Breeding Bird Species Research Articles

Sacred sites provide urban green spaces that maintain bird diversity in the megacity of Tokyo, Japan

Green spaces in cities are thought to play an important role in maintaining urban biodiversity. However, it is difficult to create large new areas of green space in big cities. Therefore, existing green spaces need to be conserved and properly managed to conserve urban biodiversity. In big Japanese cities, sacred sites such as shrines, temples, and historic parks are some of the common types of green space. In addition to their role as religious spaces, they may also play an important role in urban biodiversity conservation because of their function as long-term reserves of natural vegetation. In this study, we examined the function of shrines, temples, and historic parks in Bunkyo ward, Tokyo, in maintaining bird diversity by comparing them with urban parks. In addition, a vegetation survey was conducted to identify environmental factors that affect bird diversity, and differences in the bird species observed in each type of green space are discussed. The heterogeneity of bird species composition between study sites was higher among shrines and temples than among urban parks.Forest bird abundance was higher during the breeding season and bird species richness was higher in winter at shrines and temples and historic parks than in urban parks. Bird diversity was positively affected by the abundance of shrubs and evergreen trees. We found that sacred sites were more important than urban parks for maintaining bird diversity. The results also suggested that differences in vegetation structure are a cause of this pattern, and small green spaces in the grounds of sacred sites are managed in a way that is more suitable for maintaining bird diversity.However, shrines and temples, despite their strong historical and cultural value, are threatened by recent urbanization. It is necessary to maintain and properly manage these green spaces as part of urban ecosystems.

Evaluating urban biodiversity: Effectiveness of citizen science driven species distribution models in urban ecosystems

Citizen science (CS) and remote sensing (RS) approaches have become more reliable, thus providing higher resolution and generating a large amount of environmental data. When considering urban environments, where fragmented and highly diverse landscapes are predominant, the combination of citizen science data and remote sensing techniques with species distribution models (SDM) can play a vital role in comprehensively investigating and evaluating urban biodiversity. However, citizen science derived species distribution models for multiple avian species in dense and fragmented urban areas are rarely used. The study aims (I) to elaborate, whether CS driven SDMs can be effectively used in spatially complex urban environments; (II) to identify biodiversity hotspots and prioritize areas for nature conservation and (III) to examine, if existing protective areas correspond to species’ hotspots. Therefore, Citizen science-based datasets of 26 breeding bird species over three years were obtained for this analysis in Germany’s Ruhr Metropolis. Quality assurance, data thinning, and pseudo-absence simulations were performed. Spatial data from the ecosystem LiDAR project GEDI (Global Ecosystem Dynamics Investigation), climate data from the German Weather Service, and land use information from Copernicus were used as environmental predictors. Eleven different species distri-bution models (SDMs) were trained on species subselection by using Biomod2 for preliminary analysis. Overall model performance was evaluated via several metrics, including TSS (true skill statistics) and ROC (receiver operating characteristic). Finally, four species distribution models were used for ensemble modelling. Subsequently, a species richness analysis was performed with the aim of identifying spots with high avian biodiversity. Overall, the CS-derived SDMs performed well, with high predictive power for all of the investigated species. Within the Ruhr Metropolis, approximately 6% (250 km²) of the terrain was identified as being highly suitable for avian diversity, inhabiting at least 17 out of 26 species. Predominantly within the core urban areas, high species richness was predicted on preserved brownfields and revitalized mine sites, as well as in the remnants of formerly demarcated regional greenbelts. Additionally, regions outside of the core area, which are part of the overarching biotope network framework, proved to have high species richness capabilities for avian biodiversity. These findings aid in optimizing urban development concepts and (sub)urban green space management with respect to urban biodiversity conservation. Following the implications of the recently established Regional Biodiversity Strategy in the Ruhr Metropolis, this analysis demonstrates the importance of networked green spaces, their preservation and the need to close existing network gaps within the Ruhr Metropolis.

