Migratory species are vulnerable to habitat loss, especially migratory birds that rely on multiple stopover sites during migration. According to conventional understanding, migratory birds typically show reduced behavioral variability as they age, with their migration routes becoming increasingly fixed through experience, which may make them even more vulnerable to habitat loss along their flyway. Indeed, in the East Asian-Australasian Flyway (EAAF), most waterbird populations have rapidly declined due to habitat loss and land use changes. However, some migratory species like the Pied Avocet Recurvirostra avosetta have maintained or even increased their populations. We investigated whether this success might be linked to age-related patterns in migration behavior. Using satellite tracking technology, we monitored the movement behaviors of 48 adult and 20 juvenile Pied Avocets in eastern China from 2021 to 2024. Contrary to expectations, adults exhibited greater movement variability than juveniles. In the first two years of life, Pied Avocets performed relatively limited movements, adopting conservative migration strategies, which may reduce mortality risks. In contrast, experienced adults showed greater variability in their movement patterns. Some migrated to more southerly wintering grounds or more northerly breeding sites, and occasionally pioneered entirely new flight paths. Compared to juveniles, adult birds also showed larger home ranges during the pre-migration period and greater within-season movements during the non-migration period. This age-related increase in ranging behavior and movement variability may contribute to their population resilience in rapidly changing environments. Our findings suggest that the combination of risk-averse strategies in young birds and diverse movement strategies within adult populations, ranging from conservative to exploratory individuals, might represent an important adaptation mechanism for long-lived species facing environmental change.

Background Rapid advances in animal tracking technologies have generated unprecedented volumes of high-resolution movement data. However, prevailing trajectory-based (Lagrangian) analytical approaches exhibit poor transferability across divergent sampling regimes and struggle to distinguish behaviors with overlapping movement signatures, leaving spatially defined ecological information underexplored. Methods We present an integrated, systematic framework that applies Eulerian, place-based spatiotemporal point pattern analysis to avian tracking data, offering a complementary perspective to traditional Lagrangian, path-based movement approaches. Using five species case studies of migratory shorebirds, waterfowl, and raptors, we integrated spatial statistical methods (e.g., Behaviorally-Anchored Local Moran, DBSCAN clustering) with geoprocessing tools in ArcGIS Pro and R (movepp package). This workflow enables movement states classification, delineation of breeding, stopover, and wintering habitats, and detection of fine-scale behaviors such as foraging, roosting and nesting, with activity pattern inferred from diel timing and habitat associations. Results The framework successfully identified migration phases and resolved movement dynamics at annual, seasonal, and diel scales. Derived point pattern metrics enabled the quantification of site fidelity and nest-site fidelity, as well as the characterization of circadian rhythms in habitat use. The detection of breeding behavior achieved high spatial and temporal precision, comparable to conventional analytical methods. Furthermore, this framework provides standardized and transferable indicators applicable across diverse species. Conclusions By bringing the toolkit of spatial point-pattern analysis to movement data, this framework provides innovative methodologies and practical guidelines to extract robust ecological insights from tracking point data in a fully reproducible and transferable manner. It improves comparative analyses of migratory strategies and supports targeted conservation planning by identifying multi-scale critical habitats and behavioral patterns across scales. Complementing conventional trajectory-based analytical paradigms, this approach broadens the dimensionality of behavioral interpretation from animal movement data.

Penduline tits (genus Remiz) are small passerines distributed across Europe, Central and East Asia, and North Africa, renowned for their elaborate nests and unusually diverse mating systems. However, the taxonomy and evolutionary relationships within this genus have remained contentious due to overlapping breeding distributions and extensive hybridization. Using broad-range geographic sampling and whole-genome sequencing, here we report the phylogenetic relationships within this genus. Our results from maximum likelihood trees, species trees, population structure, and PCA analyses consistently identify four distinct, well-supported monophyletic clades. Based on these robust results, we support dividing Remiz into four species: the Eurasian Penduline Tit (R. pendulinus), Black-headed Penduline Tit (R. macronyx), White-crowned Penduline Tit (R. coronatus), and Chinese Penduline Tit (R. consobrinus). Among these species, R. consobrinus diverged earlier from other species, followed by R. coronatus, and then, R. pendulinus and R. macronyx. R. pendulinus and R. macronyx showed shallow genetic differentiation with recent divergence (∼87,000 years ago) and ongoing gene flow. Our findings demonstrate the effectiveness of phylogenomic approaches in resolving taxonomic ambiguities and provide a robust evolutionary framework for tracing the diversification of life history traits, particularly nest structures and mating systems, across the genus.

