摘要: Wetland waterbirds serve as key ecological indicators for assessing habitat quality and biodiversity.Accurate identification of waterbird species is a cornerstone of long-term ecological monitoring.The resulting data are critical for assessing wetland ecosystem health and biodiversity.However,prevailing recognition approaches often prioritize detection accuracy at the expense of computational efficiency.They are also hindered by complex background heterogeneity and interspecies visual similarity.These limitations hinder the scalability and practical deployment of such methods for on-site ecological monitoring within wetland ecosystems.To address these challenges,this study proposes an optimized end-to-end framework,ShuffleNetV2-iRMB-ShapeIoU-YOLO(SISYOLO),designed for robust recognition of wetland waterbirds in complex environments.Specifically,the proposed framework integrates ShuffleNetV2 with inverted Residual Mobile Blocks(iRMB) to improve computational efficiency while maintaining robust feature representation.This design further enables deployment on resource-constrained mobile and embedded platforms.Additionally,ShapeIoU,a refined bounding box similarity metric,is introduced to jointly optimize overlap and shape consistency,effectively mitigating misclassification among visually similar species.Experimental results on the IC-Beijing dataset show that SIS-YOLO achieves 91.1% precision and 79.1% mAP@0.5:0.95 with only 2.9 million parameters.Compared with the lightweight baseline YOLOv8n,it improves precision by 2% and mAP@0.5:0.95 by 1.2%,while requiring fewer parameters and offering higher computational efficiency.

摘要: Bird monitoring and protection are essential for maintaining biodiversity,and fine-grained bird classification has become a key focus in this field.Audio-visual modalities provide critical cues for this task,but robust feature extraction and efficient fusion remain major challenges.We introduce a multi-stage fine-grained audiovisual fusion network(MSFG-AVFNet) for fine-grained bird species classification,which addresses these challenges through two key components:(1) the audiovisual feature extraction module,which adopts a multi-stage finetuning strategy to provide high-quality unimodal features,laying a solid foundation for modality fusion;(2) the audiovisual feature fusion module,which combines a max pooling aggregation strategy with a novel audiovisual loss function to achieve effective and robust feature fusion.Experiments were conducted on the self-built AVB81and the publicly available SSW60 datasets,which contain data from 81 and 60 bird species,respectively.Comprehensive experiments demonstrate that our approach achieves notable performance gains,outperforming existing state-of-the-art methods.These results highlight its effectiveness in leveraging audiovisual modalities for fine-grained bird classification and its potential to support ecological monitoring and biodiversity research.

摘要: Highly pathogenic avian influenza(HPAI) H5 viruses have caused widespread mortality in wild birds and poultry,with increasing spillover risk into mammals.The recently dominant clade 2.3.4.4b has produced multiple epidemic waves,first driven by H5N8 and more recently by H5N1,which has spread more rapidly,infected a broader host range,and caused higher mortality.While earlier studies identified consistent roles of waterbird community composition in shaping HPAI outbreaks,it remains unclear whether these factors also apply to the currently circulating H5N1.We analyzed HPAI H5N1 outbreaks in European wild birds during the 2021/22epidemic,examining the influence of waterbird communities and environmental variables,and compared these patterns with earlier epidemics,including H5N1 in 2005/06 and H5N8 in 2016/17 and 2020/21.Our results showed that waterbird abundance,species richness,and the abundance of key species were positively associated with disease occurrence,whereas phylogenetic diversity was negatively associated,suggesting greater interspecific transmission among closely related hosts.Models trained on earlier epidemics accurately predicted the H5N1 occurrence in 2021/22.These findings demonstrate consistent effects of waterbird community composition across multiple epidemics and highlight their values as predictors of HPAI risk.Integrating community metrics into surveillance and early-warning systems can strengthen our capacity to anticipate future outbreaks across clades and subtypes.

