Behavior Of Birds Research Articles

Passive acoustic data yields insights into bird vocalization behavior associated with invasive shrub removal

AbstractMonitoring biodiversity changes associated with ecological restoration is crucial in the current UN Decade on Restoration. Although several studies highlight the impacts of restoration on ecosystems, it is also important to understand how restoration alters species' behavior, including vocalization. Advances in conservation technology, such as passive acoustic monitoring, facilitate rapid and noninvasive monitoring. In this study, we quantified changes in the vocal behavior of a bird species in response to small‐scale restoration carried out by removing the invasive shrub, Lantana camara (lantana), in a Central Indian tropical dry forest. We examined associations between sites of varying lantana densities and the vocalization of one of its primary dispersers, red‐vented bulbul (RVBU). We found statistically significant differences in note‐length and bandwidth of RVBU vocalizations across sites. A random forest classification model showed that Lantana density was not an important predictor of RVBU vocalizations. Apart from the percentage of forest area and farms in our sites, total human population was the most important predictor for RVBU vocalizations suggesting RVBU's use of human habitations as possible resource hubs. Our findings suggest that lantana removal is not associated with significant changes in RVBU vocalization. This study provides empirical evidence that ecological restoration may not alter species' vocalization in the short term and highlights the importance of moving beyond species presence and understanding the impact of restoration on species behavior.

Influence of age on spatial and temporal migratory patterns of Black Storks from Germany

How the migration behavior of long-lived birds develops throughout their life is still a research question in ornithology that is largely unanswered. Here, we analyzed GPS data of 70 juvenile Black Storks during the first 3 years of their migration to determine the influence of age and experience on migration patterns. We focused on the choice of the migration flyway, as well as the movements in the wintering area, and the changes in departure times with increasing age. Migratory routes of German Black Storks were divided into the western (82% of all tracked individuals) and eastern flyways (16%). The central migratory flyway through Italy or Greece was taken only by two individuals and never repeatedly. In addition, we found that the wintering area decreased by almost 60% during their first 3 years of life. In addition, spring departure dates from the wintering areas also became earlier with increasing age. However, we did not find changes in departures from the breeding area in autumn. Thus, our study shows that age and migration experiences have a considerable influence on essential migratory decisions in Black Storks. Further, it also demonstrates that older storks rely strongly on previous experiences to perform their migrations efficiently.

Research note: Expert opinions of feather sucking and licking behavior in meat chicken breeder birds

Feather sucking, or feather licking, has been reported anecdotally by employees in the Australian meat chicken breeder industry, but scarcely in the scientific literature. Consequently, the causes and implications of this behavior in meat chicken breeding chickens is relatively unknown. We surveyed 17 industry experts to generate hypotheses about feather sucking behavior. We aimed to understand the frequency and when it occurs, and attempted to understand what may cause an ‘outbreak’. The recruitment of participants was intentionally biased towards Australian perspectives; only 5 of the 17 participants were international. All participants, except 1, had seen feather sucking/licking behavior (94.1%) and most participants (80%) suggested that the behavior was most frequently observed during rearing. Participants presented varying concerns about this behavior, ranging from the perspective that it was ‘normal’ and had no impact on welfare, to concerns about mating injuries due to damaged feathers, increased risk of feather pecking and cannibalism, and psychological stress indicated by expression of repetitive (seemingly) functionless behavior. ‘Feather licking’, ‘feather sucking’, ‘feather eating’, and ‘feather pecking’ were terms used interchangeably, leading to confusion by participants about the cause and implications of the target behavior. The most common factors reported as the cause were boredom (52.9%), nutritional deficiencies (47.1%), and feed restriction (41.2%) and more than 80% of respondents agreed that stress contributes to feather sucking. The outputs from this study reflect only a small, but expert, number of opinions on feather sucking/licking behaviors in the Australian meat chicken breeder industry. A systematic understanding of this behavior is needed to provide insight into causation and the implications for welfare.

