摘要: The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution. Avian brood parasitism reduces the reproductive success of hosts, and thus, hosts have evolved anti-parasitic strategies, such as rejecting parasitic eggs and adopting aggressive nest defense strategies, to avoid the cost brought on by brood parasitism. To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous, we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus), a host of the Common Cuckoo(Cuculus canorus). In the local area, the host Isabelline Shrike begins to breed in April, whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs. Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival, showing higher aggressiveness to cuckoo dummies, with no significant difference in attack rates among cuckoo, sparrowhawk and dove dummies, but their egg rejection did not change significantly. These results imply that Isabelline Shrikes may adjust their nest defense behavior, but not egg rejection behavior, with seasonality.

摘要: Shorebird populations are declining worldwide, mainly due to human disturbances and loss of coastal wetlands. However, supratidal habitats as saltpans could play a role in buffering human impact. Saltpans have shown to be important as feeding or breeding sites of some shorebird species. A potential conservation strategy to increase shorebird populations in saltpans is to manipulate the cues that birds use to select optimal breeding habitat. Here it is hypothesized that shorebirds are attracted to bivalve shells due to the advantages they offer. Following this hypothesis, we supplemented a restored saltpan in 2019 and 2021 with bivalve shells, expecting an increase in the number of breeding birds' nests. More than 75% of Kentish Plover(Charadrius alexandrinus) and Little Tern(Sternula albifrons) nests were found in patches with shells in both years. The best model for both species indicates that the presence of shells is the factor that most correlates with the location of nests. The probability of choosing one place over another to settle their nest increases in areas with an abundance of shells, double in the case of the Kentish Plover and triple in the case of the Little Tern. The result of this study may constitute a valuable tool for attracting birds to restored saltpans and could contribute to the success of expensive restoration projects where time is usually a constraint.

摘要: Animals must strike a balance between anti-predation behavior and other essential behaviors, such as foraging. Within the same species, strategies may vary on individuals' risk-taking preferences, and in this process the environment is a determinant, in addition to predator regime. The Crested Ibis(Nipponia nippon) exhibits such tendency. This is an endangered species, once inhabiting exclusively in China's Qinling Mountain. This used to be the sole remaining wild population. However, over recent decades, this population has expanded. A portion has relocated to breed in the lower plain area, which is characterized by elevated level of human activities and landscape complexity. We used flight initiation distance(FID) as an indicator of the ibises' risk-taking preference, particularly their response to human proximity. Additionally, we examined the environmental factors influencing their foraging site selection, including altitude, terrain openness, human activity intensity and human construction. Our findings revealed a significantly shorter FID among individuals relocating to plain habitats, indicating a higher tolerance of human proximity. The results showed that FID decreased with distance to the nearest human settlement. Another finding is that FID was independent of instant human activity intensity and environmental factors(altitude and terrain openness). These different may arise from various combinations of human activity, predation risk, and food abundance within the two habitats. These results provide insights into the in situ conservation of the threatened species within the context of global urbanization.

摘要: The analysis of bird ringing data often comes with some potential sources of error and bias, as ring wear and/or loss could affect mark-recapture analyses and produce erroneous estimates of survival. Furthermore, ring wear and loss rates may differ between and within species based on the habitat they use or the species' life-history traits and behaviour as well as the type of the ring. In this study we use resighting data from a long-term double marking experiment to directly estimate the rate of colour-ring loss among different Dalmatian Pelican colonies over time, evaluate any possible factors that could contribute to differential ring loss and assess how it may bias the results of mark-resighting analyses. Based on 14,849 resightings from 1275 individuals and using multi-state continuous-time hidden Markov models(HMMs) we showed that probability of ring loss was markedly different among colonies, ranging from 0.10 to 0.42 within the first year of marking, whereas the cumulative probability of losing a ring after ten years ranged 0.64 to 0.99. These rates are among the highest estimated when compared to previous studies in waterbirds. Our approach assessing the intra-specific variance in ring loss provided several factors potentially involved, such as the use of glue and the fledgling age accuracy and we could further hypothesise the effect of environmental factors. Finally, our results showed that ring loss can be a significant challenge for the assessment of the species' population dynamics using mark-recapture methods as survival was consistently underestimated when not accounting for ring loss and varied significantly among different colonies.

