摘要: Roads are a leading cause of habitat fragmentation and may reduce bird populations by increasing nest predation rates. However, few studies have investigated the effects of traffic volume on the reproductive success of roadside birds in the neotropics. Our goal was to evaluate the effects of spatial, temporal, and vehicle flow variations on the survival of artificial open-cup nests. The study was carried out in a nature reserve on the side of a highway during the breeding season(from October to March) in two restinga(sand-coastal plain) phytophysiognomies in southeastern Brazil: non-floodable(open) and floodable(closed). One hundred thirty nests were distributed along transects ranging from 3 m to 300 m from the highway in each vegetation type(totaling 260 nests). The nests were checked every three days for their status(depredated or intact) over 12 days, and new nests were subsequently placed near sampling points of depredated or successful nests. We estimated survival using logistic exposure generalized linear and additive mixed models. At the end of the 180 days of the experiment, 33% of 6202 nests were successful. Nest survival was higher in open restinga than in closed restinga. In both habitats, nest survival was lowest mid-season and highest at the beginning and end. Survival rates peaked near the highway, declined up to 50 m away, then showed a slight increase. Finally, survival increased at moderate-tohigh traffic volumes(～22,000 vehicles/day), particularly in open restinga. We suggest that spatial, temporal, and habitat-specific highway impacts(e.g., noise, vibration, visual stimuli) can lead to variations in the activity of nest predators, generating fluctuations in nest survival associated with predator behavior.

摘要: The factors affecting the behavior of non-specialized nectar-feeding passerines have received little attention in the literature on plant-pollinator interactions. Puya chilensis(Bromeliaceae) has sterile branch apices that project outward from the inflorescence. In this study, we evaluate the functional role of sterile apices as support systems for bird foraging behavior. We recorded bird visitation and flower probing in the presence and absence of sterile branches during the spring seasons of 2021 and 2024. The results revealed that experimental plants with excised branches received fewer bird visits and flower probings than control plants, indicating that sterile branches play an important role in the nectar-feeding behavior of passerine birds in P. chilensis.

摘要: With the ongoing acceleration of global urbanization, an increasingly larger proportion of natural habitats are being transformed and utilized by humans. Urbanization has a substantial impact on animal populations, exposing them to greater risks, but also presenting new opportunities and resources. Although the effects of urbanization and brood parasitism on the population dynamics and behavior of host birds have received considerable attention, there has been comparatively little research on how urbanization might affect the risk of brood parasitism on host birds. From April to August in 2023 and 2024, we investigated the risk of brood parasitism on Azure-winged Magpies(Cyanopica cyanus) breeding in the urban center, outskirt, and rural areas of Wuhan City, Hubei Province, China. The results revealed significant differences in the risk of brood parasitism among Azure-winged Magpies in the three regions, with the proportion of magpies parasitized by the Asian Koel(Eudynamys scolopaceus) being found to be significantly lower in the city center(0%) than that in outskirt(3.8%) and rural(11.4%) areas. Our results are consistent with the idea that cities can act as refuges that reduce the risk of brood parasitism experienced by host Azure-winged Magpies. Accordingly, breeding in cities enables Azurewinged Magpies to escape brood parasitism by the Asian Koel.

摘要: Avian incubation is characterised by the contact between the eggs and the bird's skin to transfer heat to increase egg temperature above ambient conditions. Birds can be attentive to the clutch all of the time or, particularly if only one parent incubates, attentiveness may be quite low. Attentiveness is related to egg size with large eggs having high attentiveness, whereas small eggs(<10 g) can have attentiveness ranging from 50% to 100%. Previous studies have suggested that incubation duration is a function of attentiveness albeit for small birds. This study tested the hypothesis that, after controlling for egg size and phylogeny, incubation duration would be a function of attentiveness. Data for 444 bird species representing 24 orders were analysed. Whilst egg mass had a significant relationship with incubation duration, there was no relationship with attentiveness for all of the species or a subset of the passerines. Despite egg temperature drops during an incubation recess, average daytime and night-time temperatures are similar in a range of species. Re-examination of previously reported temperature profiles recorded by dummy eggs over a 24-h period shows that after an incubation recess there seems to be an additional heat flux that raises egg temperature above that seen during night-time periods of constant incubation. The reasons why eggs under intermittent incubation are not considerably cooler than eggs during constant incubation are discussed.

