摘要: Urbanization induced by human activities presents both challenges and adaptive opportunities for wildlife. One notable impact of urban sprawl is the vast amount of waste it produces, which has discernible effects on wildlife.Interestingly, an emerging trend has been observed that birds are incorporating anthropogenic materials into their nests. However, the relationship between anthropogenic nesting materials(ANMs) and the reproductive performance of urban birds is unclear. In this study, we investigated the relationship between the incorporation of ANMs into nests and the reproductive performance of Chinese Bulbuls(Pycnonotus sinensis) by monitoring and collecting data on 136 breeding nests in Hangzhou, China. We gathered data on seven reproductive traits of Chinese Bulbuls, including laying date, incubation period, nestling period, clutch size, egg volume, hatching success rate, and fledging success rate. We then calculated the urbanization synthetic index as a measure of the level of urbanization and examined its relationship with the proportion and weight of ANMs. Through examination of nest components, we observed significant increase in the proportion and weight of ANMs with the urbanization synthetic index. Notably, we found a higher hatching success rate of Chinese Bulbuls with an increasing proportion of ANMs. However, the inclusion of ANMs in nests was not correlated with other reproductive traits of Chinese Bulbuls. Overall, the use of ANMs by Chinese Bulbuls is consistent with the adaptive hypothesis and the availability hypothesis. Further studies should use controlled experiments to investigate the impact of ANMs on avian reproductive success.

摘要: Although urbanization poses various threats to avifauna, some bird species, including Mallards(Anas platyrhynchos), choose towns and cities as their wintering habitats, possibly due to favourable temperatures and abundant anthropogenic food. In this study, we investigated how population dynamics changed in relation to winter harshness and intensity of supplementary bird feeding in Mallard, a dabbing duck species well adapted to an urban environment. We surveyed 15 city ponds for five consecutive years, counting overwintering individuals and incidents of bird feeding conducted by the citizens of Gdańsk. Number of Mallards observed in the studied area fluctuated both annually and within seasons, with on average 327(±SD =108.5) individuals and a malebiased sex ratio reported. We observed a gradient of feeding intensity on the surveyed ponds, with number of feeding incidents ranging from 0 to 30 in a day. The results indicated that the number of Mallards increased with the bird feeding intensity, independently of the size of the studied ponds, and both males and females were similarly attracted by food provisioning. More severe wintering conditions, expressed by the percentage of the ice cover of studied ponds resulted in more birds wintering in the urban area. This effect was more pronounced in females compared to males, possibly due to females having a lower ability to withstand severe wintering conditions, forcing them to relocate towards urban areas. Our results confirm that urbanized areas may serve as wintering grounds for birds, due to additional food resources available there and milder wintering conditions compared to surrounding rural areas.

摘要: Many bird species use social information to guide territory selection.Different species in different habitats may use both pre-breeding and post-breeding conspecific cues.Abandoned agricultural fields are of particular interest for studies of conspecific attraction because the ephemeral nature of the habitat suggests territory search just before breeding,but high predation pressure suggests the use of performance-based conspecific cues.We investigated whether post-breeding or pre-breeding social cues affect Whinchat(Saxicola rubetra) abundance at the territorial scale during a two-year experiment in abandoned fields.We assigned 27 experimental plots(3.14ha) to one of three treatments:post-breeding treatment,pre-breeding treatment and silent control.We conducted playback experiments with fledgling calls(evidence of past reproductive success) during the post-breeding period and male songs(evidence of conspecific presence) during the pre-breeding period.We estimated the difference in Whinchat abundance in two consecutive years and tested whether this value differed between treatment and control plots.We observed a slight increase(0.67 ± 0.29 pairs per plot) in Whinchat abundance in the post-breeding treatment plots and no significant changes in the pre-breeding(-0.22±0.32 pairs per plot)and control(-0.22±0.22 pairs per plot) plots.Our results suggest that Whinchats do not use conspecific acoustic cues during the pre-breeding period and provide limited evidence for the use of fledgling calls as conspecific cues in the post-breeding period.

