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What factors affect the ‘flocking’ of birdwatchers during bird rarity observations?
Abstract Detecting rare bird species is an essential aspect of ornithological culture. The pursuit of observing rare bird species is not only a key facet of birdwatching tourism but also a fascinating intersection between ornithology and sociology. However, patterns in birdwatcher gatherings around rare birds and the factors affecting these patterns in situ are largely unexplored. We directly asked 50 birdwatchers and analysed available photos to obtain details on birdwatcher gatherings at the occasion of 103 observations of 71 rare species recorded in 1996–2022 in Poland. Our analysis revealed that the number of people participating in rare bird observations was influenced by the rarity status of the species (rarer species attracted larger groups), the year (with an increase in recent years) and the interaction between these factors (there was an increasing trend for birdwatchers to ‘twitch’, that is participate in sightings of very rare bird species, in recent years). Furthermore, distance to urban centres significantly negatively affected the size of birdwatcher groups. In addition, we found that the proportion of observers who successfully saw a birding rarity at each site decreased in recent years but increased during the weekend. We also found that the proportion of women in these crowds has grown in recent years and that female birdwatchers were more willing to participate in observations of more common rarities than male birdwatchers. Our results indicate that birdwatching gatherings around bird rarities can be impacted by several factors, including the general rarity of species, year and distance to cities. A dynamic increase in the proportion of females participating in birdwatching in Poland resembles trends reported in other countries. Increased female engagement in observations of more common rarities may be potentially influenced by distinct motivations. Read the free Plain Language Summary for this article on the Journal blog.
Urban birds' tolerance towards humans was largely unaffected by COVID-19 shutdown-induced variation in human presence
AbstractThe coronavirus disease 2019 (COVID-19) pandemic and respective shutdowns dramatically altered human activities, potentially changing human pressures on urban-dwelling animals. Here, we use such COVID-19-induced variation in human presence to evaluate, across multiple temporal scales, how urban birds from five countries changed their tolerance towards humans, measured as escape distance. We collected 6369 escape responses for 147 species and found that human numbers in parks at a given hour, day, week or year (before and during shutdowns) had a little effect on birds’ escape distances. All effects centered around zero, except for the actual human numbers during escape trial (hourly scale) that correlated negatively, albeit weakly, with escape distance. The results were similar across countries and most species. Our results highlight the resilience of birds to changes in human numbers on multiple temporal scales, the complexities of linking animal fear responses to human behavior, and the challenge of quantifying both simultaneously in situ.
Diet analysis and the assessment of plastic and other indigestible anthropogenic litter in the white stork pellets
Sex matters: European urban birds flee approaching women sooner than approaching men
Abstract Flight initiation distance (FID) is a metric often used to study an individual's perceptions of risk when facing a predatory threat. Longer FID indicates lower risk‐taking, while shorter FID identifies bolder individuals who tolerate greater risk. Until now, no studies have tested the potential effect of the observer's sex on the escape behaviour of wild birds. Given observed differences in how laboratory animals may respond to the sex of humans interacting with them, the lack of reports in the field is surprising. In five European countries, we tested whether urban birds perceived the risk posed by approaching female versus male observers differently, using FID as a response variable. First, we matched the female and male observers according to their height and clothing. Then, we fitted Bayesian regression models, controlling for the phylogenetic relatedness of bird species, to test for the effect of human observer sex after controlling for a variety of other important factors known to explain variation in FID (starting distance, flock size, sex of the target bird, land use characteristics and vegetation cover). We found that male birds were more risk‐tolerant than females and – unexpectedly—birds in general escaped sooner when approached by women than by men. The escape difference associated with the observer's sex (~1 m longer when approached by women than by men) was consistent in populations across all five examined European countries. We discussed various hypotheses to explain birds' escape responses related to the observer's sex; however, further research is necessary to fully understand this phenomenon. Read the free Plain Language Summary for this article on the Journal blog.
Syntactically aberrant vocalization in cuckoos disrupts communication but triggers host responses
A diet perspective on the impact of the COVID-19 lockdown on urban bird assemblages
The COVID‐19 pandemic, which significantly altered human activities, particularly in urban areas, presented a unique opportunity to explore the dynamics of wildlife–human coexistence. In this study, we conducted bird counts in 36 parks in Poznań, Poland, before (2019) and during (2020) the pandemic lockdown, and assessed the impact of lockdown‐induced changes in human activity on the presence of birds with different diet type in the city. We found a notable decrease in the occurrence of granivorous and waste‐feeding birds in urban areas during the pandemic, but the presence of birds feeding mainly on other food sources remained relatively unchanged. This study provides initial evidence of a cross‐species and diet type‐related decline in bird diversity in urban parks during the COVID‐19 pandemic.