BirdCollect: A Comprehensive Benchmark for Analyzing Dense Bird Flock Attributes

Automatic recognition of bird behavior from long-term, un controlled outdoor imagery can contribute to conservation efforts by enabling large-scale monitoring of bird populations. Current techniques in AI-based wildlife monitoring have focused on short-term tracking and monitoring birds individually rather than in species-rich flocks. We present Bird-Collect, a comprehensive benchmark dataset for monitoring dense bird flock attributes. It includes a unique collection of more than 6,000 high-resolution images of Demoiselle Cranes (Anthropoides virgo) feeding and nesting in the vicinity of Khichan region of Rajasthan. Particularly, each image contains an average of 190 individual birds, illustrating the complex dynamics of densely populated bird flocks on a scale that has not previously been studied. In addition, a total of 433 distinct pictures captured at Keoladeo National Park, Bharatpur provide a comprehensive representation of 34 distinct bird species belonging to various taxonomic groups. These images offer details into the diversity and the behaviour of birds in vital natural ecosystem along the migratory flyways. Additionally, we provide a set of 2,500 point-annotated samples which serve as ground truth for benchmarking various computer vision tasks like crowd counting, density estimation, segmentation, and species classification. The benchmark performance for these tasks highlight the need for tailored approaches for specific wildlife applications, which include varied conditions including views, illumination, and resolutions. With around 46.2 GBs in size encompassing data collected from two distinct nesting ground sets, it is the largest birds dataset containing detailed annotations, showcasing a substantial leap in bird research possibilities. We intend to publicly release the dataset to the research community. The database is available at: https://iab-rubric.org/resources/wildlife-dataset/birdcollect

Urban noise slows down the antipredator reaction of Eurasian Magpies

Urban areas are known to have high levels of noise pollution, which can impact an animal’s antipredator behavior. Noise can either distract the animal or mask the sounds of a predator, increasing the animal’s vulnerability to predation. However, the prey may increase vigilance in noisier environments, thus reducing energy and time spent on other activities. Alert Distance (AD) refers to the distance at which an animal becomes alert to a potential predator approaching. Flight Initiation Distance (FID) is the distance from the potential predator at which the animal flees. We studied the impact of ambient noise pollution on the AD and a corrected FID (FID/AD) of Eurasian Magpies (Pica pica) using a field investigator as a potential predator walking towards birds at a constant speed. We found that the noise level did not affect the AD. Still, noise had a negative effect on the Eurasian Magpies’ FID/ADs, suggesting that noise may slow their reaction to a potential threat but not their ability to detect it. Thus, our research highlights that urban noise pollution can increase an individual's vulnerability to predation, even when predators are still detectable. Ambient noise may distract the bird by diverting some of its limited attention and causing a delayed response to the predators. Alternatively, noise could be masking auditory cues that would have otherwise been added together with visual cues to cause an enhanced response. More research is necessary to understand the effects of noise pollution on the antipredator behavior of birds in urban areas, taking into account the specific strategies and adaptations of each species.

Effects of foraging mode and group pattern on vigilance behavior in water birds: a case study of mallard and black-winged stilt

Vigilance behavior is affected by many factors including foraging mode and group pattern which we attempted to understand through a case study of mallard Anas platyrhynchos and black-winged stilt Himantopus himantopus in the Hengshui Lake National Nature Reserve, China. Mallard, a swimming bird, forages in irregular and loose circular groups in open water and its foraging mode (with its head underwater looking for food) does not allow for simultaneous monitoring of potential threats above the water surface, which is why its foraging is called “blind period of foraging”. In contrast, black-winged stilt is a wading bird and forages along riversides in long linear foraging groups. Its long beak, neck and legs enable it to scan around while foraging without any obviously blind period. We used the focal sampling method and measured vigilance behavior by the time spent vigilant, vigilance frequency, average duration of vigilance, alert distance and flee distance for the two species. We predicted higher levels of vigilance and longer alert and flee distance in mallard with long blind periods of foraging. Our results indicated significant differences (p

Touristic activity and disturbances over Nearctic migratory birds oin the coast of Piauí State, Brazil

