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Abstract Feather fouling is a primary cause of seabird mortality during marine hydrocarbon oil spills. Understanding how oils interact with feathers is an important step in mitigating this threat. Seabird feathers from 12 taxa, representing most seabird families from the tropics and southern latitudes, were exposed to crude and condensate oil films under laboratory settings. Feathers were measured for changes in mass proportional to feather size, and for barbule clumping. Seabird feathers from six distinct families exposed to very thin oil sheens (<0.3 μm) showed no significant change in proportional mass relative to control treatments, and 10 of the 12 species exposed to these films revealed no significant difference in barbule clumping. By contrast, exposure to both crude and condensate oil films ≥3 μm resulted in significant increases in feather mass and clumping. Our findings highlight the importance of considering the influence of oil on feather structure when compiling threat assessments involving seabirds. Highlights • Feather fouling is a primary cause of seabird mortality during marine oil spills. • Seabird feathers experimentally exposed to hydrocarbon films of varying thickness. • Feathers showed no significant structural change when exposed to oil sheens <0.3 μm. • Exposure to oil films ≥3 μm led to increases in both feather mass and clumping. • Oil film thickness an important consideration for threat assessments for seabirds. [ABSTRACT FROM AUTHOR]

Determining population trends is critical for conservation. For most bird species, trends are based on count data gathered by institutions with formalized survey protocols. However, limited resources may prevent these types of surveys, especially in developing countries. Ecotourism growth and subsequent increases in opportunistic data from birdwatching can provide a source of population trend information if analyses control for inter-observer variation. List length analysis (LLA) controls for such variation by using the number of species recorded as a proxy for observer skill and effort. Here, we use LLA on opportunistic data gathered by eBird to estimate population trends for 574 North American bird species (48% of species declining) and compare these estimates to population trends based on 1) formal breeding bird surveys (54% of species declining) and 2) population estimates from eBird data controlled using more rigorous correction (46% of species declining). Our analyses show that eBird data produce population trends that differ on average by only 0.4%/year from formal surveys and do not differ significantly from estimates using more control metrics. We find that estimates do not improve appreciably beyond 10,000 checklists, suggesting this as the minimum threshold of opportunistic data required for population trend estimation. Lastly, we show that characteristics affecting a species' ubiquity, such as geographic and elevational range, can affect its population trend estimate. Our results suggest that opportunistic data can be used to approximate species population trends, especially for widespread species. Because our protocol uses information present in all checklists, it can be applied to a diversity of data sources including eBird, trip reports, and bird atlases. [ABSTRACT FROM AUTHOR]

Bioacoustics has become widely used in the study of acoustically active animals, and machine learning algorithms have emerged as efficient and effective strategies to identify species vocalizations. Current applications of machine learning in bioacoustics often identify acoustic events to the species-level but fail to capture the complex acoustic repertoires animals use to communicate, which can inform habitat associations, demography, behavior, and the life history of cryptic species. The penultimate layer of most machine learning algorithms results in a vector of numbers describing the input, called feature embeddings. Here, we demonstrate that the feature embeddings generated by the BirdNET algorithm can enable within-species classifications of acoustic events. First, we successfully differentiated adult and juvenile Great Gray Owls; second, we identified three unique sounds associated with Great Spotted Woodpeckers (series call, alarm call, and drumming). These applications of BirdNET feature embeddings suggest that researchers can classify vocalizations into groups when group membership is unknown, and that within-species grouping is possible even when target signals are extremely rare. These applications of a relatively "black-box" aspect of machine learning algorithms can be used to derive ecologically informative acoustic classifications, which can inform the conservation of cryptic and otherwise difficult to study species. • AI tools can identify many species, but fail to represent animals' repertoires • BirdNET algorithm's feature embeddings enable within-species sound classification • Differentiating species' sounds can improve ecological and conservation research [ABSTRACT FROM AUTHOR]

