摘要: Bacterial infections of avian embryos can lead to an increase in embryo mortality, and the proliferation of antimicrobial-resistant bacteria aggravates the situation. A low hatching rate also poses a challenge to the population of artificially bred Crested Ibises(Nipponia nippon). This study aims to determine the potential association between bacterial infection and the death of Crested Ibis embryos, and whether there is convergence between antimicrobial resistance and virulence in strain. In this study, 13 Escherichia coli and 12 Proteus mirabilis isolates were recovered from dead Crested Ibis embryos. The pathogenicity examination confirmed the pathogenicity of all isolates, and multiple virulence genes detected by PCR-sequencing demonstrated the presence of irp2 and iuc D(100%), fim C and iss(92.31%) in E. coli, and uca A(58.33%) in P. mirabilis. Antimicrobial susceptibility test demonstrated that isolates were mainly resistant to amoxicillin(E. coli: 76.92%, P. mirabilis: 91.67%), cefazolin(E. coli: 76.92%, P. mirabilis: 91.67%), oxytetracycline(E. coli: 92.31%, P. mirabilis: 75.00%) and sulfamethoxazole-trimethoprim(E. coli: 53.85%, P. mirabilis: 33.33%), and more than 30% of isolates showed multidrug-resistance(MDR). Further analyses detected extended-spectrum β-lactamase(ESBL) genes, of which blaTEM-1(E. coli: 100%, P. mirabilis: 100%) had the highest frequency, followed by the blaCTX-M-55(E. coli: 92.31%, P. mirabilis: 50%), blaCTX-M-14(E. coli: 76.92%, P. mirabilis: 33.33%), blaCTX-M-65(E. coli: 15.38%, P. mirabilis: 16.67%), and all isolates were negative for blaSHV and blaOXA. Pearson's correlation analysis showed a positive correlation between the presence of β-lactam resistance and ESBL genes, while mainly negative correlations were observed between the presence of ESBL genes and virulence genes. Furthermore, the conjugation experiment and PFGE revealed that the isolates were primarily polyclonal, and there was horizontal transfer of resistance or virulence genes by plasmids. Based on the results, E. coli and P. mirabilis were responsible for embryonic mortality of the ibises in this study. The co-presence and co-transfer of ESBL genes and virulence genes can pose a potential threat to the health of the Crested Ibis, and measures such as prudent use of antimicrobials, and constant surveillance of resistance and pathogenicity, must be implemented at the Crested Ibis breeding base.

摘要: Climate change can affect rainfall and temperature worldwide, and the ability of birds to react to these changes can be mirrored by studying population phenology and their breeding success. Some European species have advanced arrival and breeding dates in response to local spring advancement, but conditions experienced during winter seasons may also affect arrival dates and subsequent breeding success. We utilized data collected from 1983 to 2020 in four colonies of Common Swift(Apus apus) in Northern Italy(5486 breeding attempts) to examine the variations of laying date and breeding success in relation to non-breeding conditions(previous winter in Africa) and local conditions in breeding period(spring). Climatic conditions were monitored using the North Atlantic Oscillation(NAO) and El Nino Southern Oscillation(ENSO) indices to describe conditions experienced in winter quarters and the local temperature and rainfall conditions of the breeding area. Common Swifts laid their eggs earlier in warmer springs, and this in turn had a positive effect on breeding success. We did not find evidence for any effects of African winter conditions on laying date nor on breeding success. However, because studies made in the same area have demonstrated a relationship of winter conditions(NAO) on individual survival, our data highlight the importance of considering environmental variables across the annual life cycle to understand variation in Common Swift populations.

摘要: Evaluating the habitat suitability of flagship species and its key influencing factors is vital for understanding potential conservation issues and developing coping strategies. We surveyed the wintering population size and distribution of the Black-necked Crane（Grus nigricollis） in the Yarlung Zangbo River Basin（YZRB） from 10 to 29 January 2022, and predicted the current potentially suitable habitat distribution and its effective factors using the Max Ent model. A total of 9337 wintering Black-necked Cranes were recorded in the YZRB in 2022, 76.58 % of which were primarily found in Lhunzub, Samzhubze, Namling, and Lhaze. Compared to 2018, the crane population has exhibited a notable decline in Samzhubze and Taktse, likely due to farmland plowing, winter irrigation, changes in agricultural practices, road construction and hydraulic projects. The crane population within various counties exhibited a significant positive correlation with the suitable habitat area（r =0.70, P =0.002, n =17）. We also found that the currently suitable habitat area covered 17,204 km², of which only 3244 km²（18.86 %） was effectively protected at the national level, which was predominantly distributed in farmland and rangeland habitats characterized by gentle slopes, altitudes not exceeding 4500 m, and proximity to human settlements along rivers, where suitable isothermal values（51） and less seasonal precipitation（20 mm） prevail. Our study will be helpful for formulating reasonable conservation strategies to protect the core population of this threatened highland flagship species.

