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

Genetic load and inbreeding are recognized as important factors to be considered in conservation programs. Elevated levels of both can increase the risk of population extinction by negatively impacting fitness-related characters in many species of plants and animals, including humans (inbreeding depression). Genomic techniques are increasingly used in measuring and understanding genetic load and inbreeding and their importance in evolution and conservation. We used whole genome resequencing data from two sibling grouse species in subarctic Eurasia to quantify both. We found a large range of inbreeding measured as F_ROH (fraction of runs of homozygosity) in individuals from different populations of Chinese Grouse (Tetrastes sewerzowi) and Hazel Grouse (T. bonasia). F_ROH estimated from genome-wide runs of homozygosity (ROH) ranged from 0.02 to 0.24 among Chinese Grouse populations and from 0.01 to 0.44 in Hazel Grouse. Individuals from a population of Chinese Grouse residing in the Qilian mountains and from the European populations of Hazel Grouse (including samples from Sweden, Germany and Northeast Poland) were the most inbred (F_ROH ranged from 0.10 to 0.23 and 0.11 to 0.44, respectively). These levels are comparable to other highly inbred populations of birds. Hazel Grouse from northern China and Chinese Grouse residing in the Qinghai-Tibetan Plateau showed relatively lower inbreeding levels. Comparisons of the ratio between deleterious missense mutations and synonymous mutations revealed higher levels in Chinese Grouse as compared to Hazel Grouse. These results are possibly explained by higher fixation rates, mutational melt down, in the range-restricted Chinese Grouse compared to the wide-ranging Hazel Grouse. However, when we compared the relatively more severe class of loss-of-function mutations, Hazel Grouse had slightly higher levels than Chinese Grouse, a result which may indicate that purifying selection (purging) has been more efficient in Chinese Grouse on this class of mutations.

Extra-pair copulation (EPC) can potentially maximize individual reproductive fitness, and this process may involve sexual selection of male and female traits that reflect individual quality. Previous studies have implied that adult characteristics are associated with the probability of extra-pair paternity (EPP), but it differs between species. Moreover, there are relatively few examples of the adaptive rationale for females’ engagement in EPCs based on an examination of these more traditionally recorded traits, in combination with female flight-mediated traits such as wing length. We investigated whether EPP existed in the wild Chestnut Thrush (Turdus rubrocanus) population during three breeding seasons (2019–2021), and whether paternity was related to morphological traits of males and females. Eight highly variable microsatellite loci were used to identify paternity, and generalized linear mixed models were used to analyze the relationship between paternity and morphological traits. We found that EPP existed in the Chestnut Thrush. 53.3% (N ​= ​41/77) of the broods contained at least one extra-pair offspring (EPO), and 34.6% (N ​= ​72/208) of the nestlings were EPO. We also found that male wing length was negatively associated with the probability of EPP and the proportion of EPO. Female body length was positively related to the probability of EPP. Both female body condition and mass were negatively associated with the proportion of EPO. While other traits of male and female did not relate to the probability of EPP or the proportion of EPO. Extra-pair males had better body condition compared to the males they cuckolded. EPO did not differ from their half-siblings in terms of body size or body condition. The results suggest that body size and body condition were associated with EPP in the Chestnut Thrush. This study provides fundamental information for further studies on the evolution and maintenance of EPP in the Chestnut Thrush, and it is also useful for the comparison of EPP among Turdus species.

Thermogenic features are often invoked to illustrate animal's colonization, distribution, and response to climate change. To understand why the White-browed Laughingthrush (Pterorhinus sannio) has expanded its distribution to temperate zones in recent years, we compared its thermogenic features with three species of songbirds that co-occur in its newly colonized areas. Thermogenic parameters of these four species were measured under different ambient temperatures, ranging from 0 to 40 ​℃. The results showed that basal metabolic rate (BMR) was 44.5 ​± ​3.9 ​mL O₂/h in P. sannio, which is lower than predicted value by its body weight. This is also lower than the BMR of both its temperate congener the Plain Laughingthrush (P. davidi) and the montane, similar species Elliot's Laughingthrush (Trochalopteron elliotii). The thermal neutral zone (TNZ) in P. sannio was 15–35 ​℃, as compared to 10–27.5 ​℃ in P. davidi, 25–30 ​℃ in T. elliotii, and 7.5–32.5 ​℃ in the Green-capped Greenfinch (Chloris sinica). Thermal conductance was lowest in P. sannio, with the minimum value lower than the predicted value based on its body weight. Our results showed that the northward-colonizing P. sannio exhibited different thermogenic characteristics compared with its coexisting species in the new habitat, even its congener P. davidi, which shared similar microhabitats to P. sannio. We suggest that researchers further explore the physiological mechanisms of birds' northward expansion.

Sex differences in plumage color are common in bird species. Some bird species are regarded as sexually monochromatic in human visual systems, and in recent years, some species are found to be of cryptic (to human) sexual dichromatism by spectrophotometric techniques. However, the functions of plumage color are still less understood in these species. Here, we focused on plumage color traits in the Chestnut Thrush (Turdus rubrocanus), which is considered as a sexually monochromatic bird by human observers. We used spectrometer analyses and avian visual modeling to investigate the color traits of males and females, and whether these color traits are involved in assortative mating. We found that Chestnut Thrush showed sexual dichromatism in bill, throat and wing, and pairs mated assortatively with colorations of throat, chest, crown and wing. We also found that color of tarsus was different between two consecutive years. These results revealed that Chestnut Thrush is sexually dichromatic in the avian visual system, and plumage color traits play important roles in mate choice.

Global climate change has a significant effect on species, as environment conditions change, causing many species' distributions to shift. During the last three million years, the earth has experienced glacial oscillations, forcing some species to survive in ice-free refugia during glacial periods and then disperse postglacially. In this study, by assessing the potential distribution of Siberian Grouse (Falcipennis falcipennis), we used Global Circular Models and Representative Concentration Pathways to model their pattern of range changes during glacial oscillations and the potential impact of present global warming. We used 158 location records of Siberian Grouse to generate a full climate model using 19 bioclimate variables in MaxEnt. We discarded variables with a correlation coefficient larger than 0.8 and relatively lower modeling contributions between each pair of correlated variables. Using the remaining variables, we created a normally uncorrelated simple climate model to predict the possible distribution of Siberian Grouse from the most recent Ice Age to present and to 2070. Then we added geographical data and the human interference index to construct a multiple factor full model to evaluate which were important in explaining the distribution of Siberian Grouse. The Total Suitability Zone (P ​≥ ​0.33) of Siberian Grouse is about 243,000 ​km² and the Maximum Suitability Zone (P ​≥ ​0.66) is 36,000 ​km² and is confined to the Russian Far East. Potential habitat modeling suggested that annual precipitation, annual mean temperature, and the distance from lakes are the most explanatory variables for the current distribution of Siberian Grouse. The distribution center moved to the southeast during the Last Glacial Maximum and spread back to the northwest after the ice melted and temperatures rose. The total area range of Siberian Grouse experienced a dramatic loss during the Last Glacial Maximum. Global warming is presently forcing the Siberian Grouse to migrate northward with a contraction of its range. There is an urgent need to protect its habitat, because little of its Maximum Sustainable Zone is protected, although there are some large reserves in that area.