The migration of birds is a phenomenon that leads thousands of individuals to move between different areas for feeding and breeding, with these movements often crossing geopolitical borders. This behavior is crucial for the survival of many species. However, anthropogenic impacts are affecting the habitats of these species, contributing to the decline in bird populations. In light of this, the aim of this study was to analyze the disturbances caused by tourist activities on migratory birds visiting the estuaries of the Cardoso and Camurupim rivers on the coast of the state of Piauí and propose measures to mitigate disturbances on the birds. Samples were taken at three observation points, where changes in bird behavior in response to tourist activities were analyzed. Binoculars, a photographic camera, and a laser rangefinder were used to assist in delineating impact zones. Although various tourist activities occur in the region, the main disturbances are caused by kitesurfing and tourists walking near the feeding or resting areas of the species. Calidris minutilla, Calidris pusilla, Calidris alba, Actitis macularius, and Charadriius semipalmatus were the least sensitive species to disturbances, reacting more frequently within impact zones Z = 0-30m and Z = 30-60m, while the species Pluvialis squatarola, Numenius hudsonicus, Tringa melanoleuca, Calidris canutus, Limnodromus griseus, and Pandion haliaetus showed greater escape distances. The results of this study show that tourists walking and kitesurfing are the main activities impacting migratory birds in the region, highlighting the need for measures to mitigate such impacts. Based on the results, the creation of minimum protection zones of 160m and 200m is recommended to mitigate disturbances caused by the approach of bathers and kitesurfers.

Alert and flight initiation distances of Chilean Flamingo and American Oystercatcher to anthropogenic stimuli in a stopover site

ABSTRACT Tourism provides benefits, such as economic incentives, increasing support for conservation. However, it can also evoke responses in wildlife and be analogous to predation risk. As tourism increases, adequate planning and management is necessary. Chilean Flamingos (Phoenicopterus chilensis) and American Oystercatchers (Haematopus palliatus) were exposed to four stimuli (single walker, group of walkers, car, and kayak) in a stopover site to determine their response and estimate minimal approach distances, controlling the effect of potentially influential factors. Flight initiation distance and the distance at which birds change its posture or orientation to monitor an approaching threat (alert distance) were identified as response distances. Kayaks and cars allowed closer approaches than single walkers and groups of walkers for both species. The Chilean Flamingo exhibited responses to approaching stimuli at longer distances compared with oystercatchers. Potential factors (starting distance, month, season, initial behavior, and wind speed) including large variations among individuals, and influenced bird responses. To reduce the effects of tourists on bird behavior in an important stopover site, the minimal approach distance can be set at 80 m for the American Oystercatcher on the beach and 240 m for the Chilean Flamingo when walking and 207 m when kayaking in the estuary.

Do domestic budgerigars perceive predation risk?

Predation risk may affect the foraging behavior of birds. However, there has been little research on the ability of domestic birds to perceive predation risk and thus adjust their feeding behavior. In this study, we tested whether domestic budgerigars (Melopsittacus undulatus) perceived predation risk after the presentation of specimens and sounds of sparrowhawks (Accipiter nisus), domestic cats (Felis catus), and humans, and whether this in turn influenced their feeding behavior. When exposed to visual or acoustic stimuli, budgerigars showed significantly longer latency to feed under sparrowhawk, domestic cat, and human treatments than with controls. Budgerigars responded more strongly to acoustic stimuli than visual stimuli, and they showed the longest latency to feed and the least number of feeding times in response to sparrowhawk calls. Moreover, budgerigars showed shorter latency to feed and greater numbers of feeding times in response to human voices than to sparrowhawk or domestic cat calls. Our results suggest that domestic budgerigars may identify predation risk through visual or acoustic signals and adjust their feeding behavior accordingly.

Dangerous neighbours: Birds and bird-eating bats sharing tree cavities.