One of the most effective strategies for avian hosts to defend against brood parasitism is to reject the parasitic egg from the focal nest. However, substantial inter-individual variability in egg-rejection behavior remains unexplained. A critical prerequisite for egg ejection is the recognition of the parasitic egg. Hosts may improve recognition accuracy by increasing inspection frequency and duration, thereby facilitating comparisons between the foreign egg and their own eggs. In this study, we investigated the relationship between egg inspection and egg-rejection behavior in the Daurian redstarts Phoenicurus auroreus, a common host of the common cuckoo Cuculus canorus. Following the introduction of a model cuckoo egg, redstart females increased both the frequency and duration of egg inspection. Moreover, individuals that inspected the parasitic egg more frequently and for longer were more likely to recognize it. However, inspection behavior was not associated with subsequent egg ejection. Therefore, our results demonstrate that egg inspection enhances recognition of the parasitic egg but does not directly translate into ejection decisions.

Species with diverse parental care systems exhibit flexibility in response to environmental changes. Such changes can influence parental care decisions by altering the trade-offs between current and future reproduction. While previous studies have revealed correlations between specific social and ecological factors and parental care systems, the joint effects of multiple factors could be complex and may result in different outcomes within and across populations and between sexes. In this study, we observed parental care systems and their seasonal variations across three geographic populations in a polygamous species, the Chinese penduline tits (Remiz consobrinus), by monitoring breeding events over 8 years. In this species, biparental care, female-only care, male-only care and biparental desertion coexist in one population. To investigate whether and how sex-specific parental care patterns correlate with local conditions, we compared breeding phenology, season length, mating opportunity and reproductive success and their associations with the frequency of parental care patterns observed within and across the populations. We found striking population differences in the parental care system: biparental care predominated in one population, whereas female-only care was more common in the other two. These divergent parental care systems were shaped by sex-specific responses to the interacting local conditions. In all three populations, females synchronised egg-laying and offered males a short but highly successful re-mating window. This resulted in rapidly decreased male mating opportunities due to male collective clutch desertion. Males were more likely to care when re-mating opportunities were low. In contrast, females consistently provided care, regardless of variations in female mating opportunities. Additionally, males deserted clutches more in populations where desertion resulted in no fitness cost to the current broods. We found that desertion costs on brood fitness matter more than achieving a high reproductive reward in driving uniparental care, contrary to the theory that uniparental care only occurs when single parents can raise young efficiently. Our study demonstrates that parental care system variance across populations could result from the combined influences of social and ecological conditions, and their interactions. We highlight the consistency of sex-specific responses to local conditions in parental care.

Bird nest construction is shaped by both avian morphology and ecological context. In this study, we provide the first quantitative descriptions of nest structural parameters and material composition for the White-crowned Penduline Tit (Remiz coronatus) and the Black-headed Penduline Tit (R. macronyx). We also collected nest data for the Chinese Penduline Tit (R. consobrinus), allowing a descriptive comparison of nest architecture and nest materials across penduline tits. By quantifying nest structural parameters, nest mass, and material composition, we documented interspecific and interpopulation variation in several nest traits, including nest width, wall thickness, and corridor length. In the sampled nests, Chinese and White-crowned Penduline Tits used mainly shredded plant stems, plant down, and wool, with mud additionally recorded in the White-crowned Penduline Tit, whereas Black-headed Penduline Tit nests consisted primarily of shredded reed leaves and reed down. Exploratory comparisons further suggested that populations with greater mean body length tended to have larger nest inner diameters, and that species with larger mean beak size tended to use wider nest fibers. Although these comparisons are descriptive only, our study provides new comparative natural history data on nest architecture and material use in penduline tits, laying a foundation for future work on the morphological and ecological drivers of nest construction in this group.

