Interest Statement The authors have declared no competing interest.

Recent biologging technology reveals hidden life and breeding strategies of nocturnal animals. Combining animal movement patterns with individual characteristics and landscape features can uncover meaningful behaviours that directly influence fitness. Consequently, defining the proximate mechanisms and adaptive value of the identified behaviours is of paramount importance. Breeding female barn owls (Tyto alba), a colour-polymorphic species, recurrently visit other nest boxes at night. We described and quantified this behaviour for the first time, linking it with possible drivers, and individual fitness. We GPS-equipped 178 female barn owls and 122 male partners from 2016 to 2020 in western Switzerland during the chick rearing phase. We observed that 111 (65%) of the tracked breeding females were (re)visiting nest boxes while still carrying out their first brood. We modelled their prospecting parameters as a function of brood-, individual- and partner-related variables and found that female feather eumelanism predicted the emergence of prospecting behaviour (less melanic females are usually prospecting). More importantly we found that increasing male parental investment (e.g., feeding rate) increased female prospecting efforts. Ultimately, females would (re)visit a nest more often if they had used it in the past and were more likely to lay a second clutch afterwards, consequently having higher annual fecundity than non-prospecting females. Despite these apparent immediate benefits, they did not fledge more chicks. Through biologging and long-term field monitoring, we highlight how phenotypic traits (melanism and parental investment) can be related to movement patterns and the annual potential reproductive output (fecundity) of female barn owls.

AimPheomelanin is a pigment responsible for yellowish-to-reddish colours of vertebrate teguments. Its biosynthesis is favoured under high concentration of intracellular thiols, which, in turn, can depend on the environmental exposure to sulphur. Thus, pheomelanin production should be more intense and frequent in environments characterized by high level of sulphur, such as volcanic regions. In this study, we aimed at addressing this hypothesis by investigating variation in plumage colour of insular populations of the cosmopolitan barn owl (Tyto alba species complex) according to the presence of soils of volcanic origin (i.e. andosols) and recent volcanic activity. LocationWorld. TaxonBarn owl species complex. MethodsWe measured plumage colouration of more than 2000 museum specimens from 50 islands and archipelagos worldwide. We then compared plumage colouration between populations living on volcanic (i.e. where andosols and/or recent volcanic activity are present) and non-volcanic islands/archipelagos. ResultsConsistently with the prediction, plumage colouration is significantly darker (i.e. pheomelanic) on islands/archipelagos where andosols and/or recent volcanic activity are present than absent, although this environmental factor explains a small fraction of plumage colour variability across islands (<10%). Similar results were obtained when specimens' sex and climatic predictors were included in the analyses. Main ConclusionsBecause excessive intracellular levels of thiols can be toxic, pheomelanin synthesis may function as a mechanism keeping these compounds below the toxicity threshold and limiting their detrimental effects on physiology. Darker plumage may also be favoured because it promotes background matching against the dark environment typical of volcanic islands (dense vegetation cover and/or dark soil). Our results add to the little evidence that the environmental exposure of compounds that are involved in melanin biosynthesis can affect animal pigmentation and suggest that soil composition may be a factor that affects melanogenesis, possibly contributing to generate spatial variation in pheomelanin-based traits in animals.

