Ibis最新文献

Understanding how diverse assemblages of scavengers can coexist on shared ecological resources is a fundamental challenge in community ecology. However, current approaches typically focus on behaviour at carcass provisioning sites, missing how important differences in movement behaviour and foraging strategies can facilitate sympatric species coexistence. Such information is particularly important for vultures – obligate scavengers representing the most endangered avian foraging guild. Their loss from ecosystems can trigger trophic cascades, mesopredator release and disease outbreaks. We provide the first-ever analyses of GPS location data from wild King Vultures Sarcoramphus papa and Greater Yellow-headed Vultures Cathartes melambrotus, coupled with trait data (from both wild-living and museum specimens) and visitation data from camera traps deployed at provisioned carcasses, to characterize vulture flight behaviour and strategies in the Peruvian Amazon. We found marked species differences in several key movement characteristics, including: King Vultures having home-ranges five times larger, average flight heights four times greater and ground speeds 40% faster than those of Greater Yellow-headed Vultures. Despite these differences, both species flew similar distances each day (on average), probably due to King Vultures taking 50% fewer flights and spending 40% less time in the air per day. Consistent with these patterns, King Vulture body mass was more than double that of the Greater Yellow-headed Vulture, with a substantially larger hang wing index (a measure of long-distance flight efficiency). At carcasses, Greater Yellow-headed Vultures typically arrived first but were rapidly outnumbered by both King and Black Vultures Coragyps atratus. We find that the movement behaviour of obligate apex scavengers in the western Amazon is linked to their ability to coexist – Greater Yellow-headed Vultures, a smaller stature ‘scouting’ species adapted to fly low, forage early and arrive first at carcasses, are ultimately displaced by larger-bodied, wider ranging King Vultures at large ephemeral carrion resources. Expansion of future GPS tracking initiatives could facilitate the exploration of direct facultative interactions from animal movement data and give further insight into how diverse communities assemble and interact.

Population responses to environmental changes can often vary geographically and between environments, potentially as a consequence of differing niche dynamics. The Eurasian Skylark Alauda arvensis is an open-habitat passerine bird that is declining throughout Europe, mainly due to agricultural intensification. We compared population trends (1992–2021) of the species across three sub-regions of northern Italy characterized by different environmental conditions and human pressures: the Alpine sub-region (less anthropized mountains), the Plain (strongly anthropized and intensively cultivated) and the Oltrepò (less intensively cultivated hills), with changes in the realized Grinnellian niches over three decades. In each sub-region, niche comparisons did not show divergence over the study. However, we found an overall reduction in niche occupancy over time. In the Alpine sub-region, a reduction in niche occupancy in hayfields and pastures was not associated with population decline; indeed, we found an increasing population (+164%), probably because high availability of natural grasslands counteracted niche contraction. Conversely, in the Plain and Oltrepò sub-regions, the observed population declines (−99% and −36%, respectively) are associated with a general reduction of niche occupancy in arable lands that represented the core of the niche in these ranges. In the Plain, the lack of alternative suitable habitats might have limited any opportunity for the species to colonize new environments. Conversely, in the Oltrepò, the less severe population decline is combined with increased niche occupancy in hayfields and pastures at higher elevations. The joint application of population trend analysis and niche modelling as well as the decomposition of population changes across different environmental contexts can contribute to a better understanding of ecological processes affecting population dynamics, supporting policy-makers to implement targeted conservation strategies.

