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Migratory connectivity describes the degree to which migratory populations are mixed across space and time. Unlike adults, subadult birds often exhibit distinct migratory patterns and continually refine their migratory behaviour and destinations as they mature. Consequently, the influence of subadult movements on overall migratory connectivity might be different from that of adults. However, current studies on migratory connectivity often overlook population age structures, predominantly focusing on adults. In this study, we investigated the role of subadult movements in shaping population level connectivity by using satellite tracking data from 214 black-necked cranes, Grus nigricollis , in western China. We first assessed the variances in spatial separation in different age cohorts using the continuous temporal Mantel correlation coefficient with data from 17 juveniles tracked in the same year for 3 consecutive years. We then calculated the continuous temporal migratory connectivity for the entire population (comprising various age groups) from 15 September to 15 November and compared the result to that of the family group (consisting of juveniles and adults only). Our results revealed a positive correlation between temporal variation in spatial separation and age after the juveniles separated from the adults, suggesting that subadults may have fine-tuned their migration paths. Moreover, the migratory connectivity of the all-age cohort was moderate (below 0.6) in the winter season, and notably lower than that of the family group during the autumn period. Given the considerable impact of subadults on migratory connectivity, we recommend using data collected from birds across all age categories to improve the precision of population level migratory connectivity estimates. • Black-necked cranes have moderate migratory connectivity. • Spatial separation between individuals varied between age groups. • Individuals of all ages should be included when calculating migratory connectivity. [ABSTRACT FROM AUTHOR]

Abstract Background Migratory birds exhibit heterogeneity in foraging strategies during wintering to cope with environmental and migratory pressures, and gut bacteria respond to changes in host diet. However, less is known about the dynamics of diet and gut fungi during the wintering period in black-necked cranes (Grus nigricollis). Results In this work, we performed amplicon sequencing of the trnL-P6 loop and ITS1 regions to characterize the dietary composition and gut fungal composition of black-necked cranes during wintering. Results indicated that during the wintering period, the plant-based diet of black-necked cranes mainly consisted of families Poaceae, Solanaceae, and Polygonaceae. Among them, the abundance of Solanaceae, Polygonaceae, Fabaceae, and Caryophyllaceae was significantly higher in the late wintering period, which also led to a more even consumption of various food types by black-necked cranes during this period. The diversity of gut fungal communities and the abundance of core fungi were more conserved during the wintering period, primarily dominated by Ascomycota and Basidiomycota. LEfSe analysis (P 2) found that Pyxidiophora, Pseudopeziza, Sporormiella, Geotrichum, and Papiliotrema were significantly enriched in early winter, Ramularia and Dendryphion were significantly enriched in mid-winter, Barnettozyma was significantly abundant in late winter, and Pleuroascus was significantly abundant in late winter. Finally, mantel test revealed a significant correlation between winter diet and gut fungal. Conclusions This study revealed the dynamic changes in the food composition and gut fungal community of black-necked cranes during wintering in Dashanbao. In the late wintering period, their response to environmental and migratory pressures was to broaden their diet, increase the intake of non-preferred foods, and promote a more balanced consumption ratio of various foods. Balanced food composition played an important role in stabilizing the structure of the gut fungal community. While gut fungal effectively enhanced the host’s food utilization rate, they may also faced potential risks of introducing pathogenic fungi. Additionally, we recongnized the limitations of fecal testing in studying the composition of animal gut fungal, as it cannot effectively distinguished between fungal taxa from food or soil inadvertently ingested and intestines. Future research on functions such as cultivation and metagenomics may further elucidate the role of fungi in the gut ecosystem.

Background: Migratory birds exhibit heterogeneity in foraging strategies during wintering to cope with environmental and migratory pressures, and gut bacteria respond to changes in host diet. However, less is known about the dynamics of diet and gut fungi during the wintering period in black-necked cranes (Grus nigricollis). Results: In this work, we performed amplicon sequencing of the trnL-P6 loop and ITS1 regions to characterize the dietary composition and gut fungal composition of black-necked cranes during wintering. Results indicated that during the wintering period, the plant-based diet of black-necked cranes mainly consisted of families Poaceae, Solanaceae, and Polygonaceae. Among them, the abundance of Solanaceae, Polygonaceae, Fabaceae, and Caryophyllaceae was significantly higher in the late wintering period, which also led to a more even consumption of various food types by black-necked cranes during this period. The diversity of gut fungal communities and the abundance of core fungi were more conserved during the wintering period, primarily dominated by Ascomycota and Basidiomycota. LEfSe analysis (P < 0.05, LDA > 2) found that Pyxidiophora, Pseudopeziza, Sporormiella, Geotrichum, and Papiliotrema were significantly enriched in early winter, Ramularia and Dendryphion were significantly enriched in mid-winter, Barnettozyma was significantly abundant in late winter, and Pleuroascus was significantly abundant in late winter. Finally, mantel test revealed a significant correlation between winter diet and gut fungal. Conclusions: This study revealed the dynamic changes in the food composition and gut fungal community of black-necked cranes during wintering in Dashanbao. In the late wintering period, their response to environmental and migratory pressures was to broaden their diet, increase the intake of non-preferred foods, and promote a more balanced consumption ratio of various foods. Balanced food composition played an important role in stabilizing the structure of the gut fungal community. While gut fungal effectively enhanced the host's food utilization rate, they may also faced potential risks of introducing pathogenic fungi. Additionally, we recongnized the limitations of fecal testing in studying the composition of animal gut fungal, as it cannot effectively distinguished between fungal taxa from food or soil inadvertently ingested and intestines. Future research on functions such as cultivation and metagenomics may further elucidate the role of fungi in the gut ecosystem. [ABSTRACT FROM AUTHOR]

Wintering migratory birds have to travel thousands of kilometers between their breeding and wintering grounds because of their distinct habits. They experience complex and changing survival pressures throughout the winter. This study is the first to investigate the overwintering strategies of sympatric foraging black-necked cranes and common cranes from the perspectives of food and gut microbiota. Non-invasive sampling technique was used to collect stool samples. Sanger sequencing was used to determine the origin of the crane species identified from the samples. The analysis of plant-based food, the gut microbiota, and their interactions in the faeces was performed using high-throughput sequencing technology. It was found that in environments with limited aquatic vegetation, both the black-necked crane and the common crane increased their consumption of potatoes, accounting for more than 50% of their diets. Black-necked cranes also competed with common cranes for food, and they quickly adapted to changes in diet by horizontally transmitting their gut microbiota. To meet body needs, the common cranes—which could not compete with the black-necked cranes—constantly searched for new food sources. They increase the metabolism of amino acids, lipids and these metabolites to adapt to the competitive pressures and dietary changes. This study advances our knowledge of how diet and gut microbiota interact in plateau wetland birds, examining the competitive tactics of interwintering black-necked and common cranes', and provides recommendations for the re-vegetation in the Caohai wetlands and artificial feeding of the two crane species.