摘要: Avian wings are central to their remarkable flight ability and diverse life history strategies,including behaviors such as fighting and mating.These multifaceted functions are intricately tied to wing shape,which varies significantly across species because of the complex interplay of evolutionary and ecological pressures.Many indices have been developed to quantify wing characteristics to facilitate the study and comparison of avian wing morphology across species.This study provides a comprehensive overview of existing quantitative methods for analyzing avian wing shapes.We then constructed a new quantification framework through the beta distribution,which can generate indices reflecting the shape of avian wings(center,dispersion,skewness,and kurtosis).Next,we used the flight feathers of 613 bird species to perform different quantitative analyses and explore the relationships between various wing shape quantification methods and life history traits,which serve as proxies for the selective forces shaping wing morphology.We find that the wing shape indices are more strongly associated with ecological variables than with morphological variables,especially for migration,habitat and territoriality.This research guides the selection of appropriate methods for wing shape analysis,contributing to a deeper understanding of avian morphology and its evolutionary drivers.

摘要: Sexual dichromatism represents a major form of phenotypic differentiation between the sexes in birds,and its evolution is likely shaped by the interplay between sexual and natural selection.The genus Ficedula,widely distributed across Eurasia,exhibits pronounced interspecific variation in both sexual dichromatism and migratory behavior,making it an ideal study system for investigating the evolutionary patterns and drivers of avian sexual dichromatism.In this study,we conducted a phylogenetic comparative analysis of plumage complexity and sexual dichromatism across 32 Ficedula species.We further explored how life-history traits influence the evolution of sexual dichromatism.Our results reveal a strong positive correlation between male plumage complexity and the degree of sexual dichromatism,with males evolving plumage complexity at significantly faster rates than females.Migratory species exhibit significantly higher levels of dichromatism.Furthermore,compared to monochromatic species,sexually dichromatic species are characterized by higher latitudinal occurrence,broader geographic distributions,and greater flight capacity.These findings demonstrated how sexual and natural selection jointly drive evolution of sexual dichromatism in Ficedula within phylogenetic constraints,advancing our understanding of the evolutionary drivers of avian sexual dichromatism.

摘要: Animal behavioral studies are often combined with research concerning cognitive abilities.Larger brains usually mean more complex neural networks and advanced cognitive functions.By measuring the brain size of different individual animals,we can explore differences in behavioral complexity between populations or species.However,obtaining accurate measurements of brain size is challenging both in field and laboratory environments,especially for rare and endangered species.Therefore,there is an urgent need to develop reliable methods for performing cranial brain mass.This study tests which external structures of the avian head can most accurately predict brain size.We selected five bird species from four orders,categorized external head measures into three types of parameters(direct,calculated and composite measurements),and analyzed these in relation to brain mass.The results showed that while head size can partially explain brain mass,the parameters of head height x head width were the most accurate predictors of brain mass in birds(90.4%).In addition,the positive correlation between endocranial volume and brain mass once again confirmed that avian endocranial volume can,to a certain extent,serve as a valid proxy for brain mass.Our study demonstrates that in the future we can more conveniently perform non-invasive measurements to better understand the relationship between bird brain size and behavior,ecology,and evolution.

摘要: Predator dummies are usually used to explore the impact of predator features on the anti-predator behavior of birds.Previous studies have shown that the morphology and behavior of aerial predators can signal different threat levels to birds.However,whether subtle changes in ground predator dummies cause changes in the nest defense behavior of parent birds is unclear.In this study,we aimed to investigate whether Japanese Tits(Parus minor) exhibit different nest defense behaviors in response to experimentally manipulated variations in the appearance,posture,and size of virtual snake proxies(common nest predators).During the incubation period,we observed the nest defense behaviors of the parent tits against taxidermized Siberian Ratsnakes(Elaphe schrenckii) with varied characteristics and rubber-made model snakes.The tits exhibited more intense responses to taxidermized large(body length about 120 cm) coiled ratsnakes than to large coiled model snakes.They exhibited weaker responses to taxidermized small(body length about 20 cm) coiled ratsnakes than to taxidermized small sinusoidal ratsnakes.In addition,they exhibited more intense responses to taxidermized large coiled ratsnakes than to taxidermized small coiled ratsnakes,and more intense responses to taxidermized small sinusoidal ratsnakes than to large model snakes.However,there was no difference in the response of tits to taxidermized small sinusoidal ratsnakes and taxidermized large coiled ratsnakes,or to taxidermized small coiled ratsnakes and model snakes.Thus,the presence of scales,a sinusoidal posture,and a large body size of snake dummies can induce more intense behavioral responses in Japanese Tits.We suggested that Japanese Tits can discriminate subtle differences in ground predator dummies of nests and exhibit different nest defense behaviors.