Quantifying the effects of landscape and habitat characteristics on structuring bird assemblages in urban habitat patches

Understanding the determinants of biodiversity in fragmented habitats is fundamental for informing sustainable landscape development, especially in urban landscapes that substantially fragment natural habitat. However, the relative roles of landscape and habitat characteristics, as emphasized by two competing frameworks (the island biogeography theory and the habitat diversity hypothesis), in structuring species assemblages in fragmented habitats have not been fully explored. This study investigated bird assemblages at 26 habitat patches (ranging in size from 0.3 to 290.4 ha) in an urban landscape, southwest China, among which habitat type composition and woody plant species composition varied significantly. Through 14 bird surveys conducted over six breeding seasons from 2017 to 2022, we recorded 70 breeding bird species (excluding birds recorded only once and fly-overs, such as raptors, swallows and swifts), with an average of 26 ± 10 (SD) species per patch. We found that patch area had significant direct and indirect effects on bird richness, with the indirect effects mediated by habitat richness (i.e., the number of habitat types). Isolation (measured as the distance to the nearest patch), perimeter to area ratio (PAR), and woody plant richness did not significantly predict variation in bird richness. Furthermore, none of these factors significantly sorted bird species based on their functional traits. However, the overall makeup of bird assemblages was significantly associated with the specific habitat types and woody plant species present in the patches. The results suggest that neither the island biogeography theory nor the habitat diversity hypothesis can fully explain the impacts of habitat fragmentation on bird richness in our study system, with their roles primarily being linked to patch area. The findings that habitat and plant compositions were the major drivers of variation in bird assemblage composition offer valuable insights into urban planning and green initiatives. Conservation efforts should focus not only on preserving large areas, but also on preventing urban monocultures by promoting diverse habitats within those areas, contributing to the persistence of meta-communities.

Diet and Feeding Behavior of the South Polar Skuas Stercorarius maccormicki in the Haswell Islands, East Antarctica

The diet and feeding behavior of South Polar Skuas (Stercorarius maccormicki) are well studied within the species’ breeding range but are poorly understood on the Haswell Islands. The aim of this study was to determine how South Polar Skuas use available resources during the pre-breeding and breeding periods at the Haswell Archipelago (66°31′ S, 93°01′ E, Davis Sea, Southern Ocean) under conditions of prolonged human activity. I studied pellets, spontaneous regurgitation, and stomach contents of feathered birds to study the diet of skuas and used direct observations of their feeding behavior. South Polar Skuas at the Haswell Islands fed primarily on the Emperor Penguin (Aptenodytes forsteri) colony and on terrestrial resources in the Adélie Penguin (Pygoscelis adeliae) and fulmarine petrel colonies. The dominant prey of skuas were breeding Antarctic penguins. Emperor Penguins and Adélie Penguins make up the bulk of the skuas’ diet in the pre-breeding and breeding periods. Surface feeding at sea was observed in the post-breeding period. In recent decades, kitchen waste supported the skua population. Scavenging (placenta and feces of Weddell seals [Leptonychotes weddellii], frozen eggs, chicks and adults of breeding bird species, kitchen refuse) is the dominant strategy for obtaining food. Adélie Penguin eggs and chicks were the main food items of the South Polar Skuas in the Haswell Archipelago. Skua predation could potentially influence the breeding success of Adélie Penguins and fulmarine petrels, but the extent of the impact is unknown. The impact of the South Polar Skua on Emperor Penguins is negligible because skuas feed mainly on frozen chicks and eggs of the species.

Ecological structure of the avifauna composition as a basis for assessment of its heterogeneity and dynamics

The article describes the methodological approach and the results of classification of breeding bird species in Belarus by their preference for habitat type during the breeding season based on this approach. During the classification process, we took into account the preferences developed in the course of evolution, i. e. those that had been the most characteristic of the species before the domination of altered territories and the escalation of an urbanization rate, as well as before many species started living in urban environments on a large scale.In total, we defined six ornithofaunistic complexes (forest, arboreal-shrub, water-coastal, marsh, dry open spaces and synanthropic) that include all 223 bird species that have been observed breeding in Belarus since 2000. In most cases, the ornithofaunistic complexes were further divided into clusters that reflect a prominent ecological differentiation of species, although less drastic than a difference between the complexes themselves. In controversial or debatable cases, to justify attributing a species to a certain ornithofaunistic complex, we compared and analyzed all available data on the occurrence and breeding density of the species. Most breeding bird species belong to forest and water-coastal ornithofaunistic complexes (80 and 64 species, respectively), while only 12 species belong to the ornithofaunistic complex of dry open spaces. This classification proves to be a convenient tool to estimate the size and nature of the changes in the ecological structure of bird assemblages that have undergone some interference or transformations in time as well as to get comparable ecological characteristics of bird populations in different territories.