摘要: Weather conditions play a pivotal role in embryo development and parental incubation costs, potentially impacting the clutch size and incubation behavior of birds. Understanding these effects is crucial for bird conservation. Reeves' s Pheasant(Syrmaticus reevesii) is a threatened species endemic to China, which is characterized by female-only incubation. However, there is a lack of information regarding the impact of weather conditions on clutch size and incubation behavior in this species. Using satellite tracking, we tracked 27 wild female Reeves' s Pheasants from 2020 to 2023 in Hubei Province, China. We explored their clutch size and incubation behavior, as well as their responses to ambient temperature and precipitation. Clutch size averaged 7.75 ±1.36, had an association with average ambient temperature and average daily precipitation during the egglaying period, and was potentially linked to female breeding attempts. Throughout the incubation period, females took an average of 0.73 ±0.46 recesses every 24 h, with an average recess duration of 100.80 ±73.37 min and an average nest attendance of 92.98 ±5.27%. They showed a unimodal recess pattern in which nest departures peaked primarily between 13:00 and 16:00. Furthermore, females rarely left nests when daily precipitation was high. Recess duration and nest attendance were influenced by the interaction between daily mean ambient temperature and daily precipitation, as well as day of incubation. Additionally, there was a positive correlation between clutch size and recess duration. These results contribute valuable insights into the lifehistory features of this endangered species.

摘要: We examined habitat preferences and nesting requirements of sympatric populations of Middle Spotted Woodpecker(Dendrocoptes medius) and Syrian Woodpecker(Dendrocopos syriacus). We carried out our study in 2015–2018 in natural mountain forests of Southwest Iran. We compared selected features of nesting, territory, and outside territory tree stands of the studied woodpeckers. The Middle Spotted Woodpecker occupied only oak forests, but the Syrian Woodpecker inhabited heterogenic forests that included the preferred tree of this species, the Mount Atlas Mastic. We recorded that in the breeding territories of the Middle Spotted Woodpecker, a greater area covered by tree crowns, as well as a larger number of trees, and a larger trunk basal area were observed in comparison to the territories occupied by the more plastic Syrian Woodpecker. Different habitat preferences demonstrated by both species could be a result of the selection of tree stands that provide the necessary food resources for each woodpecker species. Adaptation of Syrian Woodpecker to use heterogenic forest stands including tree species that produce fruits and as Mount Atlas Mastic trees, which likely allowed this species to colonise in Asia and Europe non-forest tree stands as orchards or gardens. Our results showed that poor tree condition and large tree trunk dimensions had a positive impact on the selection of nesting sites by both species. The presence of trees with large trunk dimensions was associated with multiple years of use of woodpecker breeding sites in the studied forests. Maintaining habitats in suitable condition for both studied woodpeckers can be achieved by preserving natural forests in the mountain regions of Iran.

摘要: Sex-biased mortality can occur in birds during development, for example due to sexual differences in energy requirement and/or environmental sensitivity, or the effects of sex hormones or sex differences in the expression of mutations linked to sex chromosomes. The extent of sex-bias in mortality may also be related to environmental conditions that influence offspring development and survival. Urban areas often provide poorer conditions for nestling development resulting in higher offspring mortality compared to natural areas, which may accelerate sex differences in offspring mortality in cities. To test this hypothesis, we examined the sex ratio of dead offspring in Great Tits(Parus major), using 427 samples of unhatched eggs and dead nestlings collected in two urban and two forest sites between 2013 and 2019. The ratio of males in the whole sample of dead offspring(56.9%) was significantly higher than expected by an 1:1 ratio, and the strongest sex biases were detected in urban areas(57.6% males) and in young nestlings(<14 days old, 59.0% males). However, the sex ratios of dead offspring did not differ significantly among study sites and between offspring developmental stages. 29.3% of unhatched eggs contained a visible embryo, and the proportion of embryo-containing unhatched eggs did not differ significantly between urban and forest study sites. These results suggest male-biased offspring mortality in Great Tits, and highlight the need of large datasets to detect subtle differences between habitats and developmental stages.