The black-necked crane is the only species of crane that lives in the high-altitude region of the Tibet Plateau. At present, there is little research on viral diseases of the black-necked crane (Grus nigricollis). In this study, a viral metagenomic approach was employed to investigate the fecal virome of black-necked cranes in Saga County, Shigatse City, Tibet, China. The identified virus families carried by black-necked cranes mainly include Genomoviridae, Parvoviridae, and Picornaviridae. The percentages of sequence reads belonging to these three virus families were 1.6%, 3.1%, and 93.7%, respectively. Among them, one genome was characterized as a novel species in the genus Grusopivirus of the family Picornaviridae, four new parvovirus genomes were obtained and classified into four different novel species within the genus Chaphamaparvovirus of the subfamily Hamaparvovirinae, and four novel genomovirus genomes were also acquired and identified as members of three different species, including Gemykroznavirus haeme1, Gemycircularvirus ptero6, and Gemycircularvirus ptero10. All of these viruses were firstly detected in fecal samples of black-necked cranes. This study provides valuable information for understanding the viral community composition in the digestive tract of black-necked cranes in Tibet, which can be used for monitoring, preventing, and treating potential viral diseases in black-necked cranes. [ABSTRACT FROM AUTHOR]

IntroductionGut microbiota of wild birds are affected by many factors, and host genetic background and diet are considered to be two important factors affecting their structure and function.MethodsIn order to clarify how these two factors influence the gut microbiota, this study selected the sympatric and closely related and similar-sized Black-necked Crane (Grus nigricollis) and Common Crane (Grus grus), as well as the distantly related and significantly different-sized Bar-headed Goose (Anser indicus). The fecal samples identified using sanger sequencing as the above three bird species were subjected to high-throughput sequencing of rbcL gene and 16S rRNA gene to identify the feeding types phytophagous food and gut microbiota.ResultsThe results showed significant differences in food diversity between black-necked cranes and Common Cranes, but no significant differences in gut microbiota, Potatoes accounted for approximately 50% of their diets. Bar-headed Geese mainly feed on medicinal plants such as Angelica sinensis, Alternanthera philoxeroides, and Ranunculus repens. Black-necked cranes and Common Cranes, which have a high-starch diet, have a similar degree of enrichment in metabolism and synthesis functions, which is significantly different from Bar-headed Geese with a high-fiber diet. The differences in metabolic pathways among the three bird species are driven by food. The feeding of medicinal plants promotes the health of Bar-headed Geese, indicating that food influences the functional pathways of gut microbiota. Spearman analysis showed that there were few gut microbiota related to food, but almost all metabolic pathways were related to food.ConclusionThe host genetic background is the dominant factor determining the composition of the microbiota. Monitoring the changes in gut microbiota and feeding types of wild birds through bird feces is of great reference value for the conservation of other endangered species.

Incorporating local farmers' perceptions into conservation management has great significance because they have become the key stakeholders in wildlife conservation, especially that of waterbirds. The Black-necked Crane (Grus nigricollis) interacts closely with local farmers throughout its distribution, resulting in human–bird conflict. The evaluation of ecosystem services/disservices among local populations should help to address this relationship. We examined local farmers' perceptions of agreement with the ecosystem services and disservices provided by the Black-necked Crane in one of its large wintering sites by conducting semi-structured interviews with farmers around Caohai Wetland in Guizhou Province, China. The influences of socio-demographic variables, ecological knowledge, and attitude on farmers' agreement with ecosystem services and disservices were explored by generalized linear mixed models. Most of the farmers perceived a few benefits from the Black-necked Crane, whereas approximately one-third of them regarded the species as harmful. The most mentioned service was aesthetic value, followed by leisure and ecotourism, and therapeutic value, while crop consumption was the most commonly mentioned disservice. Their levels of agreement with services were associated with attitude and age, while those with disservices were determined by education attainment and household size. Local government and conservation organizations could use social media platforms, such as TikTok and WeChat, to convey information on the benefits or ecosystem services provided by the black-necked crane, and ecological compensation could be implemented to alleviate farmer–bird conflict. This study demonstrated the significance of the inclusion of local stakeholders and ecosystem service evaluation in conservation management. This framework can be applied to other protected species or ecosystems facing similar situations.

The Guizhou Caohai Wetland plays a crucial role as a wintering site for migratory birds in the Yunnan–Guizhou Plateau and ranks among the largest wintering spots globally for black-necked cranes (Grus nigricollis). To better understand the factors influencing waterbird populations and ecosystem changes, we conducted a comprehensive analysis of historical waterbird population variations over a 30-year period spanning from 1992 to 2022. The current investigation revealed a downward trend in the abundance index curve of the total number of waterbirds during this observation period. Among the five waterbird guilds examined, dabbling ducks, diving ducks, and coots (Fulica atra) experienced declines in their populations, while wading birds and shorebirds saw an increase. Moreover, we observed a rise in species richness within the community over time, accompanied by smaller compositional changes. Additionally, the findings indicated positive growth trends in wintering endangered species such as black-necked cranes and common cranes (Grus grus) in Caohai. Furthermore, we observed an increase in the occurrence and persistence of rare species, such as Eurasian spoonbills (Platalea leucorodia), black-faced spoonbills (Platalea minor), and black storks (Ciconia nigra) wintering in Caohai. These occurrences suggest that the wetland environment provides favorable conditions for a diverse range of species. Despite the rise in species richness, these trends in the abundance and species composition of wintering waterbirds over the past thirty years are still of concern. This study serves as fundamental scientific support for waterbird conservation and the restoration of ecological wetlands in the Guizhou Caohai Wetland. [ABSTRACT FROM AUTHOR]

Fowl adenoviruses (FAdVs) are distributed worldwide in poultry and incriminated as the etiological agents for several health problems in fowls, and are capable of crossing species barriers between domestic and wild fowls. An FAdV strain was, for the first time, isolated from black-necked crane in this study, and was designated as serotype 4 Fowl aviadenovirus C (abbreviated as BNC2021) according to the phylogenetic analysis of its DNA polymerase and hexon gene. The viral genomic sequence analysis demonstrated that the isolate possessed the ORF deletions that are present in FAdV4 strains circulating in poultry fowls in China and the amino acid mutations associated with viral pathogenicity in the hexon and fiber 2 proteins. A viral challenge experiment with mallard ducks demonstrated systemic viral infection and horizontal transmission. BNC2021 induced the typical clinical signs of hepatitis–hydropericardium syndrome (HHS) with swelling and inflammation in multiple organs and showed significant viral replication in all eight organs tested in the virus-inoculated ducks and their contactees at 6 dpi. The findings highlight the importance of surveillance of FAdVs in wild birds. [ABSTRACT FROM AUTHOR]