摘要: Duck species are important vectors for seed dispersal of many plants, contributing significantly to the regeneration of wetland plant communities. However, research on the temporal changes in diet and the dynamics and differences of seed dispersal among different duck species is still limited. In this study, we analyzed the diversity of duck community and the diversity of seeds in the feces of different duck species from December to February for 2022–23 and 2023–24 in the coastal wetland of Dafeng, eastern Jiangsu Province, China. A total of 13 duck species were recorded in the four habitats, of which Spot-billed Ducks(Anas zonorhyncha) and Mallards(A. platyrhynchos) were the most abundant. The diversity and abundance of ducks vary across different habitats, and tidal flat supports the greatest diversity and abundance of ducks. We collected fecal samples from Spot-billed Ducks, Gadwalls(Mareca strepera), Mallards, and Eurasian Teals(A. crecca) in the tidal flat, from which seeds belonging to 7 families, 13 genera and 15 different plant species were obtained. There were significant differences in seed dispersal among the four duck species, which varied with the season. Gadwalls and Common Teals showed more significant diversity in seed dispersal, with their feces containing a greater variety of plant seeds, which is related to their broader dietary range and ecological adaptability. Furthermore, the seasonal variation in the number of seeds per feces reflected the availability of seeds in the habitat and the response of ducks to environmental changes, while variations in seed intake among different duck species may be associated with inter-annual weather condition changes. The results of this study will provide a new perspective for understanding the mechanisms of bird-mediated seed dispersal in coastal wetland and offer preliminary insights for the seed dispersal by Asian ducks.

摘要: Geese have undergone significant changes in their distribution and population size due to human-induced impacts. To improve our understanding of the two main geese populations in East Asia—Greater White-fronted(Anser albifrons; GWFG) and Bean Geese(Anser fabalis sensu lato; BEAG), which includes the Tundra A. f. serrirostris(TDBG) and Taiga Bean Geese A. f. middendorffii(TGBG), this study estimated their long-and short-term trends and the migration strategies based on their distribution during the migratory and wintering seasons, using nationwide census data collected over 24 years in South Korea. The TRIM(TRends and Indices for Monitoring data) analysis supported a robust long-term population increase since 1999, recently stabilizing around 150,000 individuals in GWFG and 100,000 in TDBG, respectively. But TGBG stabilized at around 7000 with no significant change of population over time. The shorter-term trends within a season suggested that wintering populations of GWFG and TDBG in China might stop over in Korea in their autumn migration before their sea-crossing, evidenced by the large congregation near the Yellow Sea coast followed by a gradual decrease. In contrast to autumn, there was no similar peak in spring migration, suggesting the potential for elliptical migration of some populations around the Yellow Sea. Our findings indicate a growing East Asian population and imply one of the migration strategies of the Greater White-fronted and Tundra Bean Geese. By collaborating with recent tracking data, long-term monitoring efforts could offer more detailed insights into population trends and migration strategies, thereby contributing to the effective management and conservation of goose species in East Asia.

摘要: In the co-evolutionary system of avian brood parasitism, egg recognition and rejection are common and generally act as effective anti-parasitic adaptations by hosts. Accordingly, most studies have examined the role of parasite egg colors and markings in detection cues in hosts; however, studies focusing on the effects of egg size and quantity are relatively scarce and have mostly concentrated on the hosts of parasitic cowbirds. Here, we studied the egg recognition behaviors of a potential host of the Common Cuckoo(Cuculus canorus)—the Green-backed Tit(Parus monticolus), to determine:(1) whether the host uses the sizes of parasite eggs and/or the quantity contrast between parasite and host eggs as cues for recognition,(2) whether the host employs the template or discordant recognition mechanism for egg recognition, and(3) whether the size and quantity of parasite eggs affect the egg rejection modes of the hosts. The results indicate that Green-backed Tits did not use parasite egg size as a primary cue for egg recognition. We hypothesized that both visual and tactile detection might be involved in egg recognition by Green-backed Tits and suggest further studies after controlling for nest light conditions. Differences in egg quantity between parasites and hosts were not used as cues for egg recognition because the hosts employed the template mechanism rather than discordance to recognize parasite eggs. However, both the relative sizes and quantity of parasite and host eggs significantly affected the rejection modes of parasite eggs, and larger or more parasite eggs triggered higher probabilities of nest desertion in hosts.