摘要: Understanding how diet influences the breeding success of Saker Falcons(Falco cherrug) is key to assessing the role of food supply in population dynamics and informing conservation strategies. Through pellet analysis, we evaluated the influence of small mammal prey—present in 95% of pellets—on the reproductive performance of the sakers. In Mongolia, three species comprised 95% of the identified small mammals: Mongolian Gerbil(Meriones unguiculatus, 39%), Brandt's Vole(Lasiopodomys brandtii, 49%) and Daurian Pika(Ochotona dauurica, 7%). We found a strong positive association between the proportion of small mammals in the diet and key breeding parameters of sakers. Clutch size, fledged brood sizes, and nest success all increased with a mammalrich diet. Earlier laying was also linked to higher small mammal intake and was independently associated with improved breeding outcomes. These findings highlight a critical role of small mammal prey in shaping the reproductive success of sakers. Conserving and restoring grassland habitats that support abundant prey populations is essential for sustaining saker populations and achieving long-term conservation goals.

摘要: Habitat fragmentation poses a significant threat to bird communities, especially those in open and semi-open ecosystems such as steppes. This study investigates how steppe birds adapt to and utilize fragmented habitats by combining niche modeling with ecological trait analysis. We conducted standardized point surveys to examine the habitat preferences of 32 bird species in Inner Mongolia, China, and quantified their habitat niche parameters using the Outlying Mean Index(OMI). Our results reveal distinct habitat preferences among species, with some thriving in intact environments while others are better adapted to fragmented areas. Grassland species showed high specialization along the fragmentation gradient, while others exhibited adaptability to varying levels of fragmentation. Using a Generalized Additive Model(GAM), we identified three key traits influencing habitat occupancy: hand-wing index, body mass, and range size. Specifically, species with medium hand-wing indices, moderate body mass, and larger range sizes were more likely to occupy heavily fragmented habitats. These findings provide empirical evidence on how habitat fragmentation affects bird species in steppe ecosystems. The study highlights the importance of functional traits in understanding avian responses to habitat fragmentation and offers a foundation for developing effective conservation strategies to preserve biodiversity in fragmented landscapes.

摘要: The post-fledging period, extending from fledging to independence, is a crucial life stage characterized by high mortality due to fledglings' limited mobility and inexperience. During this stage, fledglings gradually increase their mobility, leave their parents, disperse from their natal site, and respond to the challenges of new environments. Characterizing these post-fledging movements and space use is essential for understanding juvenile survival strategies and devising targeted conservation measures. The Crested Ibis（Nipponia nippon）, an endangered species and a highly protected animals at the national level in China, has seen limited research on its postfledging movements and space use. From 2015 to 2023, we utilized biologgers, combined with field surveys, to study the movement and space use characteristics of 37 fledglings in Hanzhong City, Shaanxi Province, China, over a two-month post-fledging period. We quantified changes in activity levels（based on overall dynamic body acceleration）, independence timing, onset of post-fledging dispersal, habitat selection, and daily activity rhythms after independence. Our results revealed individuals began independent living 26.23 ±2.34 days post-fledging and onset of dispersal at 25.58 ±2.33 days, with a range area at the natal of 2.08 ±0.56 km². The initial 30 days post-fledging are characterized as an ontogenetic phase marked by a rapid increase in body activity level. Fledglings preferred paddy fields during the independent period rather than the forests they relied on before independence. Interestingly, the daily activity rhythm, particularly foraging behavior, peaked at noon—contrasting with the expected morning and evening activity peaks—likely as an adaptation to avoid periods of peak human activity. Additionally, drowning, collisions, and predation in paddy fields are noteworthy causes of fledgling mortality. Consequently, we recommend protecting a 2-km² area around the nest site for at least two-month post-fledging, implementing safety measures around power lines and cesspools. Additionally, reducing human disturbances near foraging habitats and expanding space within paddy fields would help mitigate survival pressures on fledglings.