Less is known about the role of gut microbiota in overwintering environmental adaptation in migratory birds. Here, we performed metagenomic sequencing on fresh fecal samples (n = 24) collected during 4 periods of overwintering (Dec: early; Jan: middle I; Feb: middle II; Mar: late) to characterize gut microbial taxonomic and functional characteristics of black-necked crane (Grus nigricollis). The results demonstrated no significant change in microbial diversity among overwintering periods. Analysis of compositions of microbiomes with bias correction (ANCOM-BC) determined 15 Proteobacteria species enriched in late overwintering period. Based on previous reports, these species are associated with degradation of chitin, cellulose, and lipids. Meanwhile, fatty acid degradation and betalain biosynthesis pathways are enriched in late overwintering period. Furthermore, metagenomic binning obtained 91 high-quality bins (completeness >70% and contamination <10%), 5 of which enriched in late overwintering period. Carnobacterium maltaromaticum, unknown Enterobacteriaceae, and Yersinia frederiksenii have genes for chitin and cellulose degradation, acetate, and glutamate production. Unknown Enterobacteriaceae and Y. frederiksenii hold genes for synthesis of 10 essential amino acids required by birds, and the latter has genes for γ-aminobutyrate production. C. maltaromaticum has genes for pyridoxal synthesis. These results implied the gut microbiota is adapted to the host diet and may help black-necked cranes in pre-migratory energy accumulation by degrading the complex polysaccharide in their diet, supplying essential amino acids and vitamin pyridoxal, and producing acetate, glutamate, and γ-aminobutyrate that could stimulate host feeding. Additionally, enriched Proteobacteria also encoded more carbohydrate-active enzymes (CAZymes) and antibiotic resistance genes (ARGs) in late overwintering period. Key points: • Differences in gut microbiota function during overwintering period of black-necked cranes depend mainly on changes in core microbiota abundance • Gut microbiota of black-necked crane adapted to the diet during overwintering period • Gut microbiota could help black-necked cranes to accumulate more energy in the late overwintering period [ABSTRACT FROM AUTHOR]

Abstract Background The persistence of threatened and protected wildlife depends not only on habitat suitability but also remarkably on local communities’ acceptance. The black-necked crane (Grus nigricollis) is a flagship species for conservation on the plateau in western China. However, the human dimension has been completely ignored in the decision-making process for conservation. Methods In this study, a questionnaire survey aiming to assess knowledge of and conservation attitude toward this bird was carried out among 1042 students of 7th and 9th grade from 12 schools in Weining county, Guizhou province, which has a large wintering population in an urban wetland. Logistic regression was used in the generalized linear model to identify the determinants that significantly affect students’ knowledge of and conservation attitude toward this species. Results Most students have positive attitudes toward conservation, which is significantly affected by awareness, knowledge of this bird and grade. However, they have somewhat limited knowledge of this bird’s biology and ecosystem services (nature’s contributions to people). Knowledge was found to link with observation of the bird and grade, while observation related to the experience of visiting the wetland. Social media is the most cited resource to obtain knowledge on this bird. Conclusion It is suggested that local conservation experts could help introduce more information on the black-necked crane in the schools and help conduct outdoor education activities in and around the wetland. Traditional knowledge and culture could also be incorporated into the conservation awareness enhancing program. This study focuses on the human dimension for conserving the black-necked crane in China, showing significant implications in the design and application of effective measurements to improve students’ perception and attitude toward its conservation. Future assessments should include other local populations, such as farmers, fishers, and urban citizens.

The black-necked crane is the only species of crane that lives in the high-altitude region of the Tibet Plateau. At present, there is little research on viral diseases of the black-necked crane (Grus nigricollis). In this study, a viral metagenomic approach was employed to investigate the fecal virome of black-necked cranes in Saga County, Shigatse City, Tibet, China. The identified virus families carried by black-necked cranes mainly include Genomoviridae, Parvoviridae, and Picornaviridae. The percentages of sequence reads belonging to these three virus families were 1.6%, 3.1%, and 93.7%, respectively. Among them, one genome was characterized as a novel species in the genus Grusopivirus of the family Picornaviridae, four new parvovirus genomes were obtained and classified into four different novel species within the genus Chaphamaparvovirus of the subfamily Hamaparvovirinae, and four novel genomovirus genomes were also acquired and identified as members of three different species, including Gemykroznavirus haeme1, Gemycircularvirus ptero6, and Gemycircularvirus ptero10. All of these viruses were firstly detected in fecal samples of black-necked cranes. This study provides valuable information for understanding the viral community composition in the digestive tract of black-necked cranes in Tibet, which can be used for monitoring, preventing, and treating potential viral diseases in black-necked cranes.

Black-necked Cranes are revered as sacred birds and are considered the epitome in their biological range. They function as an umbrella species in terms of ecology ensuring that biodiversity is protected across a wider range of habitats. The study was carried out at Gangtey-Phobji valley to determine the habitat use, feeding behaviour and conservation threats of the Black-necked crane. Stratified non-random sampling was used and plot sizes of 1 x 1 m2 for herbs and 5 x 5 m2 for shrubs were used for determining the habitat use and feeding behaviour. To understand the conservation threats, a total of 129 households were surveyed. PC-ORD software was used for cluster analysis and to compute the indicator species of the habitat. A total of 50 herbs and 10 shrubs belonging to 37 families were recorded from the study area. Yushania microphylla, Juncus chrysocarpus, Rosa sericea and Rhododendron thomsonii were the indicator species of the preferred habitat. The peak flying hours were at around 08:00 a.m. and 05:00 p.m. The foraging was intensive from 09:00 a.m. to 11:00 a.m. and 03:00 p.m. to 04:00 p.m. The social (31%) and natural (31%) threats were found to be the most serious threats, followed by political threats (30%). Habitat degradation triggered by anthropogenic activities was the main threat. The cranes preferred the artificial roosts over natural ones recommending more artificial roosts for its conservation. The protection of habitats by limiting the farm road within the habitat, managing waste and stray dogs were deemed crucial.

The Guizhou Caohai Wetland plays a crucial role as a wintering site for migratory birds in the Yunnan–Guizhou Plateau and ranks among the largest wintering spots globally for black-necked cranes (Grus nigricollis). To better understand the factors influencing waterbird populations and ecosystem changes, we conducted a comprehensive analysis of historical waterbird population variations over a 30-year period spanning from 1992 to 2022. The current investigation revealed a downward trend in the abundance index curve of the total number of waterbirds during this observation period. Among the five waterbird guilds examined, dabbling ducks, diving ducks, and coots (Fulica atra) experienced declines in their populations, while wading birds and shorebirds saw an increase. Moreover, we observed a rise in species richness within the community over time, accompanied by smaller compositional changes. Additionally, the findings indicated positive growth trends in wintering endangered species such as black-necked cranes and common cranes (Grus grus) in Caohai. Furthermore, we observed an increase in the occurrence and persistence of rare species, such as Eurasian spoonbills (Platalea leucorodia), black-faced spoonbills (Platalea minor), and black storks (Ciconia nigra) wintering in Caohai. These occurrences suggest that the wetland environment provides favorable conditions for a diverse range of species. Despite the rise in species richness, these trends in the abundance and species composition of wintering waterbirds over the past thirty years are still of concern. This study serves as fundamental scientific support for waterbird conservation and the restoration of ecological wetlands in the Guizhou Caohai Wetland.

Fowl adenoviruses (FAdVs) are distributed worldwide in poultry and incriminated as the etiological agents for several health problems in fowls, and are capable of crossing species barriers between domestic and wild fowls. An FAdV strain was, for the first time, isolated from black-necked crane in this study, and was designated as serotype 4 Fowl aviadenovirus C (abbreviated as BNC2021) according to the phylogenetic analysis of its DNA polymerase and hexon gene. The viral genomic sequence analysis demonstrated that the isolate possessed the ORF deletions that are present in FAdV4 strains circulating in poultry fowls in China and the amino acid mutations associated with viral pathogenicity in the hexon and fiber 2 proteins. A viral challenge experiment with mallard ducks demonstrated systemic viral infection and horizontal transmission. BNC2021 induced the typical clinical signs of hepatitis–hydropericardium syndrome (HHS) with swelling and inflammation in multiple organs and showed significant viral replication in all eight organs tested in the virus-inoculated ducks and their contactees at 6 dpi. The findings highlight the importance of surveillance of FAdVs in wild birds.

Habitat suitability assessment is critical for wildlife population conservation and management planning. The MaxEnt model is widely used in species habitat suitability modeling. In order to investigate the habitat status of the black-necked crane in the Zoige grassland wetland ecological function area, this study evaluated the habitat suitability of the black-necked crane using the MaxEnt model with 152 occurrence records and 13 environmental variables. Based on the Akaike information criterion corrected for the small sample size, the best optimal parameter combination (feature class LQPHT, regularization multiplier 3.0) was selected. The results show that the Maxent model had good accuracy with an area under the curve (AUC) value of 0.895. Distance to roads, average summer precipitation, distance to lakes, and altitude are the dominant environmental variables affecting the potential distribution of black-necked cranes, with the contribution rates of 31.6%, 29.8%, 14.3%, and 8.2%, respectively. The suitable habitat area of black-necked cranes is mainly distributed in and around the Zoige Wetland National Nature Reserve, accounting for 46.49% of the Zoige Grassland Wetland National Key Ecological Function Zone. The potential distribution area has a tendency to spread to Hongyuan County in the south of the functional zone, and the unsuitable habitat is mainly distributed in the high-altitude area in the southwest of the functional zone. This study recommends focusing on the distribution area of black-necked cranes around Zoige Wetland National Nature Reserve and Hongyuan County to improve conservation strategies and strengthen protection efforts. [ABSTRACT FROM AUTHOR]

Black-necked crane (Grus nigricollis, BNC), facing serious threats from human activities and habitat variations, is an endangered species classified as vulnerable under the revised IUCN Red List. In this article, we investigated and analyzed the population and nesting microhabitat of BNCs in the Longbao National Nature Reserve (NNR) from 1978 to 2016, and found the number of BNCs increased from 24 in 1978 to 216 in 2016. This establishment of the Longbao NNR represented the activities of protecting endangered animal species are effective. However, the land cover classification results of Landsat images showed that the marsh wetland, which was the BNC’s primary habitat, decreased during 1978–2016, while artificial buildings increased, which affected the habitat of BNCs. The increase in average temperature over the past 40 years has also had an impact on the number of BNCs. BNCs preferred to nest in marsh wetlands or on islands with open water or star-like distributions through observation. The results of the principal component analysis showed that the nearest distance between nests and habitat type were the primary factors influencing nesting site selection. To protect BNC, we suggest decreasing wetland fragmentation, reducing habitat degradation and providing an undisturbed habitat.

Background: The persistence of threatened and protected wildlife depends not only on habitat suitability but also remarkably on local communities' acceptance. The black-necked crane (Grus nigricollis) is a flagship species for conservation on the plateau in western China. However, the human dimension has been completely ignored in the decision-making process for conservation. Methods: In this study, a questionnaire survey aiming to assess knowledge of and conservation attitude toward this bird was carried out among 1042 students of 7th and 9th grade from 12 schools in Weining county, Guizhou province, which has a large wintering population in an urban wetland. Logistic regression was used in the generalized linear model to identify the determinants that significantly affect students' knowledge of and conservation attitude toward this species. Results: Most students have positive attitudes toward conservation, which is significantly affected by awareness, knowledge of this bird and grade. However, they have somewhat limited knowledge of this bird's biology and ecosystem services (nature's contributions to people). Knowledge was found to link with observation of the bird and grade, while observation related to the experience of visiting the wetland. Social media is the most cited resource to obtain knowledge on this bird. Conclusion: It is suggested that local conservation experts could help introduce more information on the black-necked crane in the schools and help conduct outdoor education activities in and around the wetland. Traditional knowledge and culture could also be incorporated into the conservation awareness enhancing program. This study focuses on the human dimension for conserving the black-necked crane in China, showing significant implications in the design and application of effective measurements to improve students' perception and attitude toward its conservation. Future assessments should include other local populations, such as farmers, fishers, and urban citizens. [ABSTRACT FROM AUTHOR]

Black-necked cranes (Grus nigricollis) are national first-level protected wild animals in China. Artificial breeding has been adopted by many zoos and reserves to achieve ex-situ conservation of black-necked cranes, but the breeding rate of the species in cages is low. This study used non-invasive methods combined with behavioural observations to investigate changes in sex hormones and glucocorticoid metabolites in the droppings of black-necked cranes during the breeding cycle, with the results showing that (i) levels of estradiol and testosterone in black-necked cranes increased significantly when they entered the breeding period, and these levels could be used as an important physiological indicator to effectively monitor the physiological status of females and males during the reproductive period, thus providing a theoretical basis for the timing of semen collection; (ii) the level of progesterone in the mid-reproduction stage was significantly higher than that in other stages in female black-necked cranes after successful mating, and this level could be an effective indicator of the mating status of female black-necked cranes; (iii) droppings' glucocorticoid metabolites in the breeding period showed different dynamics between paired and singly caged black-necked cranes, indicating that the physiological phenomenon of reproduction could result in a certain amount of physiological burden on black-necked cranes. These results provide a theoretical basis for the selection of physiological parameters in the artificial breeding of black-necked cranes. [ABSTRACT FROM AUTHOR]

Abstract Background Understanding how overwintering birds choose foraging habitats is very important for conservation management. The overwintering Black-necked Crane (Grus nigricollis) feeds on crop remains in farmlands; thus, reasonable conservation management of this type of farmland that surrounds wetlands is critical for the overwintering populations of the Black-necked Crane; however, it is not clear how the Black-necked Crane chooses the foraging land in the farmland. Methods A thorough field positioning survey of all foraging sites in farmland areas around the Caohai Wetland and a sampling analysis of habitat selection by the Black-necked Crane were conducted during the winters from 2016‒2017 and 2017‒2018. Results Multiple factors contributed to the selection of foraging habitat in farmlands, i.e., food factors (crop remains and tillage methods) > human disturbance factors (distance to road and settlement) > topography factors (slope aspect), listed according to the strength of influence. Additionally, Black-necked Cranes tend to choose farmland sites where there was no machine tillage, the crop remains were > 500 g/m2, the distance to residences ranged from 100 to 500 m, the distance to roads ranged from 50 to 100 m, and the slopes exhibited western or eastern aspects. As the winters progressed, the volume of the edible crop remains declined, and the influences of the other main factors also changed, i.e., the factors of human disturbance (distance to road and settlement) became less important, while the effect of the food factor (crop remains) was strengthened. Thus, the foraging sites near the road became more important. Conclusion The farming area surrounding the Caohai Wetland is very important for the overwintering Black-necked Crane. Food factors and human disturbance factors are the main factors that influence the choice of feeding ground.