摘要: Avian extinctions have been relatively well documented in modern history, and in the past millennia, more bird species are known to have gone extinct than species in any other vertebrate class. We examined the biological correlates of extinction timing among 216 bird species that recently were either observed to go extinct or disappeared since 1500 CE, performing a novel analysis for examining the extinction trends of birds by modelling traits against the number of years since present day during which species have been extinct. We analyzed a broad range of traits and characteristics that have previously been associated with extinction and extinction risk in birds and compared the effects of these traits simultaneously against one another. In order to provide a more comprehensive and robust assessment of trait-based drivers of global bird loss in comparison to prior studies, we included extinct species recognized by any of the three major avian taxonomies as well as those birds that lack recent confirmed sightings and are at least functionally extinct. We found that insular, flightless, larger-bodied, ecologically specialized species, as well as those with high aspect ratio wings, were likely to go extinct earlier in time. Besides identifying the key locations and time periods over the past five centuries where birds have gone extinct, and highlighting specific extinction-prone taxonomic groups, we provide a complete and unified dataset of traits used in this study that helps address the lack of extensive public data on modern extinct species.

摘要: Insectivorous Palaearctic bird species associated with open habitats rely on high prey abundances, which are currently declining due to habitat loss and intensive agricultural practices. The European Bee-eater(Merops apiaster) is an opportunistic insectivore of open habitats, preying mainly on medium to large-sized flying insects.Its diet composition received some attention in the past, but the current variation in diet composition of birds breeding across different habitats, and between adults and chicks remains poorly known. In this study, we determine variation in bee-eaters' diet in colonies located in five common habitats at the Iberian Peninsula. We also assess differences in the diet composition of chicks and adults and investigate seasonal diet selectivity of adults. Finally, we explore the variability in the size of prey provided to chicks throughout their growth period.Hymenoptera and Coleoptera were the most important groups for bee-eaters, with adults and chicks consuming 58.8% and 64.1% of hymenopterans and 37.6% and 28.6% of coleopterans, respectively. The proportion of Hymenoptera(42.3–55.7%) and Coleoptera(43.3–53.5%) in the diet was similar in colonies in pasture and oak habitats, but Hymenoptera dominated(83.8% and 95.7%) in meadow and mixed forest colonies. Despite being a generally opportunistic predator, adult bee-eaters provide their progeny with an increasing proportion of larger insects through chick development. Moreover, they equally take Hymenoptera and Coleoptera for themselves and their chicks, even when the abundance of these insects decreases seasonally. Overall, these results suggest that local prey availability associated with specific habitats influences diet composition and that regional declines in certain groups may, therefore, affect insectivore species differently according to their dietary and habitat preferences.

摘要: The avian hippocampus, akin to its mammalian counterpart, plays a critical role in cognitive and physiological processes despite notable structural differences. Initially thought to be less developed, recent studies over the past two decades have revealed it as a complex brain region essential for diverse functions in both laboratory and free-living birds. This review synthesizes current knowledge on the avian hippocampus' organization, functionality, and neurophysiological significance. We first examine its anatomical structure and neuronal connectivity, comparing it with the mammalian hippocampus. We then highlight how its volume, neuronal density, and neurogenesis support spatial memory and navigation, influencing behaviors such as migration, food storing,brood parasitism, and homing. Beyond spatial functions, the avian hippocampus mediates emotion and stress physiology through interactions with the endocrine system, particularly via glucocorticoid receptors. It also influences spatial memory through sex hormones, especially estradiol, with local estrogen production through aromatase activity enhancing memory and plasticity. Therefore, the avian hippocampus serves as a central neural hub, integrating sensory information with internal states to facilitate essential behaviors and responses to external environmental stimuli. This review underscores the progress made in understanding this brain structure's roles, highlighting conserved neurophysiological functions across vertebrate taxa.

摘要: Endosymbiotic bacteria of insects can facilitate host expansion into novel niches by providing their host with a fitness benefit such as vitamins or amino acids that are otherwise lacking in their hosts' diet. This close association can lead to cospeciation between insects and their symbionts; however, the symbionts' small genome size leaves it susceptible to genome derogation which can result in symbiont replacement. Here, we screen chewing lice infesting shorebirds and terns to see what endosymbiotic bacteria are present, and build a summary phylogeny that includes louse endosymbiont sequences from this study as well as those from other louse genera, insects and bacteria strains from GenBank. We found a Sodalis-allied endosymbiont in Carduiceps, Lunaceps, Quadraceps, and Saemundssonia, as well as symbionts belonging to the family Enterobacteriaceae in Lunaceps, and Quadraceps. No louse species were host to both endosymbionts; however, the birds Kentish Plover(Charadrius alexandrinus) and Greater Crested Tern(Thalasseus bergii) were host to two genera of lice, each of which was infested with a different group of endosymbionts. In the summary phylogeny the endosymbionts from shorebirds, and tern lice did not form a monophyletic group, and therefore likely acquired their bacterial endosymbionts multiple times.