Abstract Background: For sedentary birds of prey in the temperate zone, the cold non-breeding season can have strong impacts on fitness traits with implications for population dynamics. The non-breeding season should thus receive the same attention as other parts of the annual life cycle. Birds of prey in intensively managed agricultural areas are repeatedly confronted with unpredictable, rapid changes to their habitat due to farming practices like mowing, harvesting, and ploughing. Such a dynamic landscape is likely to influence prey distribution and availability and might even result in changes in habitat selection of the predator over the annual cycle. Methods: In the present study, we 1) quantified barn owl prey availability in different habitats throughout the annual cycle, 2) quantified the size and location of barn owl breeding and non-breeding home ranges using GPS-data, 3) assessed habitat selection in relation to prey availability during the non-breeding period, and 4) discussed the changes in habitat selection between the breeding and non-breeding period.Results: The patchier prey distribution during the non-breeding period compared to the breeding period led to habitat selection towards grassland during the non-breeding period. Barn owl breeding and non-breeding home-range size were similar, but there was a small shift in the location of home-ranges which was more pronounced in females than males. The changes in prey availability led to a mainly grassland-oriented habitat selection during the non-breeding period. Further, our results showed the importance of biodiversity promotion areas and undisturbed field margins within the intensively managed agricultural landscape. Conclusions: We showed that differences in prey availability among habitat types between the breeding and the non-breeding period can lead to changes in habitat preference. Given these results we demonstrate the importance to maintain and enhance the structural diversity within the intensive agricultural landscape, to effectively conserve birds of prey specialised on small mammals.

Life-history theory predicts that parents should balance their limited resources to maximize lifetime fitness, limiting their investment in current reproduction when the fitness value of current progeny is lower than that gained by producing offspring in the future. Here, we examined whether male barn owls (Tyto alba) breeding in low-quality habitats increased their parental effort to successfully complete offspring rearing or limited their investment by paying a fitness cost while saving energy for the future. We equipped 128 males with GPS devices between 2016 and 2020 to collect information on home range size, habitat composition, food provisioning rate to the brood and nightly distances covered. We also recorded nestlings' growth and survival, as well as males' body mass variation and future reproductive success. Males living in lower-quality habitats exploited bigger home ranges compared to individuals whose nests were settled in prey-rich habitats. They fed their brood less frequently, while covering longer nightly distance, resulting in a slower growth of late-hatched nestlings and ultimately in a lower fledging success. As males did not differ in body mass variation or future reproductive success our findings suggest that males hunting in home ranges with less prey-rich structures do not jeopardize future reproduction by investing disproportionately larger resources to compensate for their current low home range quality.

Aim Insular populations face different conditions than those living on continents, thus, resulting in the evolution of typical insular phenotypes, like smaller body sizes or reduced colourations. However, the generality of the so-called "island rule" has been questioned, and intraspecific analyses on the effects of insularity on cosmopolitan species are lacking. Here, we tested the predictions of the island rule in the cosmopolitan common barn owl group. Location World. Taxon Barn owl species complex. Methods We compared wing and bill length, as well as melanin-based plumage traits, between thousands of insular and continental barn owls living in the Afro-Palearctic region (Tyto alba), in the Americas (Tyto furcata) and in Australasia (Tyto javanica). We also tested whether the difference between insular and continental populations in these phenotypic traits varies among islands/archipelagos of different size and isolation. Results In all the regions, we found differences between insular and continental owls in all the traits but bill length, with insular populations convergently evolving shorter wings and paler colourations. In addition, the difference in wing size between insular and continental populations is particularly marked on small and remote island systems, while melanin-based traits are less expressed especially on large islands. Main conclusions We thus provide unprecedented evidence that insular conditions drive predictable phenotypic variations, even at the intraspecific level in different biogeographic regions, possibly promoting speciation events. In addition, our results also indicate that selective advantages of a given colouration can arise as the by-product of positive selection on individuals displaying phenotypic traits which can favour island colonization and are genetically linked to melanization.

The eco‐geographical Bergmann's rule predicts that animals have smaller body size in warmer regions than in cold environments because of thermoregulatory reasons. Although this rule has been widely investigated, intraspecific analyses on cosmopolitan taxa are rare. We examined whether geographical variation in wing length, a proxy of body size, shows a Bergmannian pattern and can be explained by three mechanisms known to affect animal body size (heat conservation, resource availability and starvation resistance) in seven species of nocturnal raptors of the genus Tyto.