The role of birds as reservoirs and disseminators of parasites and pathogens has received much attention over the past several years due to their high vagility. Seabirds are particularly interesting hosts in this respect. In addition to incredible long-distance movements during migration, foraging and prospecting, these birds are long-lived, site faithful and breed in dense aggregations in specific colony locations. These different characteristics can favor both the local maintenance and large-scale dissemination of parasites and pathogens. The Iles Eparses provide breeding and feeding grounds for more than 3 million breeding pairs of seabirds including at least 13 species. Breeding colonies on these islands are relatively undisturbed by human activities and represent natural metapopulations in which seabird population dynamics, movement and dispersal can be studied in relation to that of circulating parasites and pathogens. In this review, we summarize previous knowledge and recently-acquired data on the parasites and pathogens found in association with seabirds of the Iles Eparses. These studies have revealed the presence of a rich diversity of infectious agents (viruses, bacteria and parasites) carried by the birds and/or their local ectoparasites (ticks and louse flies). Many of these agents are widespread and found in other ecosystems confirming a role for seabirds in their large scale dissemination and maintenance. The heterogeneous distribution of parasites and infectious agents among islands and seabird species suggests that relatively independent metacommunities of interacting species may exist within the western Indian Ocean. In this context, we discuss how the patterns and determinants of seabird movements may alter parasite and pathogen circulation. We conclude by outlining key aspects for future research given the baseline data now available and current concerns in eco-epidemiology and biodiversity conservation. [ABSTRACT FROM AUTHOR]

The practice of feeding wild birds is a widespread phenomenon, but there has been little consideration of both human and ecological dimensions of the impacts. We used a comprehensive approach to investigate the practice of bird feeding in the unique avian landscape of New Zealand. We quantified the practice and motivations of bird feeding via a nationwide postal survey, and identified ecological risks from current feeding practices. Our study confirmed that, as in many northern hemisphere countries, bird feeding is a common activity in New Zealand, with an estimated 46.6% of households feeding birds. Increased age and dog ownership were strongly associated with participation. Bread was most commonly provided; we estimated 5.1 million loaves/annum across the population of 1.8 million in six surveyed cities. The principal potential risk identified was that introduced birds are likely to be the main consumers of supplementary food sources in New Zealand, which may have follow-on effects for avian community composition. Disease transmission risks were also identified, with poor hygiene practices reported by many respondents. However, the social benefits to humans of feeding birds were strongly reflected in the motivations of the respondents. Over half fed birds because it brought them pleasure. As urbanisation increases globally, opportunities for connecting with nature decrease. Therefore, experiences such as bird feeding that increase the interaction between people and wildlife could be a powerful tool for fostering environmental awareness and guardianship. Our study highlights that without information about ecological consequences, humans may inadvertently make harmful choices for wildlife, so we recommend promulgation of appropriate guidelines to minimise the risks. [ABSTRACT FROM AUTHOR]

Abstract: Birds are among the most widely studied organisms on earth and represent an important indicator group for learning about the effects of climate change – particularly in regard to the effects of climate change on tropical ecosystems. In this review, we assess the potential impacts of climate change on tropical birds and discuss the factors that affect species’ ability to adapt and survive the impending alterations in habitat availability. Tropical mountain birds, species without access to higher elevations, coastal forest birds, and restricted-range species are especially vulnerable. Some birds may be especially susceptible to increased rainfall seasonality and to extreme weather events, such as heat waves, cold spells, and tropical cyclones. Birds that experience limited temperature variation and have low basal metabolic rates will be the most prone to the physiological effects of warming temperatures and heat waves. Mostly unknown species’ interactions, indirect effects, and synergies of climate change with other threats, such as habitat loss, emerging diseases, invasive species, and hunting will exacerbate the effects of climate change on tropical birds. In some models habitat loss can increase bird extinctions caused by climate change by 50%. 3.5°C surface warming by the year 2100 may result in 600–900 extinctions of land bird species, 89% of which occur in the tropics. Depending on the amount of future habitat loss, each degree of surface warming could lead to approximately 100–500 additional bird extinctions. Protected areas will be more important than ever, but they need to be designed with climate change in mind. Although 92% of currently protected areas are likely to become climatically unsuitable in a century, for example only 7 or 8 priority species’ preferred climatic envelopes are projected to be entirely lost from the African Important Bird Area network. Networks of protected areas need to incorporate extensive topographical diversity, cover wide elevational ranges, have high connectivity, and integrate human-dominated landscapes into conservation schemes. Most tropical bird species vulnerable to climate change are not currently considered threatened with extinction, often due to lack of knowledge; systematically and regularly gathering information on the ecology, and current and future distributions of these species is an urgent priority. Locally based, long-term tropical bird monitoring and conservation programs based on adaptive management are essential to help protect birds against climate change. [Copyright &y& Elsevier]