Sexual dichromatism is generally thought to arise from sexual selection favouring elaborately coloured males, as proposed in Darwin's model. Wallace offers an expanded perspective, emphasising that the evolution of cryptic and dim female colouration to evade nest predation significantly contributed to the origin of sexual dichromatism. However, previous studies on the evolutionary forces of sexual dichromatism examining Darwin's and Wallace's models have produced mixed results. Here, we re-examined Wallace's model of female-biased selection using the largest and most ecologically diverse family of landfowl (Phasianidae), known for its wide-ranging distribution and striking colour patterns. Our results demonstrate that the level of sexual dichromatism is negatively correlated with colour complexity in females but not males, and the evolutionary rates of sexual dichromatism are positively correlated with the evolutionary rates of colour complexity in both sexes. Furthermore, we show that female colour complexity is significantly associated with nest exposure, consistent with predation-related ecological constraints on female colour evolution. Together, these findings support Wallace's model by highlighting the importance of nest predation in shaping female colouration, while further suggesting that the evolution of sexual dichromatism reflects the dynamic interplay of natural and sexual selection.

The biological species concept defines species as groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups(Mayr,1942).Reproductive isolation,whether prezygotic or postzygotic,plays a central role in maintaining species boundaries.

Elongated tails are exaggerated ornaments observed in various bird species, and their functional and evolutionary dynamics have attracted considerable attention. Empirical studies consistently show that sexual selection is a major drive of tail elongation. However, the genetic basis of this trait remains poorly understood. To address this gap, we performed comparative genomic analyses of 23 bird species, including 7 with extremely long tails and 16 with relative short tails. Genes related to feather development exhibited amino acid convergence replacement (e.g., APC) or displayed faster evolutionary rates (e.g., LEF1, WISP3) in the long-tailed species. Importantly, we identified convergence replacements of amino acids and rapid evolution in genes related to reproductive functions (e.g., PAQR7) and immunity (e.g., ADA), suggesting that elongated tails may serve as honest signals of genetic quality. In conclusion, this study provides genomic evidence supporting the role of sexual selection in the evolution of elongated tails, revealing an intricate interplay between sexually selected traits, fitness, and immune competence.

Species coexistence, largely maintained through mechanisms of niche differentiation, is fundamental for sustaining biodiversity and ecosystem resilience. For migratory shorebirds, the limited availability of staging sites intensifies interspecific competition, making coexistence mechanisms critical for refueling and survival during migration. This study examined the coexistence mechanisms of two threatened shorebird species, the Great Knot (Calidris tenuirostris) and Red Knot (Calidris canutus), in Nanpu wetland, a key stopover site along the East Asian-Australasian Flyway. Using noninvasive DNA metabarcoding of 81 droppings, we identified 32 MOTUs, revealing that both species primarily feed on Bivalvia. The Great Knot exhibited a more diverse diet, with Mactra quadrangularis (FOO = 71.43 %, RRA = 69.41 %) as its primary food source, whereas the Red Knot specializes in feeding on Potamocorbula laevis (FOO = 93.48 %, RRA = 80.15 %). Long-term survey data collected from 2014 to 2024 revealed that the abundance of Great Knots peaked in late April, whereas the number of Red Knots peaked 12.6 days later, in mid-May. These findings highlight how dietary differentiation and temporal partitioning enable the coexistence of these threatened species, offering valuable insights for the development of targeted conservation strategies to support species with specialized diets in adapting to fluctuations in food resources.

Billions of birds have adapted to traveling life, with the atmosphere playing an essential role in their migration. In Asia, monsoons represent a dominant large-scale circulation that may shape migration along the East Asia-Australasian Flyway. Here we combined satellite tracking of three migratory shorebirds, including Chinese egrets (Egretta eulophotes), Vega gulls (Larus vegae), and pied avocets (Recurvirostra avosetta), with analyses of monsoon index to examine how wind influence migration. We estimated flight speeds, energy use and atmosphere circulation patterns to assess the contribution of monsoon winds. The results reveal that monsoon provides substantial support to migratory shorebirds, enhancing flight speeds and reducing energetic costs, and the initiation of migration is associated with synchronous changes in monsoons systems. We suggest the monsoon creates continuous wind fields, and forms wind expressways for migratory birds in East Asia. Migratory shorebirds can leverage monsoon winds to have higher speeds along the East Asia-Australasian Flyway, reveals an analysis of satellite tracking of three bird species and monsoon indexes.