Mounting evidence indicates the non-consumptive effects of predators significantly impact prey physiology, ecology and behaviour. Passerine birds experience adverse effects on nesting and reproductive success when in proximity to predators. Fear of predators is context-dependent and influenced by hunting habitats and foraging strategies. While some bat species prey on birds, the greater noctule (Nyctalus lasiopterus) stands out by specialising in avian prey, especially during peak bird migration. N. lasiopterus is thought to seize avian prey in flight, but direct evidence is lacking. If birds were taken from nests, they would likely avoid nesting near these bats. However, no observations support this view. This study documents the successful reproduction of Eurasian blue tits (Cyanistes caeruleus) nesting alongside a colony of approximately 25 greater noctules. This bird species is a prey species for greater noctules in Italy. Over about 1 month (April-May 2023), we observed parent birds provisioning food to chicks, with at least two chicks alive and fed outside the tree cavity by the end of the period. While acknowledging the limitations of a single observation, we propose that this previously unknown behaviour indirectly supports the idea that greater noctules only capture avian prey in flight, not within confined spaces. This observation challenges the perception that these bats pose a threat when sharing roosting spaces in trees, as evidenced in our observed case. We hope this novel observation inspires future research on variations in bird nesting behaviour and reproductive success in the presence of bird-eating bats, as well as an assessment of the long-term impact on population dynamics and reproductive success of nesting birds sharing such roosting spaces.

Aggregated time‐series features boost species‐specific differentiation of true and false positives in passive acoustic monitoring of bird assemblages

AbstractPassive acoustic monitoring (PAM) has gained increasing popularity to study behaviour, habitat preferences, distribution and community assembly of birds and other animals. Automated species classification algorithms like ‘BirdNET’ are capable of detecting and classifying avian vocalizations within extensive audio data, covering entire species assemblages. PAM reveals substantial potential for biodiversity monitoring that informs evidence‐based conservation. Nevertheless, fully realizing this potential remains challenging, especially due to the issue of false‐positive species detections. Here, we introduce an optimized thresholding framework, which incorporates contextual information extracted from the time‐series of automated species detections (i.e. covariates on quality and quantity of species' detections measured at varying time intervals) to improve the differentiation of true and false positives. We verified a sample of BirdNET detections per species and modelled species‐specific thresholds using conditional inference trees. These thresholds were designed to minimize false‐positive detections while maximizing the preservation of true positives in the dataset. We tested this framework for a large dataset of BirdNET detections (5760 h of audio data, 60 sites) recorded over an entire breeding season. Our results revealed considerable interspecific variability of precision (percentage of true positives) within raw BirdNET data. Our optimized thresholding approach achieved high precision (≥0.9) for 70% of the 61 detected species, while species‐specific thresholds solely relying on the BirdNET confidence scores achieved high precision for only 31% of the species. Conservative universal thresholds (not species‐specific) reached high precision for 48% of the species. Our thresholding approach outperformed previous thresholding approaches and enhanced interspecific comparability for bird community analyses. By incorporating contextual information from the time‐series of species detections, the differentiation of true and false positives was substantially improved. Our approach may enhance a straightforward application of PAM in biodiversity research, landscape planning and evidence‐based conservation.

ANALYSIS OF THE DEGREE OF STUDY AND GLOBAL EXPERIENCE IN OPTIMIZING URBAN NOISE POLLUTION

А collection and analysis of domestic and international publications on the impact of noise pollution on the physical and emotional well-being of mega-city residents were conducted. It was found that noise pollution directly affects the quality of life and the physical and mental health of people, leading to significant economic losses through medical expenses, deaths, and a decrease in the market value of real estate located near noise sources. Moreover, it was discovered that noise negatively influences not only the physical well-being of humans but also the behavior of urban animals and birds, compelling them to adapt their mating rituals and communication methods. While these behavioral changes help animals be more audible in noisy environments, they impact the reproductive success of certain species, potentially leading to their extinction and causing an ecological catastrophe. The study identified a global trend of lagging efforts to combat urban noise and solve problems only after their existence is acknowledged. The research explored the primary internationally recognized and widely used tools for reducing noise levels in urban environments, including methods within the field of landscape architecture: functional zoning of urban areas, construction of noise reduction screens (NRS), installation of noise-absorbing road surfaces, traffic restrictions, or speed limits, and the creation of green barriers, among others. Furthermore, the article outlined the main trends in the future development of improving sound comfort in cities, such as the establishment of "quiet zones" and the creation of unique soundscapes in contemporary mega-cities. Examples include the iconic sounds of Big Ben in London or the call to prayer from the Masjid al-Haram in Mecca, which provide emotionally rich experiences. In a broader sense, acoustic comfort should not be considered solely as the absence of noise but rather as a situation where acoustic environments offer significant opportunities for human development and careful consideration of their physical and mental well-being.

