Behavior Of Birds Research Articles

Temporal Acoustic Patterns of the Oriental Turtle Dove in a Subtropical Forest in China

There is an abundance of bird species in subtropical areas, but studies on the vocal behavior of non-passerines in subtropical regions are limited. In this study, passive acoustic monitoring was used to investigate the temporal acoustic patterns of the vocal activities of the Oriental Turtle Dove (Streptopelia orientalis) in Yaoluoping National Nature Reserve (YNNR) in eastern China. The results show that the vocal production of the Oriental Turtle Dove exhibited a seasonal variation, peaking in the period April–August. Additionally, its diurnal vocal activity displayed a bimodal pattern in late spring and summer, with the first peak in the morning and a secondary peak at dusk. Among weather factors, temperature significantly affected the temporal sound pattern of the Oriental Turtle Dove, instead of humidity and precipitation. This study, which was focused on sound monitoring technology, provides knowledge for further research on bird behavior and ecology. In the future, long-term sound monitoring could be used for managing and conserving bird biodiversity.

Sex-Specific Effects of Blood Serotonin on Reproductive Effort in a Small Passerine.

AbstractLaboratory animal models have shown that blood serotonin levels reflect consistent individual differences in behavioral decision-making and maternal behavior. Serotonin could also help to understand intraspecific variation in reproductive strategies, although the mechanisms are poorly understood. In this study, the relationships of plasma serotonin with breeding parameters and parental behavior were examined in wild great tits (Parus major). Females who laid eggs earlier had higher levels of serotonin in the second half of the nestling period, while no significant relationship of serotonin with clutch size, brood size, and body size was detected. In males, serotonin levels were negatively related to clutch size and brood size and positively related to body size. The association of serotonin with provisioning behavior was sex specific, and acute fear stress induced by a predator presentation did not change this relationship. Food provisioning was positively related to size-corrected serotonin levels in females and negatively related to size-corrected serotonin levels in males. These results suggest that peripheral serotonin is a sensitive marker of parental behavior and reproductive effort in wild birds, while the mechanisms linking this neurotransmitter to reproduction are probably mediated by interplay between the serotonergic system, sex hormones, and other neurotransmitters.

Are birds more afraid in urban parks or cemeteries? A Latin American study contrasts with results from Europe

The escape behaviour, measured as flight initiation distance (FID; the distance at which individuals take flight when approached by a potential predator, usually a human in the study systems), is a measure widely used to study fearfulness and risk-taking in animals. Previous studies have shown significant differences in the escape behaviour of birds inhabiting cemeteries and urban parks in European cities, where birds seem to be shyer in the latter. We collected a regional dataset of the FID of birds inhabiting cemeteries and parks across Latin America in peri-urban, suburban and urban parks and cemeteries. FIDs were recorded for eighty-one bird species. Mean species-specific FIDs ranged from 1.9 to 19.7 m for species with at least two observations (fifty-seven species). Using Bayesian regression modelling and controlling for the phylogenetic relatedness of the FID among bird species and city and country, we found that, in contrast to a recent publication from Europe, birds escape earlier in cemeteries than parks in the studied Latin American cities. FIDs were also significantly shorter in urban areas than in peri-urban areas and in areas with higher human density. Our results indicate that some idiosyncratic patterns in animal fearfulness towards humans may emerge among different geographic regions, highlighting difficulties with scaling up and application of regional findings to other ecosystems and world regions. Such differences could be associated with intrinsic differences between the pool of bird species from temperate European and mostly tropical Latin American cities, characterized by different evolutionary histories, but also with differences in the historical process of urbanization.