Climate change is associated with asynchrony in arrival between two sympatric cuckoos and both host arrival and prey emergence
Matching the timing of spring arrival to the breeding grounds with hosts and prey is crucial for migratory brood parasites such as cuckoos. Previous studies have focused mostly on phenological mismatch between a single cuckoo species and its hosts but information regarding climate-driven mismatch between multiple sympatric cuckoo species and their hosts and invertebrate prey is still lacking. Here, we analysed long-term data (1988–2023) on the first arrival date of two declining migratory cuckoo species and their 14 migratory host species breeding in sympatry and prey emergence date in Tatarstan (southeast Russia). We found that the common cuckoo ( Cuculus canorus ; wintering in Africa) generally arrived on breeding grounds earlier than the oriental cuckoo ( Cuculus optatus ; wintering in southeast Asia and Australia). Both cuckoos have advanced their arrival dates over 36 years but less than their hosts, potentially resulting in an increasing arrival mismatch between cuckoos and their hosts. Moreover, cuckoo arrival advanced less than the emergence date of their prey over time. These observations indicate that climate change may disrupt co-fluctuation in the phenology of important life stages between multiple sympatric brood parasites, their hosts and prey with potential cascading consequences for population dynamics of involved species.
Urban birds' detectability is affected by inter‐ and intraspecific variation in shyness
Detection probabilities differ between bird species as a function of their life history and ecological and behavioural traits, inevitably introducing bias in their abundance and occupancy estimates. However, the effects of behavioural traits such as species shyness and vigilance on detectability remain poorly understood. Here, we estimated the species‐specific level of shyness (estimated using flight initiation distance) and vigilance (alert distance) towards the human observer and their within‐species variation for 18 bird species, and accompanied those with species detectability levels estimated during point counts in urban green areas in Prague, Czechia. We found that species detectability increased with inter‐ and intraspecific variation in birds' shyness, but was not associated with the inter‐ and intraspecific variation in birds' vigilance. Our study suggests that considering variation in birds' shyness towards human observers might increase the precision of species abundance and occupancy estimates during field surveys such as point and transect counts, at least in urban habitats.
Behavioral convergence under urbanization: An overlooked dimension of biotic homogenization
A variety of human activities, especially urbanization, are not only homogenizing species composition but also eroding behavioral diversity. This Essay introduces the concept of behavioral homogenization: the human-driven convergence of behavioral traits across individuals, populations, and species across space and time. Global examples of fear responses, foraging, communication, activity patterns, social behavior, cognition and exploration, habitat use, breeding-site choice, migration, and heterospecific interaction networks are used to argue that spatial and temporal beta-diversity in behavior is shrinking in human-dominated landscapes. Ecological and evolutionary consequences, including for animal cultures and human–wildlife conflict, are outlined and opportunities to quantify and integrate behavioral homogenization into biodiversity conservation and management are highlighted.
Bird tolerance to humans in open tropical ecosystems
AbstractAnimal tolerance towards humans can be a key factor facilitating wildlife–human coexistence, yet traits predicting its direction and magnitude across tropical animals are poorly known. Using 10,249 observations for 842 bird species inhabiting open tropical ecosystems in Africa, South America, and Australia, we find that avian tolerance towards humans was lower (i.e., escape distance was longer) in rural rather than urban populations and in populations exposed to lower human disturbance (measured as human footprint index). In addition, larger species and species with larger clutches and enhanced flight ability are less tolerant to human approaches and escape distances increase when birds were approached during the wet season compared to the dry season and from longer starting distances. Identification of key factors affecting animal tolerance towards humans across large spatial and taxonomic scales may help us to better understand and predict the patterns of species distributions in the Anthropocene.
Harnessing iEcology data to uncover invasive species behaviour
Abstract Invasive animal species threaten ecosystems, biodiversity and human livelihoods. Behavioural traits such as boldness, exploratory tendencies, learning ability and social interactions are known to influence invasion success. Yet these behavioural traits remain underexplored due to challenges in observing behaviour across large spatial and temporal scales. The emerging field of iEcology—studying ecology using digital data such as online photos, videos, sounds and text, generated for other purposes—offers a novel and scalable approach for investigating invasive species behaviour. Here, we demonstrate the application of iEcology to uncover novel insights into the behaviour of invasive species, such as dominance over the native species, interactions with native species or increased tolerance to humans, all critical for assessing species' invasion potential and management. We also discuss challenges of applying iEcology to studying the behaviour of invasive animals and highlight the need for careful validation and complementary methods. Finally, we highlight ways and provide a workflow to maximise the potential of iEcology for advancing the study of invasive species behaviour. We advocate for integrating iEcology into invasion science to advance our understanding of animal behaviours accompanying invasion success and ultimately to support the monitoring, management and mitigation strategies of biological invasions. We argue that iEcology is best viewed as a complementary tool that enriches traditional behavioural ecology and invasion biology, enabling rapid, accessible insights into one of the most urgent ecological issues of our time.
White stork Ciconia ciconia nests as an attractant to birds and bats
AbstractWhite storks (Ciconia ciconia), an emblematic bird of high conservation interest, build massive nests which are also important breeding sites for other birds. However, their role as a potential source of food for foraging birds and bats is unexplored. In this study, we counted insectivorous aerially foraging birds (swallows, martins, and swifts), sparrows, and bats foraging around 51 pairs of white storks’ nest and control sites in Poland. The number of birds was significantly higher near active white stork nests than control sites, but this effect was invisible for bats. White storks provide important benefits to the conservation of co-occurring species.