摘要: Free-ranging yak grazing is a regime specially adapted to high-elevation environments across the Pan-Tibetan Highlands, yet its impacts on alpine birds remain poorly understood. The Chinese Monal(Lophophorus lhuysii) is a rare pheasant species that serves as a representative and umbrella species for alpine meadow ecosystems in the mountains of Southwest China, and has long been regarded as threatened by free-ranging yaks. However, the actual impacts and specific mechanisms through which yak grazing influences Chinese Monal have not been empirically tested. Here, we conducted infrared camera monitoring in alpine meadows within the Wolong National Nature Reserve, Sichuan, China, from 2019 to 2022. We analyzed the effects of free-ranging yaks on habitat occupancy, activity pattern, and population density of the Chinese Monal using multispecies occupancy models, kernel density estimations, avoidance attraction ratios, and random encounter models. We found that interactions with yaks affect monal habitat occupancy in conjunction with other ecological factors. Specifically, the presence of yaks alters monals' occupancy responses to variations in grass cover and elevation, causing monals to use habitats with lower grass cover and elevation more frequently. Additionally, the activity patterns of the Chinese Monal and yaks are significantly different, and the presence of yaks significantly prolongs the time until monals re-occupy the same habitats. As an outcome of the cumulative effects of spatial and temporal avoidance, the population density of the Chinese Monal negatively correlated with increasing grazing intensity. This study provides the first empirical evidence of the negative impacts of free-ranging yaks on the Chinese Monal and elucidates the underlying mechanisms, highlighting great risks to conservation of this vulnerable species. Our findings inform the optimization of grazing management that balances production with conservation. Strict control over yak numbers and grazing areas in critical habitats for Chinese Monal and other threatened species could be a feasible compromise to mitigate these pressures.

摘要: The Natural Forest Protection Project（NFPP）, initiated by the Chinese government in 2000, is a crucial ecological construction project that has played a significant role in forest restoration in China. Forests in the Qinghai-Tibet Plateau（QTP） serve as important habitats for many rare and endemic birds. Understanding the conservation efficiency of NFPP implementation on these birds holds significant practical significance. In this study, we utilized land use change matrices to analyze the forest changes in the QTP before and after NFPP implementation, predicted the potential spatial distribution of 16 nationally protected birds using Species Distribution Models（SDMs）, and compared the impacts of this project on bird habitats under different carbon emission scenarios. Mann-Whitney U tests were employed to analyze the adaptation of different birds to forest changes during NFPP implementation. Our results showed that NFPP protected 172,398 km² of primary forests and added 6379 km² of secondary forests in our study area. The potential spatial distribution and sympatric species richness of the 16 protected birds slightly increased after NFPP implementation under different climate change scenarios, and NFPP implementation contributed to improving the potential spatial distribution of birds. Compared to newly established secondary forests, protected primary forests exhibited enhanced conservation for forest birds（Z-value >0 for six bird species, P < 0.1）, while being less suitable for non-forest birds（significantly unsuitable for three non-forest bird species, Z-value < 0, P < 0.05; non-significantly unsuitable for four non-forest bird species, Zvalue < 0, P > 0.1）. This indicates that the protection of primary forests during NFPP implementation benefits forest bird conservation while the addition of secondary forests is beneficial to non-forest birds. To enhance the role of NFPP in avian conservation in the QTP, it is suggested to increase the landscape heterogeneity of forest, particularly in newly established secondary forests.

摘要: Abundant food supply is crucial for the survival of long-distance migratory birds. The continued population decline of the Spoon-billed Sandpiper(Calidris pygmeae), a critically endangered shorebird, is primarily attributed to habitat loss and degradation. However, significant gaps remain in research on their diet and foraging habitat selection, limiting effective conservation and restoration efforts. In this study, we investigated the composition of macrobenthic communities, analyzing habitat and prey selection at the main foraging area of SBS in Tiaozini, Jiangsu Province of eastern China—their most critical staging site during southward migration. Our findings revealed 25 species of macrobenthos in foraging areas, with mobile epibenthos comprising the largest group by biomass, accounting for 73%, and having higher density and biomass nearshore. Observations of foraging Spoon-billed Sandpiper individuals indicated that shallow water habitats were their preferred foraging environments, where mobile epibenthos, which thrive in these habitats after the tide recedes, made up 81% of their biomass intake. We propose that shallow water habitats in intertidal mudflats serve as essential refuges for mobile epibenthos after tidal retreat, thereby providing Spoon-billed Sandpipers with access to high-quality food resources. Habitat protection efforts should prioritize habitats harboring extensive microhabitats with shallow water, especially the nearshore area, and further research is needed to explore the mechanisms underlying the formation of these microhabitats, with the ultimate goal of restoring more high-quality habitats for the Spoonbilled Sandpiper.