Modeling Species-Specific Collision Risk of Birds with Wind Turbines: A Behavioral Approach

The increasing number of wind energy sites developed globally, has consequently resulted in a green-on-green predicament, due to an increase in avian mortality caused by collisions with wind turbines. The proportion of collision-related fatalities is not evenly distributed across species, indicating that some species groups are more prone to turbine collision. Such differences between species have been proposed to be affiliated with species-specific foraging and flight behavior. The aim of this study is to investigate how the flight behavioral traits; head position, active flight, track symmetry, and track tortuosity can be used to model collision risk along with other influencing factors i.e., weather variables (temperature, wind speed, and cloud coverage) and temporal variables (time of day and time of year). The study also sought to investigate the species-specificity of the four traits in relation to the phylogenetic relatedness of the study species. This was achieved through a case study at a wind farm on the Swedish island of Gotland in which the behavior of birds from 11 different genera was studied. The flight behavior of these species was assessed using data collected by the IdentiFlight system, e.g., flight trajectories and images of the birds throughout their flight track. The results confirm the species-specificity of the four flight behaviors and indicated that all four traits can be used to predict collision risk along with species as a categorical factor. The framework provided in this study along with the results of the case study can be used to identify risk-prone species based on phylogenetic relatedness and flight behavior.

Season and sugar concentration affect bird behaviour at urban sugar-water feeders

ABSTRACT Sugar-water bird feeding in residential backyards is increasingly popular, but its effects on wildlife are poorly understood. One concern is whether it results in maladaptive behaviour, such as reliance on artificial food or increased aggression due to increased density of visiting individuals. We studied sugar-water feeder-associated bird behaviour in two cities with different climates. We investigate whether season, city, or sugar concentration influenced bird foraging activity and aggressiveness. We then test whether feeder presence affected backyard bird composition. Birds were most aggressive and used sugar-water feeders most actively in winter, especially the omnivorous native tauhou (Zosterops lateralis). We also found city and seasonal differences in sugar-water feeder usage and aggression. Further, in Auckland, the city with the warmer climate, New Zealand’s largest nectarivorous species, tūī (Prosthemadera novaeseelandiae), was more likely to be aggressive at feeders with higher sugar concentrations but foraged longer at feeders with lower sugar concentrations. Neither feeder presence nor sugar concentration influenced garden bird species richness or abundance. We discuss the effects of sugar-water feeding on bird behaviour at the global and local scale and suggest future study directions.

Light-emitting greenhouses affect daily vocalization behavior in birds

To date, studies of the effects of artificial light on wildlife have mostly focused on street lighting. However, less attention has been paid to light from greenhouses, which can be sources of substantial light pollution from autumn to early spring. We investigated how daily 4–8 h of nocturnal illumination from a greenhouse influences the time of daily vocalization of forest birds in a non-urban area. Our study revealed that birds exposed to greenhouse lightning start dawn singing and calling earlier and stop dusk vocalization later, especially before the breeding season in the second half of February. The most affected species were the European Robin (entire study period) and Blackbird (early period only), but other species also revealed a significant impact on vocal activity (calls). Our study shows that even short-duration light pollution from greenhouses in a non-urban area in the breeding season can affect bird vocalization behavior.

Behavioral plasticity mediates adaptation to changes in food provisioning following the COVID-19 lockdown in black-headed gulls (Larus ridibundus)

The 2020 COVID-19 lockdown provides an opportunity to assess how the anthropause affected the behavior of birds. Black-headed gulls (Larus ridibundus) wintering at Dianchi Lake (Yunnan Province, southwestern China) prefer to forage on easily accessible human-provided food at various sites along the lake. Following the closure of the lake because of the pandemic, synthetic food was provided at a single location. We expected that the home range size and distribution of gulls would change in response to these changes in food provisioning. A total of 91 gulls were tagged with satellite transmitters in November 2018 and March 2019, and their movements were tracked during the winter months. We analyzed their home range size and spatial distribution in four periods, SCP2019, SOP2019, SCP2020, and SOP2020 (Scenic Opening/Closing Period in 2019/2020), and the difference between SOP2019 and SCP2019 was used as the control group. The eutrophication level in the wintering periods “Nov. 2018–Apr. 2019” and “Oct. 2019–Apr. 2020” was determined using the Normalized Difference Vegetation Index (NDVI), and the coverage ratio of algal blooms and NDVI were used as indicators of the amount of naturally available food. The home range sizes of gulls were reduced in SCP2020 compared with SOP2019, SCP2019, and SOP2020. The gulls were most abundant in the 600–900 m buffer zone and least abundant in the 0–300 m buffer zone in SCP2019; they were most abundant in the 0–300 m buffer zone and least abundant in the 900–2000 m buffer zone in SCP2020. These patterns were consistent with variation in the NDVI and the coverage ratio of algal blooms among buffer zones. Changes in wintering behaviors in SCP2020 relative to other periods suggested that gulls modified their behavior following anthropause-related changes in the distribution and provisioning of food. Our findings provide insights into the role of behavioral plasticity in mediating adaptation to changes in human activities in birds.