Population genomic data could provide valuable information for conservation efforts; however, limited studies have been conducted to investigate the genetic status of threatened pheasants. Reeves's Pheasant (Syrmaticus reevesii) is facing population decline, attributed to increases in habitat loss. There is a knowledge gap in understanding the genomic status and genetic basis underlying the local adaptation of this threatened bird. Here, we used population genomic data to assess population structure, genetic diversity, inbreeding patterns, and genetic divergence. Furthermore, we identified candidate genes linked with adaptation across the current distribution of Reeves's Pheasant. The present study assembled the first de novo genome sequence of Reeves's Pheasant and annotated 19,458 genes. We also sequenced 30 individuals from three populations (Dabie Mountain, Shennongjia, Qinling Mountain) and found that there was clear population structure among those populations. By comparing with other threatened species, we found that Reeves's Pheasants have low genetic diversity. Runs of homozygosity suggest that the Shennongjia population has experienced serious inbreeding. The demographic history results indicated that three populations experienced several declines during the glacial period. Local adaptative analysis among the populations identified 241 candidate genes under directional selection. They are involved in a large variety of processes, including the immune response and pigmentation. Our results suggest that the three populations should be considered as three different conservation units. The current study provides genetic evidence for conserving the threatened Reeves's Pheasant and provides genomic resources for global biodiversity management.

彩鹮Plegadis falcinellus是一种大型涉禽,隶属于鹈形目Pelecaniformes鹮科Threskiornithidae,广泛分布于欧洲南部、非洲、美洲中部、亚洲东南部和澳大利亚等地区(del Hoyo et al.,1992;郑光美,2021).彩鹮国内分布于华北、华中、华南、西南的大部分地区,以及内蒙古东部、新疆、西藏的部分地区(郑光美,2023),2021年被提升为国家一级重点保护野生动物.彩鹮在我国曾一度绝迹70年,在《中国脊椎动物红色名录》中被评估为数据缺乏(DD)物种(蒋志刚等,2016).自2009年在四川邛海被重新记录到之后(阙品甲等,2020),十余年来彩鹮在云南、江西、内蒙古和西藏等均有记录,但多为零星个体(陈丽霞等,2012;赵雪冰等,2013;卢萍等,2017;杨乐等,2019).

Hosts defend against parasites through two main strategies: resistance and tolerance. These two strategies have different influences on the parasite load of the host and so have variable effects on the fitness of parasites. In this study, we investigated the strategy used by the Barn Swallow (Hirundo rustica) to defend against a hematophagous mite (Dermanyssus hirundinis) in East Asia. For the first time, we found Barn Swallows were parasitized by D. hirundinis in Asia and, in northeastern China, over 60% of broods were parasitized. We examined whether swallows with better body condition or the males with more extravagant sexually selected traits (longer tail streamers or redder ventral plumage) showed stronger resistance or tolerance to these parasites. The results showed that males with more extravagant sexual ornaments had weaker resistance (heavier brood mite load) than males with less extravagant traits; however, the heavier mite load was likely to be a byproduct of larger brood size. Moreover, the Barn Swallow population showed strong tolerance against the parasite (i.e. the brood mite load did not affect brood size or nestling body mass). It is worth noting that male swallows with redder breast plumage showed weaker tolerance (lower seasonal reproductive success) than other males. Further, we conducted experimental ectoparasite manipulations in 46 Barn Swallow nests to verify the potential effect of these parasites on the body condition of nestlings. Neither the body mass nor the hemoglobin concentration differed between the designed groups; however, the hemoglobin concentration of nestlings decreased with mite load. We concluded that the Barn Swallow population in East Asia used the tolerance strategy, rather than resistance to defend against nest mites, and the ectoparasitic mite did not appear to be a strong selective factor for reproductive success owing to the strong tolerance of the studied Barn Swallow population. Lay Summary center dot To defend against parasites, hosts either reduce parasite burden (resistance) or compensate for parasite damage (tolerance). center dot In this study, we are the first to report the existence of a bloodsucking parasite species Dermanyssus hirundinis on Barn Swallow (Hirundo rustica) nestlings in Asia, and we investigated the swallows defense against this ectoparasite. center dot Different from previous studies which showed that Barn Swallow males with longer tails or redder plumage coloring had stronger resistance against nest mites, our results showed that such males had weaker resistance to ectoparasites in northeastern China, which was likely to be a byproduct of a larger brood size. center dot As heavier mite load did not appear to impair their reproductive success, the studied Barn Swallow population showed strong overall tolerance to these ectoparasites; however, the nest mite could still affect swallow nestling hemoglobin concentration.