Predator–prey interactions are amongst the strongest selective forces that promote the evolution of local phenotypes in both predators and prey. However, intraspecific spatial covariation in phenotypic traits between predators and prey has been rarely investigated, especially at a large geographic scale. Here, we studied the covariation between prey composition and some phenotypic traits, such as wing length, bill length and plumage colour, of a widely‐distributed nocturnal predator, the western barn owl Tyto alba. By using 3100 specimens collected across its entire range of distribution, spanning from Europe to Middle East and Africa, we showed that wing length positively covaries with prey size, but not with taxonomic composition. This finding suggests that larger prey might have selected for larger body size and/or that larger individuals might be more selective in hunting large prey. In addition, we also found that paler‐plumaged populations generally hunt larger prey. Paler barn owls might be thus better specialized in capturing averagely larger prey and/or mainly hunt in habitats where larger prey are more abundant. In addition, considering that paler individuals are generally larger than brownish ones, it is possible that paler plumage colour might have evolved as a by‐product of selection towards a large body size, which in turn have emerged in response to prey size composition. However, irrespectively of the direction of causality and the phenotypic target of selection, we showed that predator–prey interactions can affect spatial phenotypic variation by promoting the evolution of local adaptations.

Background The intensification of agricultural practices over the twentieth century led to a cascade of detrimental effects on ecosystems. In Europe, agri-environment schemes (AES) have since been adopted to counter the decrease in farmland biodiversity, with the promotion of extensive habitats such as wildflower strips and extensive meadows. Despite having beneficial effects documented for multiple taxa, their profitability for top farmland predators, like raptors, is still debated. Such species with high movement capabilities have large home ranges with fluctuation in habitat use depending on specific needs. Methods Using GPS devices, we recorded positions for 134 barn owls ( Tyto alba ) breeding in Swiss farmland and distinguished three main behavioural modes with the Expectation-Maximization binary Clustering (EMbC) method: perching, hunting and commuting. We described barn owl habitat use at different levels during the breeding season by combining step and path selection functions. In particular, we examined the association between behavioural modes and habitat type, with special consideration for AES habitat structures. Results Despite a preference for the most common habitats at the home range level, behaviour-specific analyses revealed more specific habitat use depending on the behavioural mode. During the day, owls roosted almost exclusively in buildings, while pastures, meadows and forest edges were preferred as nocturnal perching sites. For hunting, barn owls preferentially used AES habitat structures though without neglecting more intensively exploited areas. For commuting, open habitats were preferred over wooded areas. Conclusions The behaviour-specific approach used here provides a comprehensive breakdown of barn owl habitat selection during the reproductive season and highlights its importance to understand complex animal habitat preferences. Our results highlight the importance of AES in restoring and maintaining functional trophic chains in farmland.

Bird nests are specialized habitats because of their particular composition including nest detritus and bird droppings. In consequence, they attract a specialized arthropod community considered as nidicolous, which includes species only found in bird nests (strictly nidicolous) or sometimes found in bird nests (facultatively nidicolous). Because the factors influencing the entomofauna in bird nests are poorly understood, in autumn 2019, we collected nest material in 86 Barn Owl (Tyto alba) nest boxes. We investigated whether the invertebrate species richness was related to Barn Owl nest box occupancy, the density of available nest boxes and the landscape structure. We found 3,321 nidicolous beetle specimens belonging to 24 species. Species richness of strictly nidicolous beetles was 2.7 times higher in nest boxes occupied by a family of Barn Owls the previous spring compared to unoccupied nest boxes. It was also higher in sites that were more often occupied by Barn Owls in the five previous years and in areas surrounded by a higher proportion of crop fields. For facultatively nidicolous beetles, the density of Barn Owl nest boxes enhanced the species richness. In conclusion, our study suggests that the strictly nidicolous beetles benefit from occupied nest boxes of Barn Owls, whereas facultatively nidicolous beetles look for nest boxes independently of whether Barn Owls occupy them. Our study highlights the importance of bird nests for a suite of invertebrates.