Gonadotropin-inhibitory hormone and its receptors in teleosts: Physiological roles and mechanisms of actions

Gonadotropin-inhibitory hormone (GnIH) was the first reported hypothalamic neuropeptide inhibiting reproduction in vertebrates. Since its discovery in the quail brain, its orthologs have been identified in a variety of vertebrate species and even protochordates. Depending on the species, the GnIH precursor polypeptides comprise two, three or four mature peptides of the RFamide family. It has been well documented that GnIH inhibits reproduction at the brain-pituitary–gonadal levels and participates in metabolism, stress response, and social behaviors in birds and mammals. However, most studies in fish have mainly been focused on the physiological roles of GnIH in the control of reproduction and results obtained are in some cases conflicting, leaving aside its potential roles in the regulation of other functions. In this manuscript we summarize the information available in fish with respect to the structural diversity of GnIH peptides and functional roles of GnIH in reproduction and other physiological processes. We also highlight the molecular mechanisms of GnIH actions on target cells and possible interactions with other neuroendocrine factors.

The dynamic landscape of chromatin accessibility and active regulatory elements in the mediobasal hypothalamus influences the seasonal activation of the reproductive axis in the male quail under long light exposure

BackgroundIn cold and temperate zones, seasonal reproduction plays a crucial role in the survival and reproductive success of species. The photoperiod influences reproductive processes in seasonal breeders through the hypothalamic-pituitary-gonadal (HPG) axis, in which the mediobasal hypothalamus (MBH) serves as the central region responsible for transmitting light information to the endocrine system. However, the cis-regulatory elements and the transcriptional activation mechanisms related to seasonal activation of the reproductive axis in MBH remain largely unclear. In this study, an artificial photoperiod program was used to induce the HPG axis activation in male quails, and we compared changes in chromatin accessibility changes during the seasonal activation of the HPG axis.ResultsAlterations in chromatin accessibility occurred in the mediobasal hypothalamus (MBH) and stabilized at LD7 during the activation of the HPG axis. Most open chromatin regions (OCRs) are enriched mainly in introns and distal intergenic regions. The differentially accessible regions (DARs) showed enrichment of binding motifs of the RFX, NKX, and MEF family of transcription factors that gained-loss accessibility under long-day conditions, while the binding motifs of the nuclear receptor (NR) superfamily and BZIP family gained-open accessibility. Retinoic acid signaling and GTPase-mediated signal transduction are involved in adaptation to long days and maintenance of the HPG axis activation. According to our footprint analysis, three clock-output genes (TEF, DBP, and HLF) and the THRA were the first responders to long days in LD3. THRB, NR3C2, AR, and NR3C1 are the key players associated with the initiation and maintenance of the activation of the HPG axis, which appeared at LD7 and tended to be stable under long-day conditions. By integrating chromatin and the transcriptome, three genes (DIO2, SLC16A2, and PDE6H) involved in thyroid hormone signaling showed differential chromatin accessibility and expression levels during the seasonal activation of the HPG axis. TRPA1, a target of THRB identified by DAP-seq, was sensitive to photoactivation and exhibited differential expression levels between short- and long-day conditions.ConclusionOur data suggest that trans effects were the main factors affecting gene expression during the seasonal activation of the HPG axis. This study could lead to further research on the seasonal reproductive behavior of birds, particularly the role of MBH in controlling seasonal reproductive behavior.

Spontaneous tempo production in cockatiels (Nymphicus hollandicus) and jungle crows (Corvus macrorhynchos)

Musical and rhythmical abilities are poorly documented in non-human animals. Most of the existing studies focused on synchronisation performances to external rhythms. In humans, studies demonstrated that rhythmical processing (e. g. rhythm discrimination or synchronisation to external rhythm) is dependent of an individual measure: the individual tempo. It is assessed by asking participants to produce an endogenous isochronous rhythm (known as spontaneous motor tempo) without any specific instructions nor temporal cue. In non-human animal literature, studies describing spontaneous and endogenous production of motor tempo without any temporal clue are rare. This exploratory study aims to describe and compare the spontaneous motor tempo of cockatiels and jungle crows. Data were collected on spontaneous beak drumming behaviours of birds housed in laboratory. Inter beak strokes intervals were calculated from sound tracks of videos. The analyses revealed that inter beak strokes intervals are non-randomly distributed intervals and are isochronous. Recorded spontaneous motor tempos are significantly different among some cockatiels. Since we could only conduct statistical analysis with one corvid, we cannot conclude about this species. Our results suggest that cockatiels and jungle crows have individual tempos, thus encouraging further investigations.