Winter game crop plots for gamebirds retain hedgerow breeding songbirds in an improved grassland landscape

The cause of recent population declines in some farmland/hedgerow breeding bird species in the UK is related to a lack of cover and food resources in winter. In improved grassland areas some of those declines have been particularly acute and some have been shown to be related to the availability of grass and weed seed in winter. The provision of seed‐bearing crops as part of AES options has been shown to benefit some of these birds. Game crop plots sown on shooting estates for holding and driving gamebirds in autumn and winter have been shown to hold relatively high densities of farmland and wood‐edge birds during the winter.We studied breeding songbirds in hedges in a primarily improved grassland area in the SW of England where there are some large shooting estates that sow relatively large game crop plots (1–5 ha) in the landscape. In this study we found that otherwise similar hedges in terms of size and density near to those winter game crop plots, had between 1.5 and 2 times as many breeding resident songbirds per unit length the following spring compared to hedges further away from game crop plots. This was despite game management in these plots being wound down during February and in many cases, the crops themselves being removed by mid‐March. Hedges within approximately 350 m from game crop plots had more breeding birds. We discuss possible mechanisms and suggest that some passerines preferentially establish breeding territories in hedges near to game crops in late winter. We suggest how to distribute game crop plots to maximise any benefit in an improved grassland landscape.

Michener's group-size paradox in cooperatively breeding birds.

According to Michener's paradox, most altruistic groups in nature should be small and large groups should not exist. This is because per capita productivity is thought to decrease as groups get larger, meaning that the share of indirect fitness available to each group member declines, which favours dispersal. The empirical evidence for a decrease in per capita productivity is contradictory, however, and limited to the social Hymenoptera. I report that per capita reproductive success decreased with increasing group size across 26 cooperatively breeding bird species. Small groups comprising two or three individuals were the most common (79% of 16,101 groups), and these had the highest per capita reproductive success. This close fit between per capita reproductive success and the distribution of group sizes in nature suggests that it may indeed be difficult for large groups to evolve through indirect fitness benefits alone.

Mapping multiscale breeding bird species distributions across the United States and evaluating their conservation applications.

Species distribution models are vital to management decisions that require understanding habitat use patterns, particularly for species of conservation concern. However, the production of distribution maps for individual species is often hampered by data scarcity, and existing species maps are rarely spatially validated due to limited occurrence data. Furthermore, community-level maps based on stacked species distribution models lack important community assemblage information (e.g., competitive exclusion) relevant to conservation. Thus, multispecies, guild, or community models are often used in conservation practice instead. To address these limitations, we aimed to generate fine-scale, spatially continuous, nationwide maps for species represented in the North American Breeding Bird Survey (BBS) between 1992 and 2019. We developed ensemble models for each species at three spatial resolutions-0.5, 2.5, and 5 km-across the conterminous United States. We also compared species richness patterns from stacked single-species models with those of 19 functional guilds developed using the same data to assess the similarity between predictions. We successfully modeled 192 bird species at 5-km resolution, 160 species at 2.5-km resolution, and 80 species at 0.5-km resolution. However, the species we could model represent only 28%-56% of species found in the conterminous US BBSs across resolutions owing to data limitations. We found that stacked maps and guild maps generally had high correlations across resolutions (median = 84%), but spatial agreement varied regionally by resolution and was most pronounced between the East and West at the 5-km resolution. The spatial differences between our stacked maps and guild maps illustrate the importance of spatial validation in conservation planning. Overall, our species maps are useful for single-species conservation and can support fine-scale decision-making across the United States and support community-level conservation when used in tandem with guild maps. However, there remain data scarcity issues for many species of conservation concern when using the BBS for single-species models.

Provisional atlas of breeding birds of Walvis Bay in the coastal Namib Desert


 
 
 In austral summer 2016/17, a provisional bird atlas project was conducted in the town of Walvis Bay (~260 ha), Namibia. In total, 18 breeding bird species were recorded. Four eudominant species (Cape Sparrow, Rock Dove, Laughing Dove, and Common Waxbill) comprised together 65.2% of all breeding birds. Three dominant species – House Sparrow, Southern Masked Weaver, and Speckled Pigeon – comprised additional 23.0%. The community dominance index (DI) was = 0.40, Shannon’s Diversity Index H’ = 2.21, Simpson’s Diversity Index D = 0.87, and Pielou’s Evenness Index J’ = 0.76. By far the most numerous feeding guild were granivores (88.0% of all birds recorded) followed by insectivores (6.0%) and frugivores (5.3%). Tree and/or shrub nesting birds comprised 59.5%, while birds nesting in/on buildings the remaining 40.5%. There were neither ground-nesting nor holenesting birds. Structure-wise, the avian community in the town resembles avian communities in other parts of the world (strong dominance of granivores, such as sparrows and doves). In austral summer 2018/19, a total of 25 marine species were recorded in the lagoon, of which nine (36%) were Palearctic migrant and 16 (64%) African residents. In terms of the number of individuals, Palearctic migrants constituted 17% and African residents 83%. More than half of all marine birds were Greater Flamingos, while the most numerous Palearctic species was the Curlew Sandpiper.
 