Advanced Practical Strategies to Enhance Table Egg Production.

The global demand for table eggs has increased exponentially due to the growing human population. To meet this demand, major advances in hen genetics, nutrition, and husbandry procedures are required. Developing cost-effective and practically applicable strategies to improve egg production and quality is necessary for the development of egg industry worldwide. Consumers have shown a strong desire regarding the improvement of hens' welfare and egg quality. They also become interested in functional and designer foods. Modifications in the nutritional composition of laying hen diets significantly impact egg nutritional composition and quality preservation. According to previous scientific research, enriched egg products can benefit human health. However, producers are facing a serious challenge in optimizing breeding, housing, and dietary strategies to ensure hen health and high product quality. This review discussed several practical strategies to increase egg production, quality, and hens' welfare. These practical strategies can potentially be used in layer farms for sustainable egg production. One of these strategies is the transition from conventional to enriched or cage-free production systems, thereby improving bird behavior and welfare. In addition, widely use of plant/herbal substances as dietary supplements in layers' diets positively impacts hens' physiological, productive, reproductive, and immunological performances.

Effects of Livestock Grazing on Spatio-Temporal Patterns and Behaviour of Reeves’s Pheasant Syrmaticus reevesii

Protected areas are seeing an increase in anthropogenic disturbances in the world. Previous studies have demonstrated the impact of livestock grazing and human presence on the habitat use of birds, whereas little is known about the effect of free-ranging livestock on bird behaviour. Reeves's Pheasant (Syrmaticus reevesii) is endemic to China and has been threatened by habitat loss and fragmentation, illegal logging, and human disturbance over the past 20 years. Based on camera trapping in the Liankangshan National Nature Reserve (LKS) and the Zhonghuashan Birds Provincial Nature Reserve (ZHS), we explore the effects of livestock grazing and human activities on the spatio-temporal distribution and behavioural patterns of Reeves's Pheasant. Livestock does not appear to affect habitat use by the pheasant but changes its behavioural patterns. In addition, pheasants in areas with livestock foraged mostly during the early morning, while in areas without livestock, they foraged at dusk. Therefore, the study concludes that livestock intensity in nature reserves may have reduced pheasant suitability through altered patterns of vigilance and foraging behaviour.

The genetic variation of a mitochondrial and two behaviour‐related genes in invasive African Sacred Ibis (Threskiornis aethiopicus) populations in Taiwan

The African Sacred Ibis Threskiornis aethiopicus is an invasive bird species in Taiwan and has expanded its distribution range rapidly over the past three decades. There is limited information available on the invasion process of African Sacred Ibises in Taiwan and its genetic consequences. We investigated whether genetic factors reflected the expansion of African Sacred Ibises and determined the extent to which two behaviour‐associated genes may have facilitated invasion. The dopamine receptor gene (DRD4) and the serotonin transporter gene (SERT) have both been found to be associated with novel‐seeking and bold behaviour in birds. We hypothesized that: (1) selection on temperament traits may determine the polymorphisms in these two genes and (2) the likelihood of dispersal of African Sacred Ibis populations can be explained by the intraspecific variation at these two genes. To detect the signals of population expansion and natural selection, we compared intra‐population variation and inter‐population differentiation of DRD4 and SERT with those of a mitochondrial gene (COX1) and an additional intron. We recovered contrasting patterns of nucleotide variation between the mitochondrial and nuclear genes with no single nucleotide polymorphisms detected in COX1 compared with allelic polymorphism in DRD4 and SERT. Populations showed decreasing genetic diversity at DRD4 as their distance to the initial invasive locality increased, consistent with a rapid expansion from one founder population. However, we found little evidence of selection on DRD4 or SERT, suggesting that these behaviour‐related genes are unlikely to have played a significant role in the successful invasion of the African Sacred Ibises in Taiwan. We detected high levels of genetic variation at these two behaviour‐related genes despite the effects of inbreeding in these invasive birds.