摘要: Passerines moult during various life-cycle stages. Some of these moults involve the retention of a variable quantity of wing and tail feathers. This prompts the question whether these partial moults are just arrested complete moults or follow different processes. To address it, I investigated whether three relevant features remain constant across partial and complete moults: 1) moult sequence(order of activation) within feather tracts(e.g., consecutive outward moult of primaries) and among tracts(e.g., starting with marginal coverts, followed by greater coverts second, tertials, etc.); 2) dynamics of moult intensity(amount of feathers growing along the moult progress); and 3) protection of wing quills by overlapping fully grown feathers. To study the effect of moult completeness on these three features, I classified moults of 435 individuals from 61 species in 3 groups: i) complete and partial, ii) without and iii) with retention of feathers within tracts. To study the effect of life-cycle stage, I used postbreeding, postjuvenile, and prebreeding moults. I calculated phylogenetically corrected means to establish feather-moult sequence within tracts. I applied linear regression to analyse moult sequence among tracts, and polynomial regression to study the dynamics of moult intensity as moult progresses. Sequence and intensity dynamics of partial moults tended resemble those of the complete moult as moult completeness increased. Sequence within and among feather tracts tended to shift as moult intensity within tracts and number of tracts increased. Activation of primaries advanced in relation to the other feather tracts as number of moulted primaries increased. Tertial quills were protected by the innermost greater covert regardless of moult completeness. These findings suggest that moult is a self-organised process that adjusts to the degree of completeness of plumage renewal. However, protection of quills and differences among species and between postjuvenile-and prebreeding-moult sequences also suggest an active control linked to feather function, including protection and signalling.

摘要: Biological specimens are fundamental for taxonomy and flora/fauna research. More importantly, they also play crucial roles in recording environmental impacts on morphology and behavior, which is vital for biodiversity research and conservation. However, there are few systematic studies on the patterns and drivers of bird specimen number at regional scales. This study is the first attempt to examine the relationships between bird specimen number and species traits as well as climate niche breadth in China, aiming to answer two questions: 1) how do species' temperature niche breadth and precipitation niche breadth influence specimen number? 2) which trait is most associated with bird specimen number? The associations between bird specimen number and explanatory variables were examined using ordinary least squares, generalized linear models, phylogenetic generalized linear mixed models, and multiple comparisons. The results showed that Muscicapidae was the family with the highest specimen number, and Passeriformes was the order with the highest specimen number. Bird specimen number significantly increased with larger temperature niche breadth and precipitation niche breadth. Specimen number was also positively associated with geographic range size, habitat specificity, hunting vulnerability and clutch size, but negatively associated with body size. These findings suggest that future bird specimen collection should pay more attention to birds with limited ecological niches, large body sizes, and small clutch sizes. This research enhances the use of bird specimen data to study and preserve biodiversity.

摘要: Rivers are important habitats for wintering waterbirds. However, they are easily influenced by natural and human activities. An important approach for waterbirds to adapt to habitats is adjusting the activity time and energy expenditure allocation of diurnal behavior. The compensatory foraging hypothesis predicts that increased energy expenditure leads to longer foraging time, which in turn increases food intake and helps maintain a constant energy balance. However, it is unclear whether human-disturbed habitats result in increased energy expenditure related to safety or foraging. In this study, the scan sample method was used to observe the diurnal behavior of the wintering Spot-billed Duck(Anas poecilorhyncha) in two rivers in the Xin'an River Basin from October 2021 to March 2022. The allocation of time and energy expenditure for activity in both normal and disturbed environments was calculated. The results showed that foraging accounted for the highest percentage of time and energy expenditure. Additionally, foraging decreased in the disturbed environment than that in the normal environment. Resting behavior showed the opposite trend, while other behaviors were similar in both environments. The total diurnal energy expenditure of ducks in the disturbed environment was greater than that in the normal environment, with decreased foraging and resting time percentage and increased behaviors related to immediate safety(swimming and alert) and comfort. These results oppose the compensatory foraging hypothesis in favor of increased security. The optimal diurnal energy expenditure model included river width and water depth, which had a positive relationship; an increase in either of these two factors resulted in an increase in energy expenditure. This study provides a better understanding of energy allocation strategies underlying the superficial time allocation of wintering waterbirds according to environmental conditions. Exploring these changes can help understand the maximum fitness of wintering waterbirds in response to nature and human influences.