Ladakh lies on an important bird migratory route between the Palearctic and the Indian sub-continent, and the high altitude migratory species utilise Ladakh frequently as a stopover site. The trans-Himalayan landscape in Ladakh also serves as a breeding site for many water birds species including the globally threatened Black-necked Crane Grus nigricollis. Yet, only sporadic information is available on the status and diversity of waterbirds here. In a landscape-level assessment study spanning over 27,000km2 area, we surveyed 11 major high-altitude wetlands of Changthang Wildlife Sanctuary, Ladakh during the pre-winter season of the year 2013. We recorded a total of 38 waterbird species belonging to 10 families, including one species in Vulnerable and two species in Near Threatened categories of IUCN Red List. We calculated species diversity and richness indices to compare the wetlands. Statapuk Tso and Tsokar were the most diverse wetlands of the sanctuary (Shannon diversity 2.38 and 2.08, respectively). We used principal component analysis to find out the wetlands with unique species assemblage and identify the sites with high conservation value. We also observed a directional pattern of diversity among the wetlands of Ladakh. We provide a reminder that wildlife even in protected areas should be surveyed regularly with the sources of threats to their conservation documented carefully.

During overwintering of black-necked cranes (Grus nigricollis), the composition and function of the gut microbiota changes are of considerable interest for understanding its environmental adaption mechanism. In this study, we characterized the structure of the gut microbiota from the black-necked crane in the Dashanbao wintering area, and compared the early-winter (November) microbiota to the late-winter (March of the next year) microbiota. The results showed that the gut microbiota diversity of black-necked crane in the early-overwintering stage was higher than that in the late-overwintering stage, but it did not reach a significant level. Gut microbiota taxonomic composition analysis showed that relative abundance of Bacteroidota increased significantly, and showed decreased Firmicutes to Bacteroidota ratio at the phylum level, meanwhile, the abundance of Lactobacillus decreased significantly at the genus level. Explain gut microbiota between the early- and late-wintering showed some differences in microbiota richness but maintained a relatively conservative microbiota structure. PICRUSt2 method was used to predict and analyze the KEGG functional abundance of 16S rDNA sequences of bacteria, it was found that the changes in gut microbiota composition increased the abundance of bacteria associated with amino acid biosynthesis and acid metabolism in the late stage of overwintering. This work provides basic data for black-necked crane gut microbiota study, which might further contribute to their protection. [ABSTRACT FROM AUTHOR]

The Vulnerable Black-necked Crane Grus nigricollis is a known migrant to various locations in India. Here, we report two new locations in Arunachal Pradesh, north-east India, where one is a possible wintering location and the other a possible stopover en route their migration. One new location in Shergaon (western Arunachal Pradesh) is relatively close to previous locations; however, the one in Mechuka (central Arunachal Pradesh) is some distance away from previous records which is highly intriguing. These records of this threatened species will hopefully assist with local conservation measures, bring about more rigorous monitoring, and more surveys for these rare species in the region.

Abstract Background The Black-necked Crane (Grus nigricollis) is an internationally threatened crane living on the plateau, mainly in winter, in the Yarlung Tsangpo River basin in Tibet, western China. In the past five years, some economic development projects have been conducted in this area, posing potential threats to the wintering populations of the cranes and their habitats. Therefore, the current population dynamics of wintering Black-necked Cranes and habitat suitability in the Yarlung Tsangpo River basin were investigated. Methods Twenty counties were surveyed using the line transect method in December 2017 and January 2018, and we recorded the location, flock size, number of individuals, habitat types and presence of human disturbance in which they occurred. We compared the results from the middle wintering period in this survey with those from 2014. Results The highest number of cranes recorded was 8291, and the results showed that the cranes were mainly distributed in Lhaze, Namling, Samzhubze, and Lhunzub. A total of 577 and 495 flocks were recorded in the early and middle wintering periods, respectively. In the early wintering period, there were significant differences in the number of individuals across the different habitats, with crop stubble land and plowed land representing more than 30% of the total habitat utilization. In the middle wintering period, there were also significant differences in the number of individuals, and the utilization of crop stubble land represented over 60% of the total. Conclusions Wintering Black-necked Cranes mainly fed on spilled grains in stubble habitat after harvest. In the middle wintering period, some of the farmlands were plowed and irrigated, which resulted in food shortages in these areas, and the cranes tended to gather in mixed flocks of large size instead of as a single family. There were still considerable regional wintering populations decreases in Quxu, Nedong, and Sakya in 2018 compared with 2014, and these decreases were mainly due to some recently emerging threats, including farmlands being converted into areas of greenhouse cultivation, highway and railway construction, river dredging, the rapid development of the manufacturing and mining industries, and the lack of protection of important wintering sites.

Habitat suitability assessment is critical for wildlife population conservation and management planning. The MaxEnt model is widely used in species habitat suitability modeling. In order to investigate the habitat status of the black-necked crane in the Zoige grassland wetland ecological function area, this study evaluated the habitat suitability of the black-necked crane using the MaxEnt model with 152 occurrence records and 13 environmental variables. Based on the Akaike information criterion corrected for the small sample size, the best optimal parameter combination (feature class LQPHT, regularization multiplier 3.0) was selected. The results show that the Maxent model had good accuracy with an area under the curve (AUC) value of 0.895. Distance to roads, average summer precipitation, distance to lakes, and altitude are the dominant environmental variables affecting the potential distribution of black-necked cranes, with the contribution rates of 31.6%, 29.8%, 14.3%, and 8.2%, respectively. The suitable habitat area of black-necked cranes is mainly distributed in and around the Zoige Wetland National Nature Reserve, accounting for 46.49% of the Zoige Grassland Wetland National Key Ecological Function Zone. The potential distribution area has a tendency to spread to Hongyuan County in the south of the functional zone, and the unsuitable habitat is mainly distributed in the high-altitude area in the southwest of the functional zone. This study recommends focusing on the distribution area of black-necked cranes around Zoige Wetland National Nature Reserve and Hongyuan County to improve conservation strategies and strengthen protection efforts.

Wintering Black-necked (Grus nigricollis) and Common (G. grus) cranes occur sympatrically in Caohai Wetland, Guizhou, China. Seasonal migration dynamics, daily movement patterns, and diurnal activity budgets of the two crane species were investigated in Caohai Wetland, in order to characterize their wintering activity differences and the mechanism of interspecific coexistence, during October - April 2014 - 2017. Black-necked Cranes wintered in Caohai for 147 ± 8 days, and Common Cranes for 169 ± 8 days. Common Cranes generally arrived in Caohai 11.4 ± 3.28 days earlier and departed 11.00 ± 3.20 days later than Black-necked Cranes. During winter in Caohai Wetland, the behavioral activities of both the Black-necked and Common cranes were strongly influenced by circadian rhythms. However, there were significant differences in daily temporal patterns between them in percent time spent in specific behaviors. Common Cranes left their roosting sites 20 min. earlier than Black-necked Cranes and returned 32 min. later. Common Cranes also spent more time foraging and being vigilant than Black-necked Cranes. [ABSTRACT FROM AUTHOR]