 

Effects of human depopulation and warming climate on bird populations in Japan.

Quantifying biodiversity trends in economically developed countries, where depopulation, associated secondary succession, and climate warming are ongoing, provides insights for global biodiversity conservation in the 21st century. However, few studies have assessed the impacts of secondary succession and climate warming on species' population trends at a national scale. We estimated the population trends of common breeding bird species in Japan and examined the associations between the overall population trend and species traits with the nationwide bird count data on 47 species collected from 2009 to 2020. The overall population trend varied among species. Four species populations increased moderately, 18 were stable, and 11 declined moderately. Population trends for 13 species were uncertain. The difference in overall trends among the species was associated with their habitat group and temperature niche. Species with relatively low-temperature niches experienced more pronounced declines. Multispecies indicators showed a moderate increase in forest specialists and moderate declines in forest generalists (species that use both forests and open habitats) and open-habitat specialists. Forest generalists and open-habitat specialists also declined more rapidly at sites with more abandoned farmland. All species groups showed an accelerated decline or decelerated increase after 2015. These results suggest that common breeding birds in Japan are facing deteriorating trends as a result of nationwide changes in land use and climate. Future land-use planning and policies should consider the benefits of passive rewilding for forest specialists and active restoration measures (e.g., low-intensive forestry and agriculture) for nonforest specialists to effectively conserve biodiversity in the era of human depopulation and climate warming.

DNA barcoding reveals cryptic diversification and taxonomic discordance among bats and birds within Sub-Saharan Africa

Cryptic species present a challenge for conservation, as species diversity may remain undetected. In zoological research, DNA barcoding of the mitochondrial cytochrome c oxidase subunit I (COI) has become a useful heuristic tool for aiding species resolution and informing species discovery. Despite concerted efforts to genetically barcode bats and birds, comprehensive assessments have yet to be undertaken across the Afrotropics. We retrieved available DNA barcodes of native breeding Afrotropical bat and bird species. Using Bayesian phylogenetic modelling, we assessed DNA barcode performance at species identification, and sought to detect notable intraspecific clade partitioning hinting at cryptic speciation. Available DNA barcodes represent only 42.3% and 23.6% of the relevant bat and bird species diversity, respectively, with only 18.7% of bat species and 7.2% of bird species having geographically spread records. DNA barcodes afforded greater taxonomic resolution of Afrotropical bird species than of bats (96.8% vs. 84.0%), with bats having a higher proportion of species non-monophyly (25.5% vs. 4.8%). Well-supported (≥ 95% posterior probability) clade partitioning was inferable from twenty-one bat species and fifteen bird species, and a further single under-sampled bat species and fifteen such bird species showed deep (> 2.0%) intraspecific divergences. These phylogenetic signatures allude to cryptic speciation within these volant taxa, and serve to prompt more comprehensive assessments of Afrotropical fauna. These findings also indirectly affirm the importance of paleoclimatic refugia to endemic vertebrate diversity. The current taxonomic status of birds is better supported by this molecular evidence than that of bats.

Local colonisations and extinctions of European birds are poorly explained by changes in climate suitability

Climate change has been associated with both latitudinal and elevational shifts in species’ ranges. The extent, however, to which climate change has driven recent range shifts alongside other putative drivers remains uncertain. Here, we use the changing distributions of 378 European breeding bird species over 30 years to explore the putative drivers of recent range dynamics, considering the effects of climate, land cover, other environmental variables, and species’ traits on the probability of local colonisation and extinction. On average, species shifted their ranges by 2.4 km/year. These shifts, however, were significantly different from expectations due to changing climate and land cover. We found that local colonisation and extinction events were influenced primarily by initial climate conditions and by species’ range traits. By contrast, changes in climate suitability over the period were less important. This highlights the limitations of using only climate and land cover when projecting future changes in species’ ranges and emphasises the need for integrative, multi-predictor approaches for more robust forecasting.

