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Keywords: distribution; ecological niche; Montifringilla nivalis; mountains; seasonality; snowfinch EN distribution ecological niche Montifringilla nivalis mountains seasonality snowfinch 1 5 5 10/07/22 20220901 NES 220901 Linking organism distribution to climate is key to understanding factors determining species occurrence and evaluating the potential impacts of ongoing climate change. Insufficient considerations of seasonality, data selection and validation lead to biased species-climate relationships in mountain birds However, we are convinced that the reason for such a finding is not an effective niche expansion in the species, but a question of methods - the inclusion of non-representative occurrence records in the analyses of the species' thermal niche -, neglecting crucial facts about the species' ecology. According to the authors, such a wider niche should be related to a "dramatic niche evolution event", leading to a niche expansion dated perhaps 2.6 mya ago, which allowed this species to occupy warmer areas in the western Palearctic, such as southern Europe. [Extracted from the article]

The article discusses a study which investigated the signaling role played by achromatic plumage patches and examined the patterns and characteristics of the brightness of Eurasian eagle-owl's white feather patches for adult and young birds. The study collected blood from breeders and young birds and measured the brightness of their white plumage. Results revealed that the total reflectance of the white feathers in young birds differed from that of the white feathers in adult owls and the brightness was distinct between the sexes only in adults.

The article presents a study on the breeding output and quality of chicks in the first and replacement clutches in the Eagle Owl Bubo bubo. The researchers collected chick measurements and blood samples when nestlings were about 30 to 35 days old. They also subjected the dependent variable nesting attempt to a generalized linear mixed model (GLMM) analysis assuming binomial error structure. They found that replacement clutches are important on the fecundity of big long-lived species like the Eagle Owl.

Aim: High‐elevation specialist species are threatened by climate change and habitat loss, and their distributions are becoming increasingly reduced and fragmented. In such a context, dispersal ability is crucial to maintain gene flow among patches of suitable habitat. However, information about dispersal is often lacking for these species, especially for those taxa that are usually considered as good dispersers such as birds. We adopted a landscape genomics approach to investigate dispersal in a climate‐sensitive high‐elevation specialist bird. Our aims were to assess the levels of gene flow within a wide mountain area, and to assess the effects of geographic distance and landscape characteristics on dispersal, by testing the isolation by distance (IBD) hypothesis against the isolation by resistance (IBR) hypothesis. Location: European Alps. Taxon: Montifringilla nivalis. Methods: We sampled individuals from several breeding areas and obtained single nucleotide polymorphism (SNP) data by ddRAD sequencing. We then calculated site‐ and individual level genetic distances and individual inbreeding coefficients. To test IBD versus IBR, we related genetic distances to both geographic distances and different measures of landscape resistance by using maximum likelihood population effects models. Results: Gene flow among breeding areas was partly restricted, and we found support for IBD, indicating that geographic distance limits snowfinch dispersal. Spatial patterns of genetic distances suggested that philopatry strongly contributed to determine the observed IBD. High inbreeding coefficients in several individuals indicated frequent mating among relatives. Main Conclusions: Restricted dispersal and frequent inbreeding within 'sky island' systems can also occur in highly mobile species, because their potential ability to cover very large distances can be counteracted by high philopatry levels that are likely related to high dispersal costs. IBD and philopatry will increasingly hinder snowfinch dispersal among suitable areas within the future more restricted and fragmented breeding range, increasing the risks of local extinctions. [ABSTRACT FROM AUTHOR]

In endotherm animals, several traits are related to climate. For example, Bergmann's rule predicts a decrease in body size within species and across closely related species with increasing temperature, whereas Gloger's rule states that birds and mammals should be darker in humid and warm environments compared to colder and drier areas. However, it is still not clear whether ecotypic responses to variation in the local environment can also apply to morphological and colouration changes through time in response to climate change. We present a 100-year-long time series on morphological and melanin-based colours of snowfinch (325 Montifringilla, 92 Pyrgilauda and 30 Onychostruthus) museum specimens. Here we show that the tarsus length of the species has decreased and the saturation of the melanin-based colour has increased, which was correlated with the increase of temperature and precipitations. As ecotypic variations are tightly linked to individual behavioural and physiological responses to environmental variations, differently sized and coloured individuals are expected to be differently penalized by global changes. This study opens the pertinent question about whether ecotypic responses can enhance population persistence in the context of global change. [ABSTRACT FROM AUTHOR]

Microhabitat utilisation holds a pivotal role in shaping a species' ecological dynamics and stands as a crucial concern for effective conservation strategies. Despite its critical importance, microhabitat use has frequently been addressed as static, centering on microhabitat preference. Yet, a dynamic microhabitat use that allows individuals to adjust to fine-scale spatio-temporal prey fluctuations, becomes imperative for species thriving in challenging environments. High-elevation ecosystems, marked by brief growing seasons and distinct abiotic processes like snowmelt, winds, and solar radiation, feature an ephemeral distribution of key resources. To better understand species' strategies in coping with these rapidly changing environments, we delved into the foraging behaviour of the white-winged snowfinch Montifringilla nivalis, an emblematic high-elevation passerine. Through studying microhabitat preferences during breeding while assessing invertebrate prey availability, we unveiled a highly flexible microhabitat use process. Notably, snowfinches exhibited specific microhabitat preferences, favoring grass and melting snow margins, while also responding to local invertebrate availability. This behaviour was particularly evident in snow-associated microhabitats and less pronounced amid tall grass. Moreover, our investigation underscored snowfinches' fidelity to foraging sites, with over half located within 10 m of previous spots. This consistent use prevailed in snow-associated microhabitats and high-prey-density zones. These findings provide the first evidence of dynamic microhabitat use in high-elevation ecosystems and offer further insights into the crucial role of microhabitats for climate-sensitive species. They call for multi-faceted conservation strategies that go beyond identifying and protecting optimal thermal buffering areas in the face of global warming to also encompass locations hosting high invertebrate densities. [ABSTRACT FROM AUTHOR]