We developed the habitat suitability criteria for the black‐necked Crane (BNC) to manage their wintering habitat in the Nyamjang Chu River in Zemithang valley, India. We generated habitat suitability criteria (HSC) curves for BNC based on the habitat availability in the river channel and use by the BNC. The HSC curves indicated that BNC preferred velocity ranged from 0 to 0.2 m/s and depth ranged from 0 to 30 cm in the river channel. Based on the HSCs of BNC, three scenarios were explored in PHABSIM: Scenario (i) increase in flow versus dry riverbed area; Scenario (ii) increase in flow versus instream suitable area; Scenario (iii) increase in flow versus weighted usable area based on combined dry and instream suitable area. The output of Scenario (i) indicated at 20 cumecs discharge achieved optimum dry riverbed area (47.07%) available for BNC, whereas Scenario (ii) predicted the different section of the river produced optimum instream area at different discharges. Though, the Scenario (iii) predicted at 20 cumecs discharge, the study area generated more than 57.38% of combined suitable habitat available for BNC. Since a proposed hydropower dam in the Zemithang valley is intend to raise water level in the river channel, it is expected to be reduced suitable habitat for BNC in the valley. Based on the PHABSIM output, we concluded that the availability of suitable habitat of BNC decreases steadily if the discharge flow increases above 20 cumecs. Moreover, the predicted average dry riverbed area (47.07%) at 20 cumecs was almost equal to the percentage of dry riverbed area (47.8%) that was naturally available during the winter. Thus, we recommend a maximum of 20 cumecs as ecological flows to maintain the minimum required habitats for wintering BNC in the Nyamjang Chu River. Consequently, the installation of the proposed dam in Zemithang valley may not be feasible. [ABSTRACT FROM AUTHOR]

Background The black-necked crane (Grus nigricollis) is a vulnerable species and the only species that lives in the plateau. Five migration routes of different populations have been identified, but for cranes wintering in Nyingchi Prefecture, Tibet, the migration route and breeding/summering area are still unknown. The aim of this study was to investigate the spatio-temporal migration patterns of black-necked cranes in this area and to identify important areas for conservation. Methods In 2016, we fitted seven black-necked cranes in Nyingchi with GPS-GSM satellite transmitters to record their migration routes. We used ArcGIS 10.2 to visualize important stopover sites and the ‘ggplot’ function in R to analyze the migration patterns. Results From March 2016 to May 2019, we recorded nine spring migration and four autumn migration tracks from five individuals. Four individuals spent the breeding/summering season in Qinghai Lake, while the other spent the breeding/summering season in the Jinzihai Wetland of Dulan County, Qinghai Province. Detailed spatio-temporal information showed that the spring migration lasted 8.7 ± 4.6 days and covered 1,182.5 ± 90.4 km, while the autumn migration lasted 30 ± 10.6 days and covered 1,455.7 ± 138 km. Basom Lake and the Shazhuyu River were the most important stopover sites during the spring and autumn migrations, respectively. The cranes spent 4.4 ± 3.7 days in Basom Lake and 26.3 ± 10.7 days in the Shazhuyu River. The black-necked cranes mainly migrated during the daytime (>85 % of the fly points), and 81 % (17/21) of all stopover and roosting sites were in the valley or at lakeside swamps. Only 17.7% (516 / 2,914) of the data points for stopover and roosting sites were in protected areas. Main conclusions Our study revealed the breeding/summering areas and migration routes of the black-necked cranes wintering in Nyingchi. These results contribute to a better understanding of the annual spatio-temporal migration patterns and the development of conservation plans for this vulnerable species.

In the autumn of 2011, both the time budget and diurnal rhythm of behavior of black-necked crane (Grus nigricollis) were studied at Altun Mountain National Nature Reserve, Xinjiang, China. The results showed that foraging was the main behavior of cranes in autumn, accounting for 69.07±1.64% of the diurnal time budget, followed by alert (19.38±0.87%), locomotion (5.97±0.49%), maintenance (2.88±0.60%) and other behavior (2.70±0.44%). In addition, we also compared the behaviors of black-necked cranes in different periods and places. The results indicate that the diurnal time budgets of cranes in autumn in breeding area are more like the wintering budget in wintering area than breeding season in breeding area. Cranes changed their diurnal time budget and behavior rhythm to adapt the environmental and social changes. [ABSTRACT FROM AUTHOR]

The black-necked crane (Grus nigricollis) is a vulnerable species, breeding exclusively on the high-altitude wetlands of the Qinghai–Tibet Plateau. Bird species harbor diverse communities of microorganisms within their gastrointestinal tracts, which have important roles in the health, nutrition, and physiology of birds. Hitherto, virtually nothing was known about the gut microbial communities associated with wild black-necked cranes. For the first time, this study characterized the gut microbial community compositions, diversity, and functions of black-necked cranes from six wintering areas in China using the Illumina Miseq platform. The taxonomic results revealed that Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes were the four most abundant phyla in the gut of black-necked cranes. At the genus level, 11 genera including Lactobacillus, Pseudomonas, Carnobacterium, Pantoea, Enterococcus, Erwinia, Turicibacter, Bacillus, Phenylobacterium, Sanguibacter, and Psychrobacter were dominant. The differences in the gut microbial community alpha and the beta diversities of black-necked cranes among the six wintering areas were investigated. Furthermore, the representative microbial taxa and their predicted functions in each wintering location were also determined. These data represent the first analysis of the gut microbiome of black-necked cranes, providing a baseline for further microbiological studies and a foundation for the conservation of this bird. [ABSTRACT FROM AUTHOR]

Background: Understanding how overwintering birds choose foraging habitats is very important for conservation management. The overwintering Black-necked Crane (Grus nigricollis) feeds on crop remains in farmlands; thus, reasonable conservation management of this type of farmland that surrounds wetlands is critical for the overwintering populations of the Black-necked Crane; however, it is not clear how the Black-necked Crane chooses the foraging land in the farmland. Methods: A thorough field positioning survey of all foraging sites in farmland areas around the Caohai Wetland and a sampling analysis of habitat selection by the Black-necked Crane were conducted during the winters from 2016‒2017 and 2017‒2018. Results: Multiple factors contributed to the selection of foraging habitat in farmlands, i.e., food factors (crop remains and tillage methods) > human disturbance factors (distance to road and settlement) > topography factors (slope aspect), listed according to the strength of influence. Additionally, Black-necked Cranes tend to choose farmland sites where there was no machine tillage, the crop remains were > 500 g/m2, the distance to residences ranged from 100 to 500 m, the distance to roads ranged from 50 to 100 m, and the slopes exhibited western or eastern aspects. As the winters progressed, the volume of the edible crop remains declined, and the influences of the other main factors also changed, i.e., the factors of human disturbance (distance to road and settlement) became less important, while the effect of the food factor (crop remains) was strengthened. Thus, the foraging sites near the road became more important. Conclusion: The farming area surrounding the Caohai Wetland is very important for the overwintering Black-necked Crane. Food factors and human disturbance factors are the main factors that influence the choice of feeding ground. [ABSTRACT FROM AUTHOR]

From July to November 2018, 10 Black-necked Crane (Grus nigricollis) juveniles were tracked using GPS-GSM satellite transmitters to study their migration routes and stopover sites in Yanchiwan Nature Reserve, Gansu Province, China. By the end of the autumn migration in November 2018, more than 25,000 GPS locations had been obtained during tracking. Migration routes, migration distances and stopover sites were determined, and the stopover home range was estimated for each individual. Individuals moved away from Yanchiwan during 2-25 October 2018 and migrated through Da Qaidam, Golmud City, Qumarleb County, Zadoi County, Zhidoi County, and Nagqu City. In mid-November 2018, the birds arrived in Linzhou County, Tibet, China to winter. The migration routes of all individuals were the same, and the average migration distance was 1,500 ± 120 km. Da Qaidam Salt Lake was an important stopover site, with an average stopover duration of 27.11 ± 8.43 d, and the average stopover range of the Black-necked Cranes at Da Qaidam was 27.4 ± 6.92 km2. Through field monitoring and satellite maps, the main habitats were determined to be grasslands and wetlands. [ABSTRACT FROM AUTHOR]

• When aquatic plants lacking, potatoes become the main food supplement of the two cranes. • Black-necked cranes adapt to new food by exchanging gut microbiota with common cranes. • Common cranes strengthen the metabolism of amino acids and lipids to adapt food changes. Wintering migratory birds have to travel thousands of kilometers between their breeding and wintering grounds because of their distinct habits. They experience complex and changing survival pressures throughout the winter. This study is the first to investigate the overwintering strategies of sympatric foraging black-necked cranes and common cranes from the perspectives of food and gut microbiota. Non-invasive sampling technique was used to collect stool samples. Sanger sequencing was used to determine the origin of the crane species identified from the samples. The analysis of plant-based food, the gut microbiota, and their interactions in the faeces was performed using high-throughput sequencing technology. It was found that in environments with limited aquatic vegetation, both the black-necked crane and the common crane increased their consumption of potatoes, accounting for more than 50% of their diets. Black-necked cranes also competed with common cranes for food, and they quickly adapted to changes in diet by horizontally transmitting their gut microbiota. To meet body needs, the common cranes—which could not compete with the black-necked cranes—constantly searched for new food sources. They increase the metabolism of amino acids, lipids and these metabolites to adapt to the competitive pressures and dietary changes. This study advances our knowledge of how diet and gut microbiota interact in plateau wetland birds, examining the competitive tactics of interwintering black-necked and common cranes', and provides recommendations for the re-vegetation in the Caohai wetlands and artificial feeding of the two crane species. [ABSTRACT FROM AUTHOR]

The black-necked crane (Grus nigricollis) which inhabits high-altitude areas has the largest body size of the world's 15 crane species, and is classified as threatened by the IUCN. To support further studies on population genetics and genomics, we present a high-quality genome assembly based on both Illumina and nanopore sequencing. In total, 54.59 Gb Illumina short reads and 116.5 Gb nanopore long reads were generated. The 1.23 Gb assembled genome has a high contig N50 of 17.89 Mb, and has a longest contig of 87.83 Mb. The completeness (97.7%) of the draft genome was evaluated with single-copy orthologous genes using BUSCO. We identified 17,789 genes and found that 8.11% of the genome is composed of repetitive elements. In total, 84 of the 2,272 one-to-one orthologous genes were under positive selection in the black-necked crane lineage. SNP-based inference indicated two bottlenecks in the recent demographic trajectories of the black-necked crane. The genome information will contribute to future study of crane evolutionary history and provide new insights into the potential adaptation mechanisms of the black-necked crane to its high-altitude habitat. [ABSTRACT FROM AUTHOR]

Introduction: Gut microbiota of wild birds are affected by many factors, and host genetic background and diet are considered to be two important factors affecting their structure and function., Methods: In order to clarify how these two factors influence the gut microbiota, this study selected the sympatric and closely related and similar-sized Black-necked Crane ( Grus nigricollis ) and Common Crane ( Grus grus ), as well as the distantly related and significantly different-sized Bar-headed Goose ( Anser indicus ). The fecal samples identified using sanger sequencing as the above three bird species were subjected to high-throughput sequencing of rbcL gene and 16S rRNA gene to identify the feeding types phytophagous food and gut microbiota., Results: The results showed significant differences in food diversity between black-necked cranes and Common Cranes, but no significant differences in gut microbiota, Potatoes accounted for approximately 50% of their diets. Bar-headed Geese mainly feed on medicinal plants such as Angelica sinensis, Alternanthera philoxeroides , and Ranunculus repens . Black-necked cranes and Common Cranes, which have a high-starch diet, have a similar degree of enrichment in metabolism and synthesis functions, which is significantly different from Bar-headed Geese with a high-fiber diet. The differences in metabolic pathways among the three bird species are driven by food. The feeding of medicinal plants promotes the health of Bar-headed Geese, indicating that food influences the functional pathways of gut microbiota. Spearman analysis showed that there were few gut microbiota related to food, but almost all metabolic pathways were related to food., Conclusion: The host genetic background is the dominant factor determining the composition of the microbiota. Monitoring the changes in gut microbiota and feeding types of wild birds through bird feces is of great reference value for the conservation of other endangered species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wang, Long, Zhang, Li, Zhang and Su.)

Disseminated visceral coccidiosis (DVC) is a widely distributed intestinal and extraintestinal disease of cranes caused by eimeriid coccidia and has lethal pathogenicity to several crane species. Here, feces of 164 black-necked cranes collected in Dashanbao Black-necked Crane National Nature Reserve, China, were examined to determine the prevalence of coccidial oocysts. Of the 164 fecal samples, 76 (46.3%) were positive for oocysts of Eimeria, including E. gruis in 59 (35.9%), E. reichenowi in 52 (31.7%), and E. bosquei in 47 (28.7%) by microscopic observation. Sixty-eight (89.5%) of these positive samples included two or more morphologically identifiable species of Eimeria. The nearly full length 18S rRNA gene (18S rRNA; about 1.8 kb) and partial mitochondrial cytochrome c oxidase I gene (COX1; about 1.3 kb) from oocysts of each morphologically distinct species of Eimeria were amplified, sequenced, and analyzed. BLAST searches using these new 18S rRNA sequences for E. gruis, E. reichenowi, or E. bosquei showed the most similar sequences were those of E. gruis (98.7–99.7% identity), E. reichenowi (97.9–100% identity), or E. gruis (98.6–99.6% identity) isolated from different species of Grus. BLAST searches using the new COX1 sequences for the three species of Eimeria showed that no nucleotide sequences of Eimeria and Isospora coccidia in GenBank have more than 83.0% identity with these species. Identities among the new COX1 sequences were 91.8% for E. gruis and E. reichenowi, 94.5% for E. gruis and E. bosquei, and 91.3% for E. reichenowi and E. bosquei. Phylogenetic analysis based on 18S rRNA or COX1 sequences indicated that Eimeria spp. in black-necked cranes were clustered together with other previously identified Eimeria species from different cranes. [ABSTRACT FROM AUTHOR]

We investigated population dynamics, breeding pairs, breeding habitat selection, nest density, distance between neighboring nests, nest survival, reproductive success, and recruitment rate for Black-necked Cranes (BNC, Grus nigricollis) during 2013–2015 in Yanchiwan National Nature Reserve (YCW), Gansu, China. Numbers of BNC and breeding pairs remained relatively stable at around 140 individuals and 40 pairs. Recruitment rates ranged from 15.7% to 25.8%. The average nest distance was 718.66 ± 430.50 m (2013), 1064.51 ± 323.99 m (2014) and 534.99 ± 195.45 m (2015). Average nest survival rate, hatching success, and breeding success of all 29 nests were 65.56 ± 5.09%, 57.04 ± 6.12% and 32.78% ± 2.55. Water depth, water body area, and distance to land were positively related to nest survival, while disturbance level showed a negative relationship. However, nest site selection of BNC was determined by habitat type, disturbance and water depth. BNC often foraged in mudflats and freshwater marsh but seldom foraged in saline-alkali wet meadows due to food density and quantity in April, the month when BNC choose nest sites. Conservation strategies based on habitats should consider ecological factors that may not be well predicted by nest site selection. Shifts within core-use areas from satellite tracking of BNC demonstrated that maintaining populations demands that conservation areas are large enough to permit breeding BNC changes in space use. Our results are important for conservation management and provide quantitative reproductive data for this species.

Sequential randomness is one of the three important assumptions for Pulliam’s vigilance model (1973). Here we tested the sequential randomness in Black-necked cranes Grus nigricollis , to see if the vigilance sequence can be predicted. Not similar to other recent studies, we found that most vigilance sequences (44/46) passed runs randomness test, and the length of an inter-scan interval was usually unrelated to its previous scan duration. Our findings suggest high predation risk might favor a random pattern of vigilance. [ABSTRACT FROM AUTHOR]

Background: The behavior of cranes reflects many of their survival strategies, but little has been known of the incubation strategies of cranes, in which both parents share incubation duties, in response to cold temperatures in alpine environments. The lack of information may restrict the effective conservation of the threatened Black-necked Crane (Grus nigricollis), a biparental bird nesting in high elevation wetlands. Methods: We directly observed and used infrared video cameras from 2014 to 2015 to study the incubation behavior and quantitatively measured the frequency and details of egg turning behavior in the Black-necked Crane at the Yanchiwan National Nature Reserve in western Gansu Province, China. Results: At lower ambient temperatures in the morning, crane parents spent more time on the nest with less recess frequency and prolonged on-bout duration, while at higher temperatures around noon, the parents had more frequent recesses from incubation and shorter periods between nest exchanges. They adjusted the amount of time incubating by varying the recess frequency and the length of on-bout duration. Mean nest attendance and egg turning frequency of females were significantly higher than those of the males. The nest attendance and on-bout duration of females showed a significantly negative relationship with those of males. The two parents responded differently to the change of temperature. Females spent more time on the nest at lower morning temperatures, while males increased their time on the nest at higher temperatures after noon. Higher incubation recess frequency and egg turning frequency were observed at noon, probably because parents spent more time foraging, taking advantage of the lower egg cooling rate. Conclusion: Both Black-necked Crane parents in the alpine environment adjusted their behavior in response to the thermal requirements of eggs and the weather conditions experienced. Our findings demonstrate that parents of this species incubated in different but complementary ways and efficiently enhanced egg care in a dynamic environment, so as to maximize benefits from the warm portion of the day and the intense solar radiation while minimizing the cost of rewarming eggs and the risks of cooling eggs. [ABSTRACT FROM AUTHOR]

Cranes usually roost in shallow water, while large numbers of cranes roosting in a waterless environment are rarely reported. We document novel upland roosts used by the Black-necked Crane ( Grus nigricollis) wintering at Yongshan in northeast Yunnan, China. A total of 45 upland roost sites were recorded in the winters of 2012-2013 and 2013-2014. The roost sites were on upper slope positions (0.74 ± 0.17, 0.34-1.00) of steep mountain slopes (28 ± 5°, 20-40°) above stream valleys, with the roost at 95 ± 30 m, 32-175 m from the foot of its hill, and often had a platform or flat space (21 out of 45). The roost sites occurred in three habitats: shrub forest, grassy terrace, and natural grassland-bare land. We found that the pattern of roost site use is different from that of Black-necked Cranes in other wintering areas, as well as that of other species in the family Gruidae. This discovery suggests Black-necked Cranes may be more flexible and less reliant on wetlands for nocturnal roost use than we previously perceived. Further research on roost selection is needed to more thoroughly understand the behavior of the Black-necked Crane and for the conservation and management of this species. [ABSTRACT FROM AUTHOR]

The Black-necked Crane Grus nigricollis is a globally vulnerable species whose food is the factor determining its long-term survival. Understanding dietary habits, food preferences, and related factors will facilitate the development of effective conservation plans for the protection of this vulnerable species. For this purpose, we used video recordings and sampling of food availability to examine the dietary composition and temporal variation in food selection of Black-necked Cranes wintering in the Dashanbao National Nature Reserve, China. The Black-necked Crane’s diet consists primarily of domestic food crops such as grains (74%) and potatoes (8%), in addition to invertebrates (14%). A much smaller proportion of the diet was comprised of turnips and wild herbaceous plants and tubers. There was monthly variation in food selection, partially related to food availability. Grains were most available in November and decreased through the winter, whereas invertebrates were more available in November and February than in December and January. Grain consumption was lowest in November but higher from December through February. Invertebrate consumption was highest in November and February. The cranes preferred to eat grains throughout winter months, while they mainly selected invertebrates in November and February. We suggested invertebrate populations sharply declined in December and January due to the low temperature. In addition, grain consumption was negatively associated with invertebrate availability. In November, when invertebrates were most abundant, and despite a concomitant peak in grain abundance, we suggested cranes exhibited a preference for invertebrates over grains. We recommend that the protection administration provide appropriate supplemental foods for cranes during freezing weather.

Weather conditions considerably influence the behavior of wildlife, particularly those living in harsh habitats such as the plateau. In this study, we reported unusual flight behavior of Black-necked Cranes ( Grus nigricollis) where legs are drawn up. Among 15 crane species, it is the only species that spends its entire life in alpine areas. Field observations were conducted during the three winters of 2006/07, 2009/10, and 2012/13 at Dashanbao National Nature Reserve (DNNR), northeastern Yunnan, China. At the population level, ~4% of Black-necked Cranes displayed this behavior, whereas a total of 156 individuals from 49 flocks displayed this behavior among the clearly observed 4,007 individuals of 751 crane flocks. Our results showed a strong negative correlation between prevalence of this behavior and departure temperature ( r = −0.832, P = 0.005, n = 9). Moreover, the average temperature of the preceding 12 hrs and duration of exposure to subzero temperature had a significant effect on the occurrence of leg-drawn-up flight behavior ( P < 0.05), whereas the extreme low temperature of the preceding 12 hrs did not significantly affect the prevalence of this behavior ( F1,3 = 1.974, P = 0.26). We inferred that this infrequent flight posture developed as a behavioral response to the low air temperature and duration of exposure. [ABSTRACT FROM AUTHOR]

Vigilance is a behavior in birds that is used to detect predators and monitor rivals, and it can be affected by several environmental and social factors, including group size. Here, Black-necked Cranes ( Grus nigricollis) were observed in winter in the Yarlung Zangbo Nature Reserve, Tibet, China, to examine the effect of group size on vigilance behavior at both the individual and group levels. At the individual level, individual Black-necked Cranes in large social groups spent less time in vigilant behavior than when in small family groups. At the social group level, the proportion of vigilant individuals decreased, while the proportion of intervals that at least one individual was vigilant increased, with increasing group size. There was a significant group size effect on vigilance behavior in wintering Black-necked Cranes at both of these levels. [ABSTRACT FROM AUTHOR]

The article discusses a research study about a summer breeding survey of waterbird abundance and distribution in Tibet, China. Topics cited include the species of waterbird, main long-term threat to lakes in the Changtang region, types of habitat, and the diversity between the different salinity of the lakes.