摘要: Studying coexistence mechanisms is practically important for understanding and conserving marine biodiversity and community structure. Tropical marine ecosystems may exhibit higher competition between top predators due to generally low primary productivity and pronounced seasonal fluctuation in food availability. Consequentially, niche segregation in sympatric breeding seabirds is expected to occur as a mechanism to maintain species coexistence. However, a single-dimensional study on seabird niche segregation might result in unclear niche overlap. Here, we investigated multi-dimensional niche segregation of tropical seabirds during field expeditions to the Xisha Archipelago, China, in 2023. We reconfirmed the breeding status of six species of terns and noddy, and further revealed the multi-dimensional niche segregation among Black-naped(Sterna sumatrana), Bridled(Onychoprion anaethetus) and Roseate(Sterna dougallii) Terns. Spatially, these three species utilized nest sites that differentiated by vegetation and distance to sea. Temporally, Black-naped Terns bred earlier and for a longer period, while Bridled and Roseate Terns had more restricted breeding seasons. Furthermore, the daily foraging activity patterns of these species also differed, with Bridled Terns potentially having a longer foraging time at noon. In terms of diet, Bridled Terns were opportunists that fed on fishes, squids and insects, such as migratory fruit-piercing moths, while Roseate Terns were primarily piscivorous, especially feeding on Exocoetidae(flying fishes). Seabirds play a crucial role in marine ecosystems and are globally threatened. Our findings shed light on the complex mechanisms facilitating the coexistence of sympatric seabird species in China. Further research is needed to examine other ecological interactions and to develop effective conservation strategies for protecting these valuable seabird populations.

摘要: A playback experiment is a well-established method for behavior research, especially in the study of the territorial responses of songbirds. Birds obtain information from multimodal signals, whereas only acoustic signals are provided in traditional playbacks. Many efforts have been made to combine visual signals with playback experiments, e.g., static specimens, videos, live birds and robotic models. Multimodal signal playback provides an elaborate way to study the behavior of focal birds. Although combining visual signals with playback experiments can elicit more authentic responses, empirical evidence remains scarce. In this study, a robot model mimicking a territory intruder was presented to Eurasian Nuthatch(Sitta europaea) to evaluate its effect on playback experiments. The experiments were conducted on 45 individuals during the 2021 breeding season in Baihua Mountain National Nature Reserve(39°83'N, 115°58'E), China. These 45 individuals were randomly divided into three equal-sized groups corresponding to the experimental treatments: playback sound only; sound with a static model; and sound with a dynamic model. Behavioral variables were recorded during each experiment to generate response intensity via principal component analysis. The results revealed that there was no significant difference in response intensity among the three different experimental treatments. Considering the dense habitat where nuthatches live, the robot model may have insufficiently increased the stimulation of sensory perception. We propose that the effect of visual signals during playback should be evaluated in more species and that behavioral studies could be conducted using multimodal signals to provide a more realistic representation of bird-bird interactions.

摘要: Avian alarm calls mediate defenses against brood parasites and predators. These calls facilitate communication among adults and alert nestlings to potential danger. While heterospecific call recognition has been extensively studied in adult birds, nestlings—lacking direct predation experience and heterospecific alarm exposure—represent an ideal system to investigate the response to interspecific warning cues. This study explored the recognition capabilities of 5–6-day-old nestlings in Oriental Reed Warbler(Acrocephalus orientalis), a common host of the Common Cuckoo(Cuculus canorus). We exposed the nestlings to playbacks of alarm calls directed at parasites and raptors from conspecific, Vinous-throated Parrotbill(Sinosuthora webbiana, sympatric species), Isabelline Shrike(Lanius isabellinus, allopatric species) and Common Tailorbird(Orthotomus sutorius, allopatric species) adults. Results indicated that there was no significant difference in the responses of nestlings to the alarm calls of conspecific and allopatric adults directed at cuckoos and sparrowhawks. In addition, interestingly, nestlings significantly reduced their begging in response to conspecific and unfamiliar allopatric Isabelline Shrike and Common Tailorbird alarm calls but exhibited a weak response to the sympatric Vinous-throated Parrotbill. Whether older warbler nestlings with more social experience exhibit stronger responses to the alarm calls of Vinous-throated Parrotbill adults requires further investigation.