Gut fungi of black-necked cranes (Grus nigricollis) respond to dietary changes during wintering.

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.

Gut microbiota enhance energy accumulation of black-necked crane to cope with impending migration.

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.

Structural changes in the gut microbiota community of the black-necked crane (Grus nigricollis) in the wintering period.

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.

Characterization of the gut microbiome of black-necked cranes (Grus nigricollis) in six wintering areas in China.

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.

Seasonal changes in invertebrate diet of breeding black-necked cranes (Grus nigricollis).

Invertebrates greatly support the growth, development, and reproduction of insectivorous birds. However, the influence of human activity (e.g., pesticide use, deforestation, and urbanization) inevitably leads to a decrease in global arthropods. The diversity and variation in invertebrate diet influence the food composition of birds, especially species living in rapidly changing environments, such as the Tibetan Plateau. However, little is known of the seasonal variation in invertebrate diet in response to environmental changes. Here, we characterized the invertebrate diet composition in pre- and post-breeding black-necked crane (Grus nigricollis) using fecal metabarcoding. We identified 38 invertebrate genera; the top three were Tipula (82.1% of relative abundance), Ceramica (3.0%), and unclassified_Hymenoptera (2.5%), with Tipula predominated the diet in both seasons. We also observed 20 and 16 unique genera in the pre- and post-breeding periods, and the genera composition was distinct between seasons (R = .036, p = .024). In pre-breeding, black-necked cranes tended to consume more diverse foods, and individual cranes exhibited greater heterogeneity at the genus level. At the genera and species level, pre-breeding black-necked cranes showed a wider dietary niche than post-breeding cranes. We observed season-specific features, with Tipula (common crane fly) and Stethophyma (grasshoppers) being enriched in the post-breeding period and Ceramica (moth) being more abundant in the pre-breeding period. Three Tipula species had the greatest importance in discriminating between seasonal diets. This study demonstrated a seasonal pattern of invertebrate diet in the black-necked crane, suggesting diet composition in response to resource and species availability. These results elaborate on the foraging ecology of highland birds and can inform the management of black-necked crane conservation.

Identification of Multiple Novel Viruses in Fecal Samples of Black-Necked Cranes Using Viral Metagenomic Methods.

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.

Host genetic background rather than diet-induced gut microbiota shifts of sympatric black-necked crane, common crane and bar-headed goose.

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.

Changes in the landscape patterns of Black-necked Crane habitat and its correlation with their individual population numbers during the past 40 years in China.

The landscape pattern of the Black-necked Crane (Grus nigricollis) habitat in China changed at different spatial scales and long-term periods due to natural factors and human activities, and habitat reduction and fragmentation threatened the survival of Black-necked Cranes. The factors driving the habitat landscape pattern and individual population changes of Black-necked Cranes remain to be studied. In this paper, based on remote sensing data of land use from 1980 to 2020, the changes in landscape pattern and fragmentation of the Black-necked Crane habitat in China over 40 years were analyzed from two different spatial scales using the land cover transfer matrix and landscape index. The correlation between landscape and Black-necked Crane individual population was analyzed. The most obvious observations were as follows: (1) Although transformation between landscapes occurred to varying degrees, the area of wetlands and arable land in the breeding and the wintering areas (net) increased significantly from 1980 to 2020. (2) Habitat fragmentation existed in the breeding and the wintering area and was more obvious in the wintering area. (3) The number of individuals of Black-necked Cranes increased period by period, and habitat fragmentation did not inhibit their population growth. (4) The number of individuals of Black-necked Crane was closely related to the wetland and arable land. The increasing area of wetlands and arable and the increasing landscape shape complexity all contributed to the growth of the individual population. The results also suggested that the number of individuals of Black-necked Crane was not threatened by the expanding arable land in China, and they might benefit from arable landscapes. The conservation of Black-necked Cranes should focus on the relationship between individual Black-necked Cranes and arable landscapes, and the conservation of other waterbirds should also focus on the relationship between individual waterbirds and other landscapes.

Genomic and Pathologic Characterization of the First FAdV-C Serotype 4 Isolate from Black-Necked Crane.

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.

Dynamic changes in the hormones of black-necked cranes during reproduction.

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.

Students' knowledge of and conservation attitude toward the black-necked crane (Grus nigricollis) in Guizhou, China: insights for conservation.

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.

Distribution of Breeding Population and Predicting Future Habitat under Climate Change of Black-Necked Crane (Grus nigricollis Przevalski, 1876) in Shaluli Mountains.