Abstract: Traditional harvesting practices frequently result in simplification of the structure and composition within managed forest stands in comparison to their natural counterparts. In particular, loss of heterogeneity within stands may pose a problem for maintaining biodiversity in perpetuity. In this study, we survey breeding bird diversity and abundance in response to different spatial harvesting patterns in mature red pine forests located on the Chippewa National Forest of northern Minnesota, USA. Treatments are designed to increase structural complexity over time and include three overstory manipulations (dispersed retention, aggregate retention with small gaps, and aggregate retention with large gaps), one understory manipulation (brush removal), and controls (no harvesting, and/or no brush removal). In 2003, the first breeding season following the harvest, we found little difference in bird community composition between control and treatment stands. In 2005, the third breeding season following harvest, avian abundance, richness, and diversity were all greater within treatments. Species associated with edge, shrub, and early successional habitats generally show positive response to treatments (e.g. Chestnut-sided Warbler [Dendroica pensylvanica], Mourning Warbler [Oporornis philadelphia], Chipping Sparrow [Spizella passerine]), as do some species associated with mature forest (e.g., Pine Warbler [Dendroica pinus], Rose-breasted Grosbeak [Pheucticus ludovicianus]). Ovenbirds (Seiurus aurocapilla) and Black-throated Green Warblers (Dendroica virens) were more abundant in control stands. There are, as of yet, no discernable differences in avian community composition among the three overstory treatments or between the single understory treatment and the understory control, but differences are expected as the treatments diversify due to understory development. While overstory retention harvests provide habitat for a diverse and abundant bird community, the temporal divergence in avian community composition that we observed between treatment and control stands reveals the importance of uncut, mature red pine forest as a component of a biodiverse landscape. [Copyright &y& Elsevier]

Abstract: Animal geography has created a ‘new’ look at animal–human relations, incorporating the shared subjectivities of jointly ‘actant’ behaviour. This approach is particularly relevant to urban geographies of avian presence, given the increased intensity of human habitation, with birds as the commonest and most mobile urban animals. The inter- and intra-species, competitive foraging of three bird species in Glasgow, and the shared reactions between the birds and humans is examined using an animal geography and urban ecological approach. The animal geography approach, emphasising bird–human actant interactions, supported by a rigorous, positivist ecology, enables a more informed assessment of urban biogeography and conservation possibilities. [Copyright &y& Elsevier]

Abstract: The effect of urbanization can be immense, yet our understanding is rudimentary. Here, we compile the most recent information on urban impacts on avian populations and communities. Compared to other vertebrates, birds are easily monitored by skilled observers and provide a mechanism to explore urban effects and responses to different urban designs. Taxonomically, bird communities in distinctly different habitats are most different in the least disturbed sites and the most similar in the most urbanized sites. Urbanization tends to select for omnivorous, granivorous, and cavity nesting species. Increased urbanization typically leads to an increase in avian biomass but a reduction in richness. Unlike most passerines, raptors may have home ranges that extend beyond the urban boundary and therefore do not need to meet all their ecological requirements within urban areas. Urban habitats are often of superior quality to raptors because there they are often free from persecution and have an adequate food supply. The processes that underlie the patterns of population and community level responses need more attention, but several areas of have been identified as being important. Birds respond to vegetation composition and structure, and urban areas that retain native vegetative characteristics retain more native species than those that do not. Avian fecundity in urban areas is a reflection of species-specific adaptability to urban resources, and to levels of nest predation and nest parasitism. Additionally, non-consumptive human activities that increase with urbanization are recognized as having negative impacts on avian populations and communities. Avian survivorship in urban areas is influenced by risk of collision with man-made objects, changes in the predator assemblage, food supply, and disease. Missing are thorough investigations in the regions of highest human population growth, e.g. Southeast Asia. Additionally, there is a paucity of information from regions of high avian diversity, e.g. tropical forests. Clearly, local knowledge and study is required before implementation of management policies to reduce urban impacts on bird communities. Hopefully, such policies will include long-term monitoring. Demographic parameters of fecundity and survivorship need to be examined in conjunction with measures of community diversity and density across the urban gradient to better understand the quality of different urban habitats, and the variation of quality among spatial patterns of urbanization within the native habitat matrix. [Copyright &y& Elsevier]

From 1995 to 1999, we mist-netted birds in regenerating clearcuts within a primarily forested landscape of West Virginia and Virginia to determine the extent that both resident and migrant birds and their young use this type of early-successional habitat during the post-fledging period. Our primary objective was to document whether or not birds typically considered mature or late-successional forest breeders were present in the clearcuts and if they were there with their young. Four mist-nets were located in each of six different forest clearcuts ranging in age from 1 to 7 years post-cut (at time of study initiation) and in size from 8.2 to 13.4 ha. We caught 613 adult birds and 206 juvenile birds of 46 different species within these six different sites. Species typically associated with mature forest, such as the Worm-eating Warbler (Helmitheros vermivorus), Red-eyed Vireo (Vireo olivaceus), Black-and-white Warbler (Mniotilta varia), Wood Thrush (Hylocichla mustelina), and Ovenbird (Seiurus aurocapillus) were among the most commonly captured (adults, juveniles, and family groups). Seven Worm-eating Warblers originally color-banded on territories in adjacent mature forest were recaptured in clearcuts during the post-fledging period, four with dependent young. Although it was apparent that both the adults and young of species of forest-interior breeders were using regenerating clearcuts during the post-fledging period, we are unsure as to the exact reasons why, and, more importantly, whether these habitats enhance their survival. [Copyright &y& Elsevier]

• Birds are a diverse class that significantly respond to ecological changes and urbanization. • Native bird species richness was positively related to vegetative cover, and negatively to urbanization. • Generalist bird species, adapted to urbanization, were more common around settlements. • There was a strong relationship between Riparian Quality Index (RQI) and bird richness. • Increasing RQI values with restoration will benefit avian diversity in urban areas. Civilization built around rivers directly affects riparian corridor structure and ecology. Degradation, pollution, and deterioration along riparian corridors in urban landscapes change species composition and biodiversity. Birds are one of the most vulnerable taxa to ecological changes. The main objective of our study was to spatially compare bird species richness, abundance, and community structure along the Asar River, an urban riparian corridor in Düzce, Turkey. We identified 63 bird species, comprising 6722 individuals, and classified them into one of three groups: generalist species (11 species), woodland species (40 species), and waterbird species (12 species). Bird species richness was positively related to vegetative cover and negatively to urbanization. Richness was low in the winter and was higher during spring and summer. Riparian Quality Index (RQI) scores (mean = 54.8 ± 33.7; max. = 97 and min. = 5) were relatively low for all sampling plots and was reduced by human activities (e.g., roads, farmland, settlement). The number of woodland bird species changed positively (r = 0.71) with RQI. The generalist bird species, adapted to urbanization, were more common around settlements and open areas. Human population and settlement around Asar River increased one-third and farmland and natural habitat decreased one-fifth during the last decade. The area has high potential for growth and increased urbanization, thus increasing the pressure on the natural areas. Activities that diminish the amount of tree cover in the riparian corridor should be avoided. Habitat restoration and rehabilitation will increase RQI values, which can be used as indicators for bird richness in urban landscapes and benefit avian diversity along the riparian corridor. The existing riparian corridor and any enhancements to the corridor will help conserve Düzce's biodiversity in the future. [ABSTRACT FROM AUTHOR]

Systematic monitoring of species across their geographic ranges is a critical part of conservation but it is resource-intensive, costly, and difficult to organize and maintain in the long-term. Large-scale community science programs like eBird may improve our ability to monitor bird populations, particularly in tropical regions where formal studies are lacking. Here, we estimated population trends for nearly 9000 bird species using global eBird birdwatching data and compared our trends to the population trends designated by BirdLife International. We calculated the rate of agreement between eBird and BirdLife trends and examined the effects of latitudinal affiliation, threat status, number of eBird checklists, eBird trend, BirdLife trend and BirdLife trend derivation on the rate of agreement. We also used a randomization approach to compare observed rates of agreement with the rates of agreement expected by chance alone. We show that the rate of agreement was marginally better than expected by chance and improved significantly for temperate region species of Least Concern with more checklists, and species that eBird or BirdLife identified as increasing. Our results suggest that eBird data are not currently adequate for monitoring populations of the majority of the world's bird species, especially in the developing world where systematic surveys are essential. Increased local participation in community science initiatives like eBird may improve our ability to effectively monitor species. Furthermore, it is important to assess the accuracy of BirdLife trends and the manner in which they are derived, especially for species where BirdLife and eBird data trends disagree. • Community science programs may improve our ability to monitor world bird populations. • We use data from eBird to estimate population trends for 9000 bird species. • We compare these trends (increasing, stable or decreasing) with those of BirdLife. • Overall, eBird trends were marginally better than expected by chance. • Agreement improved for common, temperate and increasing species of Least Concern. [ABSTRACT FROM AUTHOR]

Accurate and robust population monitoring is essential to effective biodiversity conservation. Citizen scientists are collecting opportunistic biodiversity records on unprecedented temporal and spatial scales, vastly outnumbering the records achievable from structured surveys. Opportunistic records may exhibit spatio-temporal biases and/or large heterogeneity in observer effort and skill, but the quantity-quality trade-offs between surveys and less structured schemes remain poorly understood. Recent work has advocated the use of simple trend models for opportunistic biodiversity records. We examine the robustness of population trends of common United Kingdom birds derived from two citizen-science schemes; BirdTrack, an opportunistic recording scheme, and the structured Breeding Bird Survey (BBS). We derived reporting rate trends from BirdTrack lists using simple statistical models which accounted for list-level effort covariates but not for preferential sampling, and compared them to abundance and occurrence trends derived from BBS survey data. For 90 out of 141 species, interannual changes in reporting rates were positively correlated with trends from structured surveys. Correlations were higher for widespread species and those exhibiting marked population change. We found less agreement among trends for rarer species and those with small or uncertain population trajectories. The magnitude of long-term changes in reporting rates was generally smaller than the magnitude of occupancy or abundance changes, but this relationship exhibited wide scatter, complicating the interpretability of reporting rate trends. Our findings suggest that simple statistical models for estimating population trends from opportunistic complete lists are robust only for widespread and common species, even in a scheme with many observers and extensive coverage. [ABSTRACT FROM AUTHOR]

Biodiversity science and conservation alike require environmental indicators to understand species richness and predict species distribution patterns. The Dynamic Habitat Indices (DHIs) are a set of three indices that summarize annual productivity measures from satellite data for biodiversity applications, and include: a) cumulative annual productivity; b) minimum annual productivity; and c) variation in annual productivity. At global scales and in temperate regions the DHIs predict species diversity patterns well, but the DHIs have not been tested in the tropics, where higher levels of productivity lead to the saturation of many remotely sensed vegetation indices. Our goal was to explain bird species richness patterns based on the DHIs in tropical areas. We related the DHIs to species richness of resident landbirds for five guilds (forest, scrub, grassland, generalist, and all resident birds) based on a) species distribution model (SDM) maps for 217 species, and b) range map for 564 species across Thailand. We also quantified the relative importance of the DHIs in multiple regression models that included two measures of topography, and two climate metrics using multiple regression, best-subsets, and hierarchical partitioning analyses. We found that the three DHIs alone explained forest bird richness best (R 2 adj 0.61 for both SDM- and rangemap based richness; 0.15–0.54 for the other guilds). When combining the DHIs with topography and climate, the richness of both forest birds and all resident bird species was equally well explained (R 2 adj 0.85 and 0.67 versus 0.81 and 0.68). Among the three DHIs, cumulative annual productivity had the greatest explanatory power for all guilds based on SDM richness maps (R 2 adj 0.54–0.61). The strong relationship between the DHIs and bird species richness in Thailand suggests that the DHIs capture energy availability well and are useful in biodiversity assessments and potentially bird conservation in tropical areas. • We tested the Dynamic Habitat Indices (DHIs) versus bird richness across Thailand. • Richness was based on distribution models (217 species) and IUCN range maps (564). • The three DHIs predicted forest bird richness best. • Together with climate and topography, all resident richness were also well predicted. • The DHIs capture biodiversity-relevant productivity in tropical areas well. [ABSTRACT FROM AUTHOR]