Many animals make behavioural changes to cope with winter conditions, being gregariousness a common strategy. Several factors have been invoked to explain why gregariousness may evolve during winter, with individuals coming together and separating as they trade off the different costs and benefits of living in groups. These trade-offs may, however, change over space and time as a response to varying environmental conditions. Despite its importance, little is known about the factors triggering gregarious behaviour during winter and its change in response to variation in weather conditions is poorly documented. Here, we aimed at quantifying largescale patterns in wintering associations over 23 years of the white-winged snowfinch Montifringilla nivalis nivalis. We found that individuals gather in larger groups at sites with harsh wintering conditions. Individuals at colder sites reunite later and separate earlier in the season than at warmer sites. However, the magnitude and phenology of wintering associations are ruled by changes in weather conditions. When the temperature increased or the levels of precipitation decreased, group size substantially decreased, and individuals stayed united in groups for a shorter time. These results shed light on factors driving gregariousness and points to shifting winter climate as an important factor influencing this behaviour. [ABSTRACT FROM AUTHOR]

Many countries promote wildlife observation as part of ecotourism offerings. The brown bear Ursus arctos is among the most targeted species for ecotourism in North America and Europe, making it an ideal candidate to examine the consequences of wildlife viewing upon the species. As bear viewing often occurs in sensitive places where bears congregate for mating, rearing young and/or feeding, it is important to evaluate potential positive and negative effects of different viewing practices. Here we reviewed available information on bear viewing practices and their effects on bears, people and ecosystems. Behavioural, physiological and ecological aspects related to bears are reviewed from three different perspectives: ecotourism consequences for bears, direct bear-human interactions and social impacts of bear ecotourism. Because bear viewing can have positive and negative impacts on both bear populations and bear-human interactions, it is important to carefully evaluate every practice associated with bear viewing at a local scale. Because bear populations around the world have diverse population statuses and different management regimes, successful procedures and rules effective in one place do not guarantee that they will be adequate elsewhere. Effective management of bear viewing practices requires a better understanding of the consequences for bears, the mechanisms behind observed bear reactions to humans, and the results of bear habituation. Because inappropriate bear viewing practices can lead to processes such as food-conditioning and habituation, which can have serious consequences for both people and bears, regulations on bear ecotourism are urgently needed to minimize unintended consequences of bear viewing practices. [ABSTRACT FROM AUTHOR]

The rather limited human ability to understand animal vision and visual signalling has frequently clouded our expectations concerning the visual abilities of other animals. But there are multiple reasons to suspect that visual signalling is more widely employed by animals than previously thought. Because visibility of visual marks depends on the background in which they are seen, species spending most of their time living in dark conditions (e.g., in forests and/or having crepuscular and nocturnal habits) may rely on bright signals to enhance visual display. Here, as a result of experimental manipulations, we present, for the first time ever, evidence supporting the use of a new channel of intraspecific communication by a mammal species, i.e., brown bear Ursus arctos adult males relying on visual marks during mating. Bear reactions to our manipulation suggest that visual signalling could represent a widely overlooked mechanism in mammal communication, which may be more broadly employed than was previously thought. [ABSTRACT FROM AUTHOR]

Reliable methods to measure stress-related glucocorticoid responses in free-ranging animals are important for wildlife management and conservation. Such methods are also paramount for our ability to improve our knowledge of the ecological consequences of physiological processes. The brownbear (Ursus arctos) is a large carnivore of ecological and cultural importance and is important for management. Here, we provide a physiological validation for an enzyme immunoassay (EIA) to quantify glucocorticoid metabolites in brown bear feces. We also provide an evaluationof the effects of sample exposure to ambient temperature on measured fecal glucocorticoid metabolite (fGCM) concentrations. We evaluated three EIA systems: a cortisol assay, an 11- oxoetiocholanolone assay, and an 11b-hydroxyetiocholanolone assay. Of these, the cortisol assay provided the best discrimination between peak fGCM concentrations detected 1–4 d after injections of synthetic adrenocorticotrophic hormone and preinjection baseline concentrations in four individual brown bears. The time of exposure to ambient temperature had substantial but variable effects on measured fGCM concentrations, including variation both between samples from the same individual and among samples from different bears. We propose that the validated EIA system for measuring fGCM concentrations in the brown bear could be a useful noninvasive method to monitor stress in this species. However, we highlight that this method requires that fecal samples be frozen immediately after defecation, which could be a limitation in many field situations. [ABSTRACT FROM AUTHOR]