Unraveling geographical modes of speciation processes has been a longstanding topic in biogeography. Divergence can be driven by factors operating on multiple spatial scales, such as geographical distance (isolation by distance, IBD), landscape resistance (isolation by resistance, IBR) and environmental heterogeneity (isolation by environment, IBE). However, it is challenging to assess the relative contributions of such factors, which are usually autocorrelated with each other. On the basis of ~294 K nuclear single‐nucleotide polymorphisms from 53 samples, we integrated population genomics, geographical information and environmental variables to delineate genetic differentiation in the common pheasant Phasianus colchicus across a longitudinal gradient in northern China. Generalized dissimilarity modeling (GDM) was used to analyze the relative importance of IBD, IBR and IBE. We found that the common pheasant in northern China was grouped into six genetic clusters, which was consistent with the taxonomic affinities. Genetic diversity changed along the longitudinal gradient, reaching its lowest level at the eastern edge of the Qinghai–Tibetan Plateau (QTP). The spatial pattern of gene flow suggested that the mountains surrounding the QTP and the mountains in central China have acted as geographical barriers impeding common pheasant dispersal. GDM analysis indicated that environmental heterogeneity is the most important driver explaining the lineage divergence, which supports the IBE model. These results suggest that multiple isolation mechanisms shaped genetic diversity and genomic divergence in this wide‐ranging bird species. Together, our results underscore the importance of leveraging genome‐wide variations and ecological modeling to facilitate a deeper understanding of population divergence processes.

Oil and its pollutants, which enter environment through natural oil seepage and many human activities, have considerable impacts on birds. We summarized the research advances in how oil pollutants influence birds and the cleaning technology of polluted birds and their habitats. The toxicity and destruction to feather structure are the major impacts of oil pollution on birds. Oil pollution can lead to birds' death, and also produce many chronic harms, including causing hemolytic anemia, reducing their immunity, disrupting thermal insulation and waterproo-fing performance of feather. It is an important way to reduce the impacts of oil pollution on birds by timely cleaning up the oil in bird habitats as well as carrying out the clean and repair work to the polluted birds. As a big oil-consuming country, China has been left behind by foreign countries in the studies of the effects of oil pollution on birds. More attention should be paid on the short-term and long-term impacts of oil pollution on birds and the cleaning and remediation technologies of the polluted birds and their habitats.

2018年之前,白冠攀雀(Remizcoronatus)在中国的已知分布范围仅限于新疆和宁夏北部.随着我国观鸟爱好者数量的增加,有人陆续在甘肃、陕西、内蒙古等地拍摄到了白冠攀雀.但由于白冠攀雀的形态特征与中华攀雀(R.consobrinus)有很多相似之处,科研人员和观鸟爱好者在野外观察过程中难以准确鉴定该物种,被误认的现象时有发生.为此,本文根据野外实地考察并参考相关文献资料,对白冠攀雀的形态特征及其与中华攀雀的差异进行了详细描述;并对其在中国的分布现状进行了更新.结果显示,白冠攀雀指名亚种(R.c.coronatus)为我国新疆西北部的夏候鸟;stoliczkae亚种为新疆北部的夏候鸟,新疆南部的冬候鸟,宁夏的夏候鸟和冬候鸟,甘肃、内蒙古和陕西的冬候鸟.