Effect of nature protection and management of grassland on biodiversity – Case from big flooded river valley (NE Poland)

Agriculturally used meadows are habitats whose biodiversity depends on anthropogenic disturbances such as fertilization or mowing. Intensified agricultural practices (too frequent mowing, use of mineral fertilizers and insecticides) lead to declines in the abundance and species diversity of the biota inhabiting them. The intensification of agricultural production in north-eastern Poland relates primarily to the increase in cattle numbers and the intensification of grassland management, but many areas were included in Natura 2000 network. Our study was aimed at indicating the impact of diverse use of meadows on the species richness and diversity of invertebrates, amphibians, and birds in the grasslands of Narew river valley, Special Bird Protection Area, where the intensification of grassland use was noted in the last decades, and part of the meadows was included in the agri-environmental program. The agri-environmental program is a very good tool for the protection of grassland biotic diversity. The highest taxonomic richness and diversity of the studied animal groups were found in meadows included in these programs with extensive use, while the lowest was in the over- and intensively used meadows fertilized with mineral fertilizers and liquid manure. Only the meadows in the agri-environment program were inhabited by the fire-bellied toad and the tree frog - amphibians from Annex IV of the Habitats Directive. The number of breeding bird species globally threatened (IUCN Red List), listed in Annex I of the EU Birds Directive, and with negative population trend in Europe (SPEC1–3) was highest in meadows included in EU conservation programs. The main factors reducing biotic diversity in the grassland of flooded river valley were the high number of grassland mowing per season, intensive fertilization, especially with liquid manure, the great distance of meadows to the river, low soil humidity, and low share of shrubs and trees in the meadows border zone.

Quantifying Transgressive Coastal Changes Using UAVs: Dune Migration, Overwash Recovery, and Barrier Flooding Assessment and Interferences with Human and Natural Assets

The advantages derived from the use of Uncrewed Aerial Vehicles (UAVs) are well-established: they are cost-effective and easy to use. There are numerous environmental applications, particularly when monitoring contexts characterized by rapid morphological changes and high rates of sediment transport, such as coastal areas. In this paper, three different case studies of survey and monitoring with high resolution and accuracy obtained through the use of UAVs are presented; these concern transgressive coastal sites. Results allow for the definition and quantification of coastal landforms and processes, including: (i) The anatomy of a parabolic dune and the rate of landward migration that could interfere with a tourist settlement; (ii) The mode and timing of morphological recovery and realignment of a barrier island overwashed by storm surge episodes; and (iii) The potential flood risk of a progradational spit that is a nesting site of a species of migratory breeding birds of conservation concern. The results demonstrate and confirm that, through a good coupling of drone-sensed quality data and accurate topographic control, quantitative estimates that are useful in assessing the impacts of natural processes involving both human and natural assets can be obtained.

The influence of landscape characteristics on breeding bird dark diversity

The exploration of factors and processes affecting biodiversity loss is central to nature management and wildlife conservation, but only recently has knowledge about the absence of species been recognized as a valuable asset to understand the current biodiversity crisis. In this paper, we explore the dark diversity (species that belong to a site-specific species pool but that are not locally present) of breeding birds in Denmark assessed through species co-occurrence patterns. We apply a nation-wide atlas survey of breeding birds (with a 5 × 5 km resolution), to investigate how landscape characteristics may influence avian diversity, and whether threatened and near threatened species are more likely to occur in dark diversity than least concern (LC) species. On average, the dark diversity constituted 41% of all species belonging to the site-specific species pools and threatened and near-threatened species had a higher probability of belonging to the dark diversity than least concern species. Habitat heterogeneity was negatively related to dark diversity and the proportional cover of intensive agriculture positively related, implying that homogeneous landscapes dominated by agricultural interests led to more absent avian species. Finally, we found significant effects of human disturbance and distance to the coast, indicating that more breeding bird species were missing when human disturbance was high and in near-coastal areas. Our study provides the first attempt to investigate dark diversity among birds and highlights how important landscape characteristics may shape breeding bird diversity and reveal areas of considerable species impoverishment.