Data for: Anthropogenic noise and light pollution additively affect sleep behaviour in free-living birds in sex- and season-dependent fashions

Data for: Anthropogenic noise and light pollution additively affect sleep behaviour in free-living birds in sex- and season-dependent fashions

Anthropogenic noise and light pollution additively affect sleep behaviour in free-living birds in sex- and season-dependent fashions

Rapid anthropogenic transformation of environments exposes organisms to diverse disturbance factors, including anthropogenic noise pollution and artificial light at night (ALAN). These sensory pollutants interfere with acquisition of, and response to, environmental cues and can be perceived as stressors. Noise pollution and ALAN are often experienced simultaneously, and are thus likely to jointly affect organisms, either additively or interactively. Yet, combined effects of noise pollution and ALAN remain poorly elucidated. We studied combined effects of noise pollution and ALAN on the sleep behaviour of a free-living songbird, the great tit (Parus major). Sleep is widely conserved across animal taxa and fulfils essential functions, and research has demonstrated independent effects of both noise and ALAN on sleep. We measured noise and light levels at nest boxes and used infrared video-recording to assess sleep behaviour. Results did not support interactive effects of noise and ALAN. However, noise pollution and ALAN were both independently related to variation in sleep behaviour, in sex- and season-dependent fashions. Males, but not females, woke up and left the nest box ∼20 min later in the noisiest as compared to quietest environments (range: 44.2–79.4 dB), perhaps because males are more sensitive to acoustical cues that are masked by noise. Furthermore, as the season progressed from November to early March, birds woke up and left the nest box ∼35 min earlier relative to sunrise on territories with the lowest, but not the highest, light levels (range: 0.01–8.5 lux). Thus, the seasonal difference in sleep duration was dampened on light polluted territories. These effects could arise if ALAN interferes with birds’ ability to sense and respond to increasing daylength, and could have fitness ramifications. Our study suggests that noise pollution and ALAN exert additive effects on sleep behaviour, and that these effects can be sex- and season-dependent.

Newcastle Disease Genotype VII Prevalence in Poultry and Wild Birds in Egypt.

Newcastle Disease Virus (NDV) genotype VII is a highly pathogenic Orthoavulavirus that has caused multiple outbreaks among poultry in Egypt since 2011. This study aimed to observe the prevalence and genetic diversity of NDV prevailing in domestic and wild birds in Egyptian governorates. A total of 37 oropharyngeal swabs from wild birds and 101 swabs from domestic bird flocks including chickens, ducks, turkeys, and pelicans, were collected from different geographic regions within 13 governorates during 2019–2020. Virus isolation and propagation via embryonated eggs revealed 91 swab samples produced allantoic fluid containing haemagglutination activity, suggestive of virus presence. The use of RT-PCR targeted to the F gene successfully detected NDV in 85 samples. The geographical prevalence of NDV was isolated in 12 governorates in domestic birds, migratory, and non-migratory wild birds. Following whole genome sequencing, we assembled six NDV genome sequences (70–99% of genome coverage), including five full F gene sequences. All NDV strains carried high virulence, with phylogenetic analysis revealing that the strains belonged to class II within genotype VII.1.1. The genetically similar yet geographically distinct virulent NDV isolates in poultry and a wild bird may allude to an external role contributing to the dissemination of NDV in poultry populations across Egypt. One such contribution may be the migratory behaviour of wild birds; however further investigation must be implemented to support the findings of this study. Additionally, continued genomic surveillance in both wild birds and poultry would be necessary for monitoring NDV dissemination and genetic diversification across Egypt, with the aim of controlling the disease and protecting poultry production.