The investigation of biogeographical patterns in the diet of widely distributed predators is essential to understand their ecology, life history traits and local adaptations. However, it is particularly challenging because of their wide distribution, broad trophic spectra and high ecological plasticity. Here, we described patterns of trophic ecology in a cosmopolitan nocturnal raptor, the common barn owl group, from a biogeographical perspective. We then compared variation in diet between barn owls living in the Americas (T. furcata), and those inhabiting Europe, Middle‐East and Africa (T. alba), thus hunting on different assemblages of prey types.

Aim Avian beak morphology is a good example of how anatomical structures have evolved in response to different selective pressures, such as diet and vocalizations, but also thermoregulation. The last of these functions was neglected until recently, but convincing evidence has been provided regarding the capacity of birds to regulate heat dissipation through their highly vascularized bills. According to this adaptive function and coherently with the ecogeographical "Allen's rule", which predicts smaller body appendages in colder climates, large beaks should be favoured in warm environments. Here, we tested this prediction in the cosmopolitan common barn owl group. Location World. Time period 1809-2017. Major taxa studied Tyto alba species complex. Methods We analysed the variation in bill length relative to body size according to temperature, latitude and elevation in 7,619 barn owls. The specimens were collected by 140 museums and represent three distinct evolutionary lineages that occur in geographically separated regions and cover the entire distributional range of the species complex: the Afro-Palaearctic Tyto alba, the Australasian Tyto javanica and the American Tyto furcata. Results In the three lineages, the bill becomes larger with increasing temperature. This convergent pattern of evolution of smaller bills in colder climates is associated with a latitudinal variation in temperature, because small-billed individuals occurred at higher latitudes than conspecifics living closer to the Equator. Moreover, in T. furcata, large-billed birds mostly occurred at lower elevations closer to the Equator, with bill length decreasing progressively with concomitant increase in latitude and elevation. Discussion These findings provide evidence for the repeated evolution of bill size on a global scale that is compatible with Allen's rule. These results suggest a role of the bill as a potential heat-exchange surface in nocturnal raptors, which are not directly exposed to solar radiation and whose bill shape evolved primarily to hunt and consume animal prey.

Animal tracking data are being collected more frequently, in greater detail, and on smaller taxa than ever before. These data hold the promise to increase the relevance of animal movement for understanding ecological processes, but this potential will only be fully realized if their accompanying location error is properly addressed. Historically, coarsely-sampled movement data have proved invaluable for understanding large scale processes (e.g., home range, habitat selection, etc.), but modern fine-scale data promise to unlock far more ecological information. While location error can often be ignored in coarsely sampled data, fine-scale data require much more care, and tools to do this have been lacking. Current approaches to dealing with location error largely fall into two categories—either discarding the least accurate location estimates prior to analysis or simultaneously fitting movement and error parameters in a hidden-state model. Unfortunately, both of these approaches have serious flaws. Here, we provide a general framework to account for location error in the analysis of animal tracking data, so that their potential can be unlocked. We apply our error-model-selection framework to 190 GPS, cellular, and acoustic devices representing 27 models from 14 manufacturers. Collectively, these devices are used to track a wide range of animal species comprising birds, fish, reptiles, and mammals of different sizes and with different behaviors, in urban, suburban, and wild settings. Then, using empirical data on tracked individuals from multiple species, we provide an overview of modern, error-informed movement analyses, including continuous-time path reconstruction, home-range distribution, home-range overlap, speed and distance estimation. Adding to these techniques, we introduce new error-informed estimators for outlier detection and autocorrelation visualization. We furthermore demonstrate how error-informed analyses on calibrated tracking data can be necessary to ensure that estimates are accurate and insensitive to location error, and allow researchers to use all of their data. Because error-induced biases depend on so many factors—sampling schedule, movement characteristics, tracking device, habitat, etc.—differential bias can easily confound biological inference and lead researchers to draw false conclusions.