摘要: Passerine mimics often imitate various vocalizations from other bird species and incorporate these sounds into their song repertoires. While a few anecdotes reported that wild songbirds imitated human-associated sounds,besides captive parrots and songbirds, systemic and quantitative studies on human-made sound mimicry in wild birds remain scarce. In this study, we investigated the mimetic accuracy and consistency of electric moped sounds imitated by an urban bird, the Chinese Blackbird(Turdus mandarinus). We found that:(1) Only one type of electric moped sound was imitated, i.e., 13 of 26 males mimicked the first part of the antitheft alarm, a phrase containing a series of identical notes.(2) The mimicry produced by male Chinese Blackbirds had fewer notes and lower consistency within phrases compared to the model alarms.(3) The mimicry of male Chinese Blackbirds was imperfect, i.e., most of the acoustic parameters differed from the model alarms. Additionally, mimetic notes were lower in frequency than the models. Mimetic notes from two areas were also different in acoustic structures,suggesting Chinese Blackbirds might learn mimicry mainly from conspecific neighbors within each area respectively rather than electric mopeds, namely the secondary mimicry. Imperfect mimicry of human-made sounds could result from cost and physical constraints, associated with high consistency, frequency, and repetitions. Consequently, Chinese Blackbirds copied a simplified version of electric moped alarms. We recommend further attention to mimic species inhabiting urban ecosystems to better understand vocal mimicry's adaptation to ongoing urbanization.

摘要: Avian vocal communication represents one of the most intricate forms of animal language, playing a critical role in behavioral interactions. Both peripheral and central auditory-vocal pathways are essential for precisely integrating acoustic signals, ensuring effective communication. Like humans, songbirds exhibit vocal learning behaviors supported by complex neural mechanisms. However, unlike most mammals, songbirds possess the remarkable ability to regenerate damaged auditory cells. These capabilities offer unique opportunities to explore how birds adjust their vocal behavior and auditory processing in response to dynamic environmental conditions. Recent studies have advanced our understanding of the plasticity of avian vocal communication system, yet the vocal diversity and neurophysiological mechanisms underlying vocalization and hearing have often been examined independently. A comprehensive overview of how these systems interact and adapt in birds remains lacking. To address this gap, this review synthesizes the peripheral and central features of avian vocalization and hearing, while also exploring the mechanisms that drive the remarkable plasticity of these systems. Furthermore, it explores seasonal variations in bird vocalization and hearing and adaptations to environmental noise, focusing on how hormonal, neural, and ecological factors together shape vocal behavior and auditory sensitivity. Avian vocal communication systems present an exceptional model for studying the integration of peripheral and central vocal-auditory pathways and their adaptive responses to ever-changing environments. This review underscores the dynamic interactions between avian vocal communication systems and environmental stimuli, offering new insights into broader principles of sensory processing, and neuroplasticity.

摘要: In brood-parasitic Cuculus cuckoos, male vocalizations are species-specific and easily distinguishable, whereas female calls are remarkably similar across species, making species identification challenging. In this study, we examined the structural characteristics and variability of female bubbling calls among four Cuculus species(Common Cuckoo C. canorus, Oriental Cuckoo C. optatus, Indian Cuckoo C. micropterus, and Lesser Cuckoo C. poliocephalus) breeding in South Korea. Comprehensive acoustic analyses of seven call parameters, using recordings from 2021 to 2023, were conducted to quantify the characteristics of their calls and compare withinand between-individual variability across species. Significant differences were found across all call parameters, with the Common Cuckoo producing the highest number of notes and the Oriental Cuckoo the lowest-frequency calls. Despite these differences, the overall structure of the calls remained acoustically similar, with overlapping characteristics across species. Furthermore, female Common Cuckoos exhibited greater within-individual variability in their calls, while the other species showed higher between-individual variability, which may further complicate species identification based vocalization alone. These findings highlight the complexities of female vocalizations in Cuculus cuckoos and suggest that ecological, social, and evolutionary factors may contribute to this vocal variability.

摘要: Avian brood parasitism is a unique reproductive behavior in which parasitic birds depend on other species to incubate their eggs and raise their offspring. In China, there are 20 species of cuckoos in the family Cuculidae, order Cuculiformes, of which 17 species are parasitic cuckoos. This makes China one of the countries with the largest number of parasitic cuckoo species worldwide. Understanding the host utilization of cuckoos provides fundamental data for studying the coevolution of cuckoos with their hosts. We collected information on cuckoo hosts from the literature, photographs provided by birdwatchers, and online short video platforms, combined these data with our field observations, and summarized the parasitic cuckoos and their host species in China. A total of 1155 parasitism events were counted, involving 12 parasitic cuckoo species and 87 bird host species. These hosts belonged to 26 families, among which Muscicapidae was the most diverse with 19 species, accounting for 21.8% of the total hosts, followed by the families Phylloscopidae and Leiothrichidae with 8 species each, accounting for 9.2% of the total hosts recorded. The Common Cuckoo(Cuculus canorus) had the largest number of host taxa with 38 species, accounting for 43.7% of the total host species. This study adds 14 host species that have not been reported in China. However, for five species, the Jacobin Cuckoo(Clamator jacobinus), Banded Bay Cuckoo(Cacomantis sonneratii), Violet Cuckoo(Chrysococcyx xanthorhynchus), Common Hawkcuckoo(Hierococcyx varius), and Whistling Hawk-cuckoo(Hierococcyx nisicolor), information regarding host utilization is still lacking.