Diversity and evolution of the vertebrate chemoreceptor gene repertoire

Chemoreception – the ability to smell and taste – is an essential sensory modality of most animals. The number and type of chemical stimuli that animals can perceive depends primarily on the diversity of chemoreceptors they possess and express. In vertebrates, six families of G protein-coupled receptors form the core of their chemosensory system, the olfactory/pheromone receptor gene families OR, TAAR, V1R and V2R, and the taste receptors T1R and T2R. Here, we study the vertebrate chemoreceptor gene repertoire and its evolutionary history. Through the examination of 1,527 vertebrate genomes, we uncover substantial differences in the number and composition of chemoreceptors across vertebrates. We show that the chemoreceptor gene families are co-evolving, highly dynamic, and characterized by lineage-specific expansions (for example, OR in tetrapods; TAAR, T1R in teleosts; V1R in mammals; V2R, T2R in amphibians) and losses. Overall, amphibians, followed by mammals, are the vertebrate clades with the largest chemoreceptor repertoires. While marine tetrapods feature a convergent reduction of chemoreceptor numbers, the number of OR genes correlates with habitat in mammals and birds and with migratory behavior in birds, and the taste receptor repertoire correlates with diet in mammals and with aquatic environment in fish.

Effect of immunization against OPN5 on the reproductive performance in Shan Partridge ducks under different photoperiods

Photoperiod is an important environmental factor that influences seasonal reproduction behavior in birds. Birds translate photoperiodic information into neuroendocrine signals through deep brain photoreceptors (DBPs). OPN5 has been considered candidate DBPs involved in regulating seasonal reproduction in birds. We found that OPN5 could mediate light to regulate the follicle development in ducks. In this study, we further verified the effect of OPN5 on follicular development in Shan Partridge ducks by immunizing against the extracellular domain (ECD) of OPN5. We investigated the specific regulatory mechanism of photoperiod mediated by OPN5 on the reproductive activity of ducks. The trial randomly divided 120 Shan Partridge ducks into 3 groups with different treatments: the immunization of OPN5 group was done at d0, d15, d30, and d40 with 1 mL of vaccine containing OPN5 protein (thus containing 1, 1, 0.5, and 0.5 mg of OPN5-KLH protein), and the control group (CS and CL groups) was injected at the same time with the same dose of OPN5-uncontained blank vaccine. The group of CS (900 lux), OPN5 (600 lux), and CL (600 lux) lasted for 40 d in 12 L:12 D photoperiods, respectively. Then, the groups of CS, OPN5, and CL subsequently received 12 L:12 D, 12 L:12 D, and 17 L:7 D light treatments for 33 d, respectively. The ducks were caged in 3 constant rooms with the same feeding conditions for each group, free water, and limited feeding (150 g per duck each day). Duck serum and tissue samples were collected at d 40, d 62, and d 73 (n = 12). It was found that before prolonged light, the group of immunization (group OPN5) and the group of strong light intensity (group CS) were higher than the group of CL in egg production. Subsequent to prolonged light, the group CL in egg production rose about the same as the group immunization, while the strong light group (group CS) was lower. Group OPN5 increased the ovarian index of ducks, and both the immunization of group OPN5 and group CL (extended light) increased the thickness of the granular layer and promoted the secretion of E2, P4, LH, and PRL hormones. Compared with group CS, group CL and OPN5 increased the mRNA level and protein expression of OPN5 in the hypothalamus on d 62 and d 73 (P < 0.05). The gene or protein expression patterns of GnRH, TRH, TSHβ, DIO2, THRβ, VIP, and PRL were positively correlated with OPN5, whereas the gene expression patterns of GnIH and DIO3 were negatively correlated with OPN5. The results showed that immunization against OPN5 could activate the corresponding transmembrane receptors to promote the expression of OPN5, up-regulate the expression of TSHβ and DIO2, and then regulate the HPG axis-related genes to facilitate the follicular development of Shan Partridge ducks. In addition, in this experiment, prolonging the photoperiod or enhancing the light intensity could also enhance follicle development, but the effect was not as significant as immunizing against OPN5. Our results will offer beneficial data and more supportive shreds of evidence in favor of elucidating the role of OPN5 in relation to photoperiods and reproduction.

Synchrony of Bird Migration with Global Dispersal of Avian Influenza Reveals Exposed Bird Orders

Highly pathogenic avian influenza virus (HPAIV) A H5, particularly clade 2.3.4.4, has caused worldwide outbreaks in domestic poultry, occasional spillover to humans, and increasing deaths of diverse species of wild birds since 2014. Wild bird migration is currently acknowledged as an important ecological process contributing to the global dispersal of HPAIV H5. However, this mechanism has not been quantified using bird movement data from different species, and the timing and location of exposure of different species is unclear. We sought to explore these questions through phylodynamic analyses based on empirical data of bird movement tracking and virus genome sequences of clade 2.3.4.4 and 2.3.2.1. First, we demonstrate that seasonal bird migration can explain salient features of the global dispersal of clade 2.3.4.4. Second, we detect synchrony between the seasonality of bird annual cycle phases and virus lineage movements. We reveal the differing exposed bird orders at geographical origins and destinations of HPAIV H5 clade 2.3.4.4 lineage movements, including relatively under-discussed orders. Our study provides a phylodynamic framework that links the bird movement ecology and genomic epidemiology of avian influenza; it highlights the importance of integrating bird behavior and life history in avian influenza studies.

High-Frequency Local Field Potential Oscillations for Pigeons in Effective Turning

Flexible turning behavior endows Homing Pigeons (Columba livia domestica) with high adaptability and intelligence in long-distance flight, foraging, hazard avoidance, and social interactions. The present study recorded the activity pattern of their local field potential (LFP) oscillations and explored the relationship between different bands of oscillations and turning behaviors in the formatio reticularis medialis mesencephali (FRM). The results showed that the C (13–60 Hz) and D (61–130 Hz) bands derived from FRM nuclei oscillated significantly in active turning, while the D and E (131–200 Hz) bands oscillated significantly in passive turning. Additionally, compared with lower-frequency stimulation (40 Hz and 60 Hz), 80 Hz stimulation can effectively activate the turning function of FRM nuclei. Electrical stimulation elicited stronger oscillations of neural activity, which strengthened the pigeons’ turning locomotion willingness, showing an enhanced neural activation effect. These findings suggest that different band oscillations play different roles in the turning behavior; in particular, higher-frequency oscillations (D and E bands) enhance the turning behavior. These findings will help us decode the complex relationship between bird brains and behaviors and are expected to facilitate the development of neuromodulation techniques for animal robotics.

Extra‐pair paternity enhances the reproductive fitness of urban Chinese blackbird

Urbanization is a human‐induced process of rapid habitat change that can affect the reproductive success of animals. The occurrence of extra‐pair paternity (EPP) may be sensitive to changes in urban ecological conditions. In this study, the Chinese blackbird Turdus mandarinus, a common breeding bird in southern Chinese cities, was selected as the focus species to explore the EPP patterns of monogamous birds in developing cities and the relationship between pairs. Over four breeding seasons, 316 Chinese blackbird nestlings and 20 adults in both urban and rural areas were monitored and genotyped for 11 microsatellite loci to determine progeny affinity. We confirmed that both the brood size and hatching rate of EPP nests were significantly larger than those of within‐pair paternity (WPP) nests. The body mass, beak length, head length, and body length of 12‐day age extra‐pair offspring (EPO) were significantly greater than those of within‐pair offspring (WPO), suggesting important benefits of EPP. However, in accordance with the analyses of nest ecological variables, we concluded that EPP occurs most often in areas with low urbanization levels, indicating some constraints for this reproductive strategy in cities. Our findings provide new insights about how this growing human‐induced landscape change affects mating behaviour in birds, an important aspect in avian ecology and evolution.