We describe new specimens and species of apodiform birds from the early Eocene London Clay of Walton-on-the Naze (Essex, UK). In addition to multiple partial skeletons of Eocypselus vincenti Harrison, 1984, three new species of Eocypselus are described as Eocypselus geminus, sp. nov., Eocypselus paulomajor, sp. nov. and Eocypselus grandissimus, sp. nov. The previously unknown quadrate of Eocypselus shares a characteristic derived morphology with the quadrate of the Aegothelidae, Hemiprocnidae and Apodidae, whereas the quadrate of the Trochilidae is very different. We also report a striking disparity of the shapes of the axis vertebra of apodiform birds, which is likely to be of functional significance. Eocypselus and extant Hemiprocnidae and Cypseloidini (Apodidae) exhibit the plesiomorphic morphology, whereas a derived shape characterizes extant Aegothelidae, Apodini and Trochilidae. Furthermore, we describe the first partial skeleton of the earliest aegialornithid species, Primapus lacki Harrison & Walker, 1975, which was previously only known from the humeri of the type series that stem from different sites of the London Clay. The apodiform birds from Walton-on-the-Naze show a considerable taxonomic and ecomorphological diversity, and whereas Eocypselus may have inhabited forest edges and caught insects by sallying flights from perches, Primapus probably was a fast-flying and more aerial bird.

Big birding events provide a valuable opportunity to develop datasets to supplement systematic bird monitoring. However, the contributions of these big datasets remain unclear. In this study, we examine two big birding events in Kerala, India (Great Backyard Bird Count and Onam Bird Count). Data submitted during these events between 2014 and 2022 were analysed to assess data quantity, species representation, spatial coverage and birder recruitment. The events contributed a disproportionately large amount of data (12% of all Kerala bird data) and effectively recruited volunteers (> 50% recruited in 2 months) into the citizen science programme. Although the data exhibited a spatial bias (missing 18% of Kerala), the reporting frequencies of common birds from these events were in agreement with the semi-structured birding efforts conducted throughout the rest of the year. The simplicity of their protocols and reasonably high data quality make big birding events a useful component of citizen science. Promoting such events is useful for engaging citizens in bird monitoring and conservation, especially in densely populated and biodiverse countries such as India.

Given the frequency with which translocation is implemented as a conservation tool, remarkably little research has assessed the sustainable management of translocation source populations. We sought to make an a priori estimate of the impact of multiple alternative harvesting scenarios on five passerine species endemic to Norfolk Island which may benefit from future translocation. Population parameters for our five focal taxa were quantified using distance sampling at 298 point surveys conducted in 2019. Intensive nest monitoring between 2018 and 2020 was used to estimate reproductive rates. We modelled population trajectories for all five taxa under alternative harvesting scenarios in forward projections over a 25-year period to assess the likelihood that focal populations could recover from a harvesting event. We used sensitivity analysis to assess the robustness of models to uncertainty around some population parameters. We estimate that Norfolk Island National Park supported 1486 Norfolk Robins Petroica multicolor (95% confidence interval (CI) 1017–1954), 7184 Slender-billed White-eyes Zosterops tenuirostris (95% CI 5817–8551), 2970 Norfolk Grey Fantails Rhipidura albiscapa pelzini (95% CI 2094–3846), 3676 Norfolk Gerygones Gerygone modesta (95% CI 2869–4482) and 1671 Norfolk Golden Whistlers Pachycephala pectoralis xanthoprocta (95% CI 1084–2259) in 2019. All five species were predicted to recover from the harvest of 50, 100 or 150 individuals within 10 years. Despite considerable variation in population parameters, we demonstrate that all five focal taxa have the potential to sustain harvesting at rates required for future conservation translocations. We provide a clear comparison of differing intensity harvesting strategies for on-ground managers. More broadly, we provide a rare example of an a priori assessment of the impact of harvesting for translocation.

Like many other fields, ornithology and birding are addressing their legacy of colonialism, including re-examining their naming practices. Discussions about eponyms, when species are named to honour people, sit at the intersection of nomenclatural stability and social justice concerns. In response to a charged debate about the future of eponymous common names, members of the American Ornithological Society (AOS)'s Diversity and Inclusion Committee held one-on-one listening sessions in 2020 with stakeholder groups across the birding and ornithology community and, in 2021, organized a Community Congress where stakeholders shared thoughts with a public audience. These two events aimed to create spaces for thoughtful dialogue around an inflamed topic and to identify areas of consensus for moving forward. Here we summarize the main findings from these two activities. We found broad agreement among stakeholders that (1) social justice is a valid reason to change names, (2) many issues – especially the technical, decision-making and public-engagement aspects of name changes – need to be considered, and (3) educational opportunities are not only abundant but critical in any name-change process to achieve the stated goals of increasing diversity and belonging in birding and ornithology. Our work highlights the importance of including many voices in conversations when proposed changes to public use systems, such as common names, appear to conflict with current decision-making methods. By creating a space away from knee-jerk reactions, our listening sessions and the Community Congress found that the scientists, birders, educators, data/wildlife managers and field guide authors we spoke with are willing to engage in crucial conversations of how to deal with eponymous common names, as part of engaging with ornithology's colonialist history.

Migrating animals are thought to be important spillover sources for novel pathogens. Haemosporidians (malaria-related parasites) are one such group of pathogens that commonly spillover into novel host communities if competent vectors are present. In birds, shorebirds (sandpipers, plovers and allies) perform some of the longest avian migrations, yet they are traditionally perceived as relatively free from haemosporidians. Although low prevalence fits several theories, such as effective immune responses or low exposure to vectors, few studies have been carried out in freshwater inland sites, where the vectors of haemosporidians (e.g. mosquitoes) are abundant, with a mixture of actively migrating (staging) and breeding hosts. Here we report the prevalence of three haemosporidian parasites, Haemoproteus, Leucocytozoon and Plasmodium, screened in 214 shorebirds from 15 species sampled in a freshwater marshland, southern Belarus. Contrary to most previous studies, we found that haemosporidians were frequent, with an overall prevalence in the community of 16.36%, including the locally breeding shorebirds (23.13%, 134 individuals of 10 species). However, actively migrating shorebirds had much lower prevalence (0.05%, 55 individuals of five species). We suggest that blood parasite infections are more common in shorebirds than currently acknowledged. Yet, actively migrating species may be free from haemosporidians or carry suppressed infections, leading to lower prevalence or even apparent absence in some species. Taken together, we theorize that a combination of sampling biases has driven our understanding of haemosporidian prevalence in shorebirds and future studies should take the migratory status of individuals into account when reporting prevalence. Furthermore, we argue that birds undergoing active migration may be less likely sources of spillover events than previously assumed.

Developing standardized methodology to allow efficient and cost-effective ecological data collection, particularly at scale, is of critical importance for understanding species' declines. Remote camera networks can enable monitoring across large spatiotemporal scales and at relatively low researcher cost, but manually analysing images and extracting biologically meaningful data is time-consuming. Citizen science image analysis could reduce researcher workload and increase output from large datasets, while actively raising awareness of ecological and conservation issues. Nevertheless, testing the validity of citizen science data collection and the retention of volunteers is essential before integrating these approaches into long-term monitoring programmes. In this study, we used data from a Zooniverse citizen science project, Seabird Watch, to investigate changes in breeding timing of a globally declining seabird species, the Black-legged Kittiwake Rissa tridactyla. Time-lapse cameras collected >200 000 images between 2014 and 2023 across 11 locations covering the species' North Atlantic range (51.7°N–78.9°N), with over 35 000 citizen science volunteers ‘tagging’ adult and juvenile Kittiwakes in images. Most volunteers (81%) classified images for only a single day, and each volunteer classified a median of five images, suggesting that high volunteer recruitment rates are important for the project's continued success. We developed a standardized method to extract colony arrival and departure dates from citizen science annotations, which did not significantly differ from manual analysis by a researcher. We found that Kittiwake colony arrival was 2.6 days later and departure was 1.2 days later per 1° increase in latitude, which was consistent with expectations. Year-round monitoring also showed that Kittiwakes visited one of the lowest latitude colonies, Skellig Michael (51.8°N), during winter, whereas birds from a colony at similar latitude, Skomer Island (51.7°N), did not. Our integrated time-lapse camera and citizen science system offers a cost-effective means of measuring changes in colony attendance and subsequent breeding timing in response to environmental change in cliff-nesting seabirds. This study is of wide relevance to a broad range of species that could be monitored using time-lapse photography, increasing the geographical reach and international scope of ecological monitoring against a background of rapidly changing ecosystems and challenging funding landscapes.