Climate change is affecting biodiversity by altering the geographical distribution range of species, and this effect is amplified in climate-sensitive areas. Studying the geographic distribution of flagship species in response to climate change is important for the long-term conservation of species and the maintenance of regional biodiversity. Therefore, we collected field survey records from 2016 to 2020 and conducted field surveys of black-necked cranes in the Shaluli Mountains (SLLMs) in May-June and August-October 2021; 103 breeding records were acquired totally, and the geographical distribution range under the current and four future climate scenarios was modeled with the MaxEnt model to predict the impact of climate change on its distribution and habitat quality. The results showed that 152 black-necked cranes were surveyed in seven counties of SLLMs in total; the estimated number of black-necked cranes in the entire SLLMs was about 200. The currently suitable habitat area is 27,122 km2, mainly distributed in gentle meadows and wetland habitats along the lake where the Annual Mean Temperature is -1 °C and the Mean Diurnal Range (16 °C) and Precipitation Seasonality (105) are comparatively large. Furthermore, the breeding range would expand to varying degrees under future climate scenarios and showed a migration trend toward the northwest and higher elevation. Besides, as time goes by, the habitat for black-necked cranes in SLLMs would become more homogeneous and more suitable. The conservation effectiveness of the existing reserve network would keep stable with climate change, although there are large conservation gaps between protected areas, and these gaps will gradually expand over time. Overall, this study provides a preliminary understanding of the population and distribution and predicts the future distribution of black-necked cranes in the SLLMs. It also demonstrates the importance of SLLMs for protecting the central population of black-necked cranes and maintaining regional biodiversity. Therefore, we recommend long-term monitoring and conservation of the black-necked crane population and wetland resources in the region.

Satellite tracking reveals a new migration route of black-necked cranes (Grus nigricollis) in Qinghai-Tibet Plateau.

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.

A High-Quality Draft Genome Assembly of the Black-Necked Crane (Grus nigricollis) Based on Nanopore Sequencing.

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.

Nest-site selection, reproductive ecology and shifts within core-use areas of Black-necked Cranes at the northern limit of the Tibetan Plateau.

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.

Why choose Random Forest to predict rare species distribution with few samples in large undersampled areas? Three Asian crane species models provide supporting evidence.

Species distribution models (SDMs) have become an essential tool in ecology, biogeography, evolution and, more recently, in conservation biology. How to generalize species distributions in large undersampled areas, especially with few samples, is a fundamental issue of SDMs. In order to explore this issue, we used the best available presence records for the Hooded Crane (Grus monacha, n = 33), White-naped Crane (Grus vipio, n = 40), and Black-necked Crane (Grus nigricollis, n = 75) in China as three case studies, employing four powerful and commonly used machine learning algorithms to map the breeding distributions of the three species: TreeNet (Stochastic Gradient Boosting, Boosted Regression Tree Model), Random Forest, CART (Classification and Regression Tree) and Maxent (Maximum Entropy Models). In addition, we developed an ensemble forecast by averaging predicted probability of the above four models results. Commonly used model performance metrics (Area under ROC (AUC) and true skill statistic (TSS)) were employed to evaluate model accuracy. The latest satellite tracking data and compiled literature data were used as two independent testing datasets to confront model predictions. We found Random Forest demonstrated the best performance for the most assessment method, provided a better model fit to the testing data, and achieved better species range maps for each crane species in undersampled areas. Random Forest has been generally available for more than 20 years and has been known to perform extremely well in ecological predictions. However, while increasingly on the rise, its potential is still widely underused in conservation, (spatial) ecological applications and for inference. Our results show that it informs ecological and biogeographical theories as well as being suitable for conservation applications, specifically when the study area is undersampled. This method helps to save model-selection time and effort, and allows robust and rapid assessments and decisions for efficient conservation.

Habitat preferences and conservation threats to Black-necked Cranes wintering in Bhutan.

Black-necked Crane (Grus nigricollis) is a vulnerable Red list species whose populations are declining. However, little is known about Black-necked Cranes' habitat requirements or the causes of their population decline. We identified Black-necked Cranes' winter roost and foraging preferences of Black-necked Cranes in Bhutan during the winter of 2013-2014. Black-necked Cranes' roosts were recorded using Garmin GPSmap 60CSx, while foraging preferences and threats to the birds were identified based on a survey of household heads (n = 107) residing within a 3 km radius of roost sites. We grouped the threats identified by the communities into four major categories, viz. biological, social, political and natural threats based on the relevance. Of the four major threats, communities residing within the roosting and foraging habitat of the Black-necked Crane reported biological threat as major. Biological threats as reported by communities include loss of habitat, food shortage and competition from other animals. We recommend the present roosting areas be designated as part of the conservation areas for Black-necked Crane wintering in Bumthang district. In addition to preserving these areas, government should also encourage farming in foraging habitats of Black-necked Crane, because they mainly feed on barley, wheat, paddy, potatoes and buckwheat, besides roots, tubers and insects in the wetlands.

Winter diet and food selection of the Black-necked Crane Grus nigricollis in Dashanbao, Yunnan, China.

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.