Does the sound environment influence the behaviour of zoo-housed birds? A preliminary investigation of ten species across two zoos

In the zoo, the sound environment experienced by captive wild animals will contain numerous anthropogenic features that may elicit different responses to those stimulated by naturally created, or more biologically relevant, sounds. Husbandry activities, visitor presence and neighbouring species (free-living and captive) will all influence the sounds around zoo-housed species; an animal’s behavioural responses may therefore provide an insight into how its welfare state is influenced by this changing sound environment. This project aimed to investigate how animal behaviour was influenced by the sound environment at two large UK zoos; one situated in a more rural location and the other in an urban location. Species were selected based on their location in the zoo, the relevance of sound to their natural ecology (e.g., as a form of communication and/or for anti-predator responses) and their novelty as research subjects in the scientific literature. Behavioural data collection was conducted for five days per enclosure per zoo at the population and individual level for birds housed in different styles of enclosure. Instantaneous sampling at one-minute intervals was used to collect information on state behaviours, assessed using a pre-determined species-specific ethogram. Event behaviours were collected continuously for each observation period. The sound environment around or in the enclosure was recorded continuously during each behavioural recording session using a recorder mounted on a tripod. Results showed a variety of responses to the presence of visitors and potential associated changes to sound around the enclosure with some behaviours being more influenced by the presence of visitors (and increases in the volume of sound) compared to others, e.g., vigilance and vocalisations. Overall, birds showed few of the changes thought to indicate poor or impoverished welfare states linked to changes to the sound environment in their enclosure or to the presence of visitors, but we recommend that zoos consider further measurement and recording of sound on a species-by-species basis to capture individual responses and behavioural changes to variation in visitor number and the sound environment.

Collective action in birds

Observing the behaviour of others is a cheap and effective way of acquiring up-to-date information about the environment. Further, an animal that changes its behaviour in response to acquiring social information effectively propagates that information forwards. Although the rules that govern how individual birds detect and respond to social cues are often very simple, they are able to produce a diverse range of collective actions from which individuals can reap benefits that include predator avoidance and more accurate estimations of the environment. Understanding how and why individual-level rules that favour the emergence of collective behaviour have evolved therefore requires knowledge of the ecological and social contexts in which they are expressed. The breadth of research on social behaviours in birds is an unparalleled window into the ecology of collective behaviour and provides many opportunities to test whether different species overcome different ecological challenges using similar social rules and whether the collective behaviours of birds can act as sensors for the environment.

Avian vision

The primary reliance of birds on vision is readily and frequently asserted. Casual observations of birds completing their everyday behaviours is sufficient to convince most observers that birds are using vision to control their key behaviours. This assertion is supported by evidence that in most bird species relatively large portions of their brains are devoted to the analysis of information from vision. Also, the so-called intelligent behaviours of birds seem to be based primarily upon visual information. Thus, gaining information from vision, and using it to guide sophisticated behaviours, is seen as a vital component of what makes birds so fascinating.

Inter and intra-population variability of the migratory behaviour of a short-distance partial migrant, the Eurasian Stone-curlew Burhinus oedicnemus (Charadriiformes, Burhinidae)

Migratory behaviour in birds shows a remarkable variability at species, population and individual levels. Short-distance migrants often adopt a partial migratory strategy and tend to have a flexible migration schedule that allows a more effective response to extreme environmental variations. Weather seasonality and environmental heterogeneity have been reported as significant factors in the diversification of migratory behaviour for Mediterranean migrants, but relatively few studies investigated the migration patterns of non-passerine birds migrating within the Mediterranean basin. In this study, we investigated the migratory strategy of 40 Eurasian Stone-curlews Burhinus oedicnemus tagged with geolocators and GPS-GSM tags and belonging to continental and Mediterranean populations of the Italian peninsula. The proportion of migrants was higher in continental populations, but we observed a significant variability also within Mediterranean populations. All birds spent the winter within the Mediterranean basin. Continental Stone-curlews departed earlier in spring and later in autumn and covered longer distances than those from Mediterranean areas. The speed of migration did not change between seasons for continental birds, while Mediterranean individuals migrated faster in spring. The likelihood of departure for autumn migration of GPS-tagged birds increased when temperatures were near or below 0 °C suggesting that Stone-curlews tend to delay departure until weather conditions worsen abruptly. As a consequence of global warming in the Mediterranean, the frequency of migratory birds in the considered populations might decrease in the near future. This could affect the distribution of species throughout the year and should be taken into account when targeting conservation measures.