摘要: Urbanization has significantly altered the habitat structure and behavioral patterns of animals.In urban environments with frequent human disturbances,animals may undergo adaptive adjustments in their escape behaviors.This study focuses on Eurasian Tree Sparrows(Passer montanus) from five cities across different latitudes in China,comparing their flight initiation distance(FID) in urban and rural areas to assess the impact of urbanization on their escape behavior and the trend of ecological homogenization.The results confirm the established pattern at the geographic level:a reduction of FID in urban habitats and a decrease in FID with increasing latitude.That is,northern populations of the Eurasian Tree Sparrow in China are bolder than the southern populations.In addition,FID is positively correlated with flock size,with rural flocks exhibiting more pronounced group behavior(observed flocking frequency for urban and rural is 28.74% vs.40.7%,flock size variance is 26.90 vs.55.63).Despite the differences between northern and southern latitudes,the variability of FID in urban individuals consistently remains lower than that in rural areas,supporting the trend of reduced variability in escape behavior among birds in urban environments.Driven by urbanization,the escape behavior of Eurasian Tree Sparrows tends toward ecological homogenization,meaning that behavioral differences between urban areas in different cities are diminishing.This trend may obscure the behavioral variability brought about by latitude gradients,indicating that urbanization not only shapes the behavioral adaptations of birds but also potentially weakens their behavioral diversity.

摘要: Recognition of heterospecific mobbing calls can occur through both innate and learned mechanisms,with the former often explained by two main hypotheses:the acoustic similarity hypothesis,which emphasizes shared acoustic features,and the phylogenetic conservatism hypothesis,which posits that closely related species may share innate decoding templates.However,it remains unclear whether phylogenetic relatedness alone can drive the recognition of unfamiliar mobbing calls,a question with important implications for understanding the evolution of interspecific communication and anti-predator strategies.We examined the recognition of unfamiliar mobbing calls in Masked Laughingthrushes(Pterorhinus perspicillatus) using playback experiments with three allopatric species' mobbing calls of Leiothrichidae family.Results revealed two key findings:(1) Masked Laughingthrushes exhibited mobbing responses to unfamiliar mobbing calls,though at significantly lower intensity compared to conspecific playbacks.(2) Phylogenetic relatedness significantly predicted mobbing intensity,independent of overall acoustic similarity.These findings improve our understanding of how birds like Masked Laughingthrush instinctively recognize mobbing calls from other species.We show phylogenetic relatedness rather than overall acoustic similarity may be a key to this innate ability.Species that share a common ancestor may possess similar built-in neural systems for decoding alarm signals.We suggest that future research needs to combine neurobiological techniques to determine how inherited biases and feature decoding system together guide variable bird communities to perceive heterospecific mobbing calls.

摘要: Numerous hypotheses predict associations between phenotype-associated breeder traits and reproductive success.In secondary cavity-nesting passerine birds,which have been investigated most,up to more than 90parental characteristics have been linked to at least one field measure of breeding performance.However,within study populations,different parental traits,such as clutch size,first-egg date,egg size,nest architecture,plumage colour,adult morphometry,or song performance,are often weakly correlated across female and/or male breeders.Furthermore,many of these studies have been conducted outside the theoretical framework of the'Individual Optimisation Hypothesis' of clutch size(IOH).IOH predicts that:(i) females with larger clutches will have larger broods at hatching and fledging compared to those with smaller clutches;and(ii) clutch size,which is adaptively adjusted to the parents' ability to rear nestlings,should always maximize the percentage of eggs producing fledglings so that variation in clutch size becomes disconnected from variation in breeding success.In this paper,we present the first detailed review of implications of IOH for parental characters other than clutch size.Our review covered 188 non-experimental studies and 1074 statistical results that examined how parental traits influence breeding success in Western Palearctic Great Tits(Parus major),Blue Tits(Cyanistes spp.),and flycatchers(Ficedula spp.).Clutch size explained one third of the variation in brood size at hatching and fledging within study populations.However,most parental characteristics associated weakly with the number of hatchlings or fledglings,likely because they did not correlate with clutch size.Overall,parental traits were poorly correlated with the proportion of hatchlings and fledglings per egg.We discuss why intraspecific variation in phenotype-associated breeder traits is often disconnected from interindividual differences in breeding success,and highlight the importance of underexplored research problems in avian breeding biology.