Effect of rainfall on the structure and population densities of birds breeding in a suburb of Windhoek, Namibia

A bird community was quantified in the suburb of Olympia (200 ha) in the city of Windhoek, Namibia. Two years (2014 and 2020) were selected to examine the impact of rainfall and sub- urb development on species diversity and population densities of the selected bird species in this community. The total amount of rainfall in Windhoek in 2014 was much higher than in 2020 (475 mm and 275 mm, respectively). In total, 36 breeding bird species were recorded in the study area in 2014 and 2020: 27 spe- cies in 2014 and 31 species in 2020. The number of species com- mon in 2014 and 2020 was 17. The Sörensen’s Similarity Index was therefore rather low (0.59). In overall, population density of 25 selected bird species was much higher in 2020 than in 2014. Population densities of the Laughing Dove, the Southern Masked Weaver, and Chestnut-vented Warbler in 2014 and 2020 were statistically different, whereas population densities of the Red- headed Finch were similar in both years compared.
 The breeding bird community in Olympia suburb does not ap- pear to be stable over years, both in regard to species composition and population densities of particular species. This instability may be linked to constant property development of this suburb and around it. Olympia suburb borders on the periphery of the city, which is a savanna slowly transformed into another suburb. Un- der drought conditions, some species from these surroundings may be attracted to the suburbs by water and food. Hence, con- trary to expectation, densities of some species in the suburbs in the year with low rainfall are higher.

Effects of light and noise pollution on avian communities of European cities are correlated with the species’ diet

Urbanization affects avian community composition in European cities, increasing biotic homogenization. Anthropic pollution (such as light at night and noise) is among the most important drivers shaping bird use in urban areas, where bird species are mainly attracted by urban greenery. In this study, we collected data on 127 breeding bird species at 1349 point counts distributed along a gradient of urbanization in fourteen different European cities. The main aim was to explore the effects of anthropic pollution and city characteristics, on shaping the avian communities, regarding species’ diet composition. The green cover of urban areas increased the number of insectivorous and omnivorous bird species, while slightly decreasing the overall diet heterogeneity of the avian communities. The green heterogeneity—a measure of evenness considering the relative coverage of grass, shrubs and trees—was positively correlated with the richness of granivorous, insectivorous, and omnivorous species, increasing the level of diet heterogeneity in the assemblages. Additionally, the effects of light pollution on avian communities were associated with the species' diet. Overall, light pollution negatively affected insectivorous and omnivorous bird species while not affecting granivorous species. The noise pollution, in contrast, was not significantly associated with changes in species assemblages. Our results offer some tips to urban planners, managers, and ecologists, in the challenge of producing more eco-friendly cities for the future.

The occurrence of a flagship raptor species in intensive agroecosystems is associated with more diverse farmland bird communities: Opportunities for market-based conservation

Traditional livestock systems have supported farmland biodiversity for millennia. However, modern intensive husbandry is challenging wildlife persistence in agroecosystems. We assessed the multiscale determinants of the species richness of breeding bird communities, as well as the occurrence of a flagship raptor species, the lesser kestrel Falco naumanni, in an intensive agroecosystem mostly dedicated to the production of the world-renowned Parmigiano Reggiano cheese. We relied on three avian community richness metrics reflecting a gradient of increasing association with farmed landscapes, i.e. the overall breeding bird species richness, the richness of farmland species, and the richness of ground-nesters (i.e. species that mostly breed within crops) and tested their association with the landscape, agricultural, and pedological variables as well as with lesser kestrel occurrence. We showed that environmental variables determining overall richer avian assemblages did not coincide with those shaping farmland and ground-nesting species richness, thus challenging the potential effectiveness of conservation actions. However, such actions could be optimized by taking into account different spatial scales affecting different species groups. Indeed, landscape heterogeneity, semi-natural/marginal habitats, and a moderate cover of build-up areas enhanced overall species richness at a small spatial scale. At a broader scale, landscape heterogeneity enhanced farmland species richness, whereas fragmentation determined by urbanization negatively affected ground-nesters. Avian community richness metrics were maximized at an intermediate cover of three prevailing crops (winter, summer, and hay crops), increasing when they co-occurred, i.e., in the presence of crop rotation. Lesser kestrel occurrence was associated with richer assemblages of ground-nesting species because this raptor and ground-nesters showed analogous ecological requirements. These findings suggest that the lesser kestrel can be regarded as an ideal flagship for market-based conservation initiatives (e.g., tailored to the production of biodiversity-friendly agri-food products) in intensive agroecosystems since actions aimed at improving the foraging habitats of the species are likely to benefit co-occurring farmland birds of conservation interest.

Decomposing trends in bird populations: Climate, life histories and habitat affect different aspects of population change

AbstractAimDespite the complexity of population dynamics, most studies concerning current changes in bird populations reduce the trajectory of population change to a linear trend. This may hide more complex patterns reflecting responses of bird populations to changing anthropogenic pressures. Here, we address this complexity by means of multivariate analysis and attribute different components of bird population dynamics to different potential drivers.LocationