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Host-associated microbiotas are known to influence host health by aiding digestion, metabolism, nutrition, physiology, immune function, and pathogen resistance. Although an increasing number of studies have investigated the avian microbiome, there is a lack of research on the gut microbiotas of wild birds, especially endangered pheasants. Owing to the difficulty of characterizing the dynamics of dietary composition, especially in omnivores, how the gut microbiotas of birds respond to seasonal dietary changes remains poorly understood. The Sichuan partridge (Arborophila rufipectus) is an endangered pheasant species with a small population endemic to the mountains of southwest China. Here, 16S rRNA sequencing and Tax4Fun were used to characterize and compare community structure and functions of the gut microbiota in the Sichuan partridges across three critical periods of their annual life cycle (breeding, postbreeding wandering, and overwintering). We found that the microbial communities were dominated by Firmicutes, Proteobacteria, Actinobacteria, and Cyanobacteria throughout the year. Diversity of the gut microbiotas was highest during postbreeding wandering and lowest during the overwintering periods. Seasonal dietary changes and reassembly of the gut microbial community occurred consistently. Composition, diversity, and functions of the gut microbiota exhibited diet-associated variations, which might facilitate host adaptation to diverse diets in response to environmental shifts. Moreover, 28 potential pathogenic genera were detected, and their composition differed significantly between the three periods. Investigation of the wild bird gut microbiota dynamics has enhanced our understanding of diet-microbiota associations over the annual life cycle of birds, aiding in the integrative conservation of this endangered bird. IMPORTANCE Characterizing the gut microbiotas of wild birds across seasons will shed light on their annual life cycle. Due to sampling difficulties and the lack of detailed dietary information, studies on how the gut microbiota adapts to seasonal dietary changes of wild birds are scarce. Based on more detailed dietary composition, we found a seasonal reshaping pattern of the gut microbiota of Sichuan partridges corresponding to their seasonal dietary changes. The variation in diet and gut microbiota potentially facilitated the diversity of dietary niches of this endangered pheasant, revealing a seasonal diet-microbiota association across the three periods of the annual cycle. In addition, identifying a variety of potentially pathogenic bacterial genera aids in managing the health and improving survival of Sichuan partridges. Incorporation of microbiome research in the conservation of endangered species contributes to our comprehensive understanding the diet-host-microbiota relationship in wild birds and refinement of conservation practices. [ABSTRACT FROM AUTHOR]

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

Brood parasites and predators pose different threats to passerines that may favour the evolution of enemy-specific defence strategies. Furthermore, potential sex-specific variation in parental investment may be manifested in differences between male and female nest defence behaviour. We investigated these hypotheses in Oriental reed warblers (Acrocephalus orientalis), by recording sex- and stage-specific (nests with eggs or nestlings) responses to stuffed dummies placed at their nests. Warblers showed the highest level of aggression to the co-occurring parasite, the common cuckoo (Cuculus canorus), colour morph (grey), but showed reluctance to mob or attack the cooccurring nest predator, the magpie (Pica pica). There was a sex difference in rate of body attacks towards rufous morph common cuckoo, sparrowhawk (Accipiter nisus) (locally absent parasite and predator, respectively) and the spotted dove (Streptopelia chinensis) (locally present, harmless species), with females showing better ability to distinguish between these species than males. [ABSTRACT FROM AUTHOR]

Correct assessment of species limits and phylogenetic relationships is a prerequisite for studies in ecology and evolution. Even in well-studied groups such as birds, species delimitation often remains controversial. Traditional avian taxonomy is usually based on morphology, which might be misleading because of the contingent nature of evolutionary diversification. The sand plover complex (genus Charadrius) may be such an example wherein 2 Lesser Sand Plover C. mongolus subspecies groups have been proposed to comprise 2 species. We use genome-wide data of 765K SNPs to show that the widely accepted taxonomic treatment of this sand plover complex appears to be a paraphyletic grouping, with two Lesser Sand Plover subspecies groups found not to be each other's closest relatives, and with the mongolus subspecies group being the sister taxon of Greater Sand Plover C. leschenaultii. Based on genomic and acoustic analyses, we propose a three-way split of the Sand Plover complex into the Siberian Sand Plover C. mongolus,Tibetan Sand Plover C. atrifrons, and Greater Sand Plover C. leschenaultii.The similar sizes of the Siberian and Tibetan Sand plovers may be the result of niche conservatism coupled with rapid morphological and ecological differentiation in the Greater Sand Plover. Gene flow between the non-sister Tibetan and Greater Sand plovers might have happened in phases of secondary contact as a consequence of climate-driven range expansions. We call for further studies of the Sand Plover complex, and suggest that speciation with intermittent gene flow is more common in birds than currently acknowledged. [ABSTRACT FROM AUTHOR]

Background: The Emei Shan Liocichla (Liocichla omeiensis) is an endemic bird species to southwestern China with a small geographic range. However, little was known about the genetic status of this threatened species. Methods: We applied restriction-site-associated DNA sequencing (RAD-Seq) for rapid mass identification of microsatellite markers of the Emei Shan Liocichla. Results: A total of 11,564 microsatellite sequences were obtained, 600 random loci were designed for screening and 24 polymorphic microsatellite loci were selected for further validation. The average allele number, average observed heterozygosity and average expected heterozygosity were relatively low in our samples, which were 6.08, 0.6618 and 0.7048, respectively, indicating that the Emei Shan Liocichla might have lost some genetic diversity. Further analyses suggested that the populations distributed on two mountains (Daxiangling and Xiaoliangshan) showed a modest degree of genetic differentiation. Conclusions: These novel microsatellite markers provided valuable preliminary knowledge regarding the genetic status of the Emei Shan Liocichla and can be useful in further studies, as well as in the management and conservation of this species. [ABSTRACT FROM AUTHOR]

Background: The success of cuckoo parasitism is thought to depend largely on the extent of egg matching between cuckoo and host eggs, since poor-matching cuckoo egg would lead to more frequent egg rejection by the host. In this study, we investigated how egg-spot matching between the Common Cuckoo (Cuculus canorus) and its host, the Oriental Reed Warbler (Acrocephalus orientalis) is affected by the local parasitism rate, nest availability in breeding synchronization and egg rejection. Methods: We used the paired design of parasitized and their nearest non-parasitized nests where breeding occurred simultaneously to compare egg-spot matching. The image analysis was used to compare four eggshell pattern variables, namely spot size, density, coverage on the different areas of egg surface, and the distribution on the whole egg surface. Egg recognition experiments were conducted to test the effect of egg spots on egg rejection by the host. Results: Our results show that much better matching in almost all spot parameters tested on the side of the egg and the spot distribution on the whole egg occurred in parasitized nests than in non-parasitized nests. Matching of spot density between cuckoo and host eggs in parasitized nests increased with the synchronization between temporal availability of nests and the egg-laying period of female cuckoos. Egg recognition experiments in which the warbler eggs were deliberately painted with extra spots led to a significantly higher egg rejection rate (78.3%) than of unpainted eggs. Conclusion: Our data suggest that both the high temporal encounter rate between cuckoo and warbler nests as well as the high egg rejection ability of the host are important factors for egg-spot matching of the cuckoos. [ABSTRACT FROM AUTHOR]

Background: The Emei Shan Liocichla (Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success. Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates (DSR). Nest success was calculated using the Mayfield method. Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091 (95 % CI 0.9346–0.9711) (n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels (n = 5), snakes (n = 3), raptors (n = 1) and wasps (n = 1). We found that: (1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla, (2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and (3) the nest-site-selection variables we measured appeared not to be positively associated with nest success. Conclusions: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species. [ABSTRACT FROM AUTHOR]

Individuals that retain their former partners often perform better than conspecifics that switch partners. This may be due to high-quality individuals being more faithful to their partners and more productive. Investigations of the fitness benefits of mate retention that also control for potential confounding effects of individuals are scarce. We studied the influence of mate retention and breeding experience on breeding performance of the hair-crested drongo (Dicrurus hottentottus) by carrying out both cross-sectional and longitudinal analyses. Pairs with longer pair-bond duration did not fledge more young or fledglings of better body condition nor did they produce more or better fledglings than newly formed pairs consisting of at least 1 experienced breeder, that is, individuals that had bred before. Individuals produced fewer fledglings when they were paired with an inexperienced breeder, especially when females were paired with inexperienced males. Although clutch size was not affected by mate retention or breeding experience, pairs consisting of inexperienced breeder(s) had a relatively higher predation rate of eggs and/or nestlings because they may be less effective in nest defense. The onset of breeding was advanced in the year following mate retention, but not in the second year thereafter, when pairs still remained together. Furthermore, only the breeding experience of the male determined the onset of breeding: Pairs consisting of inexperienced males bred later in the season. Our results suggest that breeding experience, and particularly the breeding experience of the male, but not mate retention, is important in determining the breeding performance of hair-crested drongos. [ABSTRACT FROM AUTHOR]

Background: The Hair-crested Drongo (Dicrurus hottentottus) exhibits a unique nest-dismantling behavior after the fledging of the young. One hypothesis explaining this behavior is dismantling one's own nest may reduce potential competition for nest sites in the following breeding season because suitable breeding habitat might be limited, and sites are often reused. Methods: By comparing the habitat features at nest and random locations, we determined the nest habitat preference of the Hair-crested Drongo within Dongzhai National Nature Reserve, Henan, China. We also compared habitat features with nesting success to determine if any trends could be detected. Results: We found that nest tree height, diameter at breast height, live crown ratio, tree rank, and presence of overstory were significantly higher at nesting locations than random locations; slope, leaf litter cover percentage and depth, presence of understory and midstory, and number of trees per hectare were significantly lower at nest sites than random sites. Drongos preferred to use some tree species, such as Metasequoia glyptostroboides, Castanea mollissima, and Pterocarya stenoptera for nesting. Failed nests were often associated with habitat with higher percentage of leaf litter on the ground. Conclusion: Our data support that selection of nest sites does occur for this species at this site and therefore support the hypothesis that breeding habitat limitation could be one of the driving forces for the development of the nestdismantling behavior in this species. [ABSTRACT FROM AUTHOR]

The taxonomic status of subspecies has long been debated, especially in conservation biology. Some proposed subspecies must be evolutionarily distinct to be considered conservation units. White-necklaced Partridge (Arborophila gingica) comprises two subspecies, A. g. gingica and A. g. guangxiensis. A. g. guangxiensis, restricted to three isolated small areas in Guangxi, China, with limited population sizes, is a newly discovered subspecies based on recently identified geographic and phenotypic differences between A. g. gingica; however, evidence is lacking that can effectively identify whether the subspecies is evolutionarily distinct. Here, three mitochondrial DNA segments and four nuclear introns were used to test whether the two subspecies are reciprocally monophyletic, which has been proposed as an objective method to evaluate evolutionary distinctiveness. The results indicate that the two subspecies are genetically divergent and form reciprocal monophyletic groups. Therefore, this study further supports the taxonomic validity and distinctiveness of A. g. guangxiensis and suggests that this subspecies be considered as a conservation unit. [ABSTRACT FROM AUTHOR]

Understanding the historical dynamics of animal species is critical for accurate prediction of their response to climate changes. During the late Quaternary period, Southeast Asia had a larger land area than today due to lower sea levels, and its terrestrial landscape was covered by extensive forests and savanna. To date, however, the distribution fluctuation of vegetation and its impacts on genetic structure and demographic history of local animals during the Last Glacial Maximum (LGM) are still disputed. In addition, the responses of animal species on Hainan Island, located in northern Southeast Asia, to climate changes during the LGM are poorly understood. Here, we combined phylogeographic analysis, paleoclimatic evidence, and species distribution models to examine the response of the flightless Hainan Partridge (Arborophila ardens) to climate change. We concluded that A. ardens survived through LGM climate changes, and its current distribution on Hainan Island was its in situ refuge. Range model results indicated that A. ardens once covered a much larger area than its current distribution. Demographic history described a relatively stable pattern during and following the LGM. In addition, weak population genetic structure suggests a role in promoting gene flow between populations with climate-induced elevation shifts. Human activities must be considered in conservation planning due to their impact on fragmented habitats. These first combined data for Hainan Partridge demonstrate the value of paired genetic and SDMs study. More related works that might deepen our understanding of the responses of the species in Southeast Asia to late Quaternary Climate are needed. [ABSTRACT FROM AUTHOR]

Although a number of studies have assessed the effects of geological and climatic changes on species distributions in East Asian, we still have limited knowledge of how these changes have impacted avian species in south-western and southern China. Here, we aim to study paleo-climatic effects on an East Asian bird, two subspecies of black-throated tit (A. c. talifuensis-concinnus) with the combined analysis of phylogeography and Ecological Niche Models (ENMs). We sequenced three mitochondrial DNA markers from 32 populations (203 individuals) and used phylogenetic inferences to reconstruct the intra-specific relationships among haplotypes. Population genetic analyses were undertaken to gain insight into the demographic history of these populations. We used ENMs to predict the distribution of target species during three periods; last inter-glacial (LIG), last glacial maximum (LGM) and present. We found three highly supported, monophyletic MtDNA lineages and different historical demography among lineages in A. c. talifuensis-concinnus. These lineages formed a narrowly circumscribed intra-specific contact zone. The estimated times of lineage divergences were about 2.4 Ma and 0.32 Ma respectively. ENMs predictions were similar between present and LGM but substantially reduced during LIG. ENMs reconstructions and molecular dating suggest that Pleistocene climate changes had triggered and shaped the genetic structure of black-throated tit. Interestingly, in contrast to profound impacts of other glacial cycles, ENMs and phylogeographic analysis suggest that LGM had limited effect on these two subspecies. ENMs also suggest that Pleistocene climatic oscillations enabled the formation of the contact zone and thus support the refuge theory. [ABSTRACT FROM AUTHOR]

The article reports on the study of nest-dismantling behavior of the hair-crested drongo in China in 2007. According to the study, 12 out of 13 nests that fledged young were dismantled by the adults. It indicates that some individuals started dismantling behavior on the time the young birds left the nest and completed dismantling within how many days, while others waited several days and took longer to finish. The author believes that Hair-crested Drongo's nest-dismantling is an adaptive behavior to increase fitness by reducing risk of future predation and competition for nest sites.

Disabled homolog 2 ( Drosophila) interacting protein (DAB2IP/Dab2IP) is a member of the GTPase-activating protein for downregulating the Ras-mediated signal pathway and TNF-mediated apoptosis. The downregulation of human DAB2IP mRNA levels was detected in prostate cancer cells due to the epigenetic regulation. Here, we isolated a mouse Dab2ip gene with a highly homologous sequence to that of the human and rat gene and mapped it at chromosome 2B. The mDab2ip gene contains 14 exons and 13 introns and spans approximately 65 kb. Exon1 contains at least three splicing variants (Ia, Ib, and Ic). The deduced amino acid sequence of mouse Dab2IP encompasses 1065 residues containing several unique protein interaction motifs as well as a Ras-like GAP-related domain, which shares a high homology with both humans and rats. Data from real-time RT-PCR analysis revealed a diverse expression pattern of the mDab2ip gene in various organs, implying differential regulation of this gene from various tissues. We have mapped a 1.3-kb segment containing a 5′-upstream region from exon Ia as a promoter region (–147/+545) in prostatic epithelial cell lines (TRAMP-C); this region is highly GC-rich, and mDab2ip appears to be a TATA-less promoter. It appears that epigenetic regulation, particularly histone acetylation of the Dab2ip gene promoter, plays an important role in modulating its gene expression in the mouse prostate cancer cell. [ABSTRACT FROM AUTHOR]

The article presents research on the effects to the Chinese ecosystem of the construction of seawalls along Chinese coastal wetlands and offers evidence suggesting that their construction will threaten biodiversity and ecosystem services. Topics include the importance of coastal wetlands in China, causes for the loss of the wetlands including government policy and economic growth, and policy recommendations for maintaining minimum coastal wetlands areas.