Foraging behaviour of an omnivorous bird varies in mixed-species groups

In mixed-species groups (MSGs), individuals from different species may locate and communicate about the presence of predators and prey quickly and accurately but may compete for food and favourable positions in the flock. Thus, foraging behaviour is likely to change when individuals participate in MSGs compared with single-species groups (SSGs). In a highly seasonal tropical environment, the foraging behaviour of omnivorous birds may also vary with fluctuations in food availability, weather, and breeding conditions. Here, we observed the foraging behaviour (food item consumed and foraging substrate) of an insectivorous-granivorous songbird, the Coal-crested finch (Charitospiza eucosma), in a savanna in central Brazil, while simultaneously sampling the grass seed production. Birds were more likely to consume grass seeds and forage on lower vertical strata (i.e., ground or herbaceous layers) in MSGs than in other social contexts (SSGs, pair or alone), suggesting they are facing interference competition from other species in MSGs or obtaining antipredator benefits in MSGs that enable them to explore preferred food resources in microhabitats more exposed to predators. As expected, Coal-crested finches were more likely to feed on grass seeds and forage on lower vertical strata when grass seed production is abundant, suggesting that they switch their diet according to the availability of their main food items: grass seeds and invertebrates. Weather and breeding seasonalities had small effects on foraging behaviour. Our results show that MSGs may have a major role in the foraging behaviour of omnivorous birds even considering the seasonal mismatching of their main food items.

Environmental and Social Influences on the Behaviour of Free-Living Mandarin Ducks in Richmond Park.

Simple SummaryCollecting information on how wild animals behave in the free-living environment can be useful for improving how such species are managed when under human care (e.g., in the zoo). Mandarin Ducks are an example of a species with a large captive population where research into the behaviour of wild birds can help with explaining and evaluating how this species is coping in captivity. This research collected data on free-living Mandarins in a large public park and compared such data to published research on captive Mandarins to evaluate any differences in time budgets. The overall aim of this research was to provide information on what behaviours are commonest amongst free-living Mandarin Ducks to help others with the assessment of behavioural normality of captive birds.Many species of birds are housed in zoos globally and are some of the most popular of animals kept under human care. Careful observations of how species live and behave in their natural habitats can provide us with important knowledge about their needs, adaptations, and internal states, allowing identification of those behaviours that are most important to the individual’s physical health and wellbeing. For this study, Mandarin Ducks (Aix galericulata) were chosen as a study species because, like many species of waterfowl, they are widely kept in both private institutions and zoos, yet little research has been conducted on their core needs in captivity. A free-living population of naturalised Mandarin Ducks living in Richmond Park was used for this research. Data on state behaviours (resting, swimming, foraging, perching, preening, and vigilance) were collected five days a week (08:00–18:00) from the 26 March to 26 May 2021. Secondly, temporal, seasonal, environmental, and animal-centric factors (e.g., Sex) were recorded to assess any impact on the Mandarin’s time-activity budget. Lastly, a comparison between free-living anmd captive activity was conducted (via the literature) to evaluate whether captive behaviours differ to how they are expressed in the wild. Results showed that free-living Mandarins predominantly rested (19.88% ± 28.97), swam (19.57% ± 19.43) and foraged (19.47% ± 25.82), with variations in activity related to factors such as vegetation cover and pond size. Results also showed differences between the time-budgets of free-living and captive Mandarins, suggesting that captive birds may not always have the opportunity to express species-typical behaviours. This research indicated that study of natural behaviours performed in the wild may help to evaluate “normal” behaviour patterns of zoo-housed individuals and provide evidence for environmental and husbandry alterations that can promote good welfare. However, any potential impact on the activity patterns of free-living species due to human interactions should be considered when assessing deviations between the behaviour of wild and captive individuals.

The role of parvalbumin neurons in the evolution of skilled behaviours.

Understanding how animals display diverse and complex behaviours remains a central question in biology. A new study in PLOS Biology suggests that the emergence of clusters of parvalbumin neurons in the forebrain could reflect a convergent mechanism underlying the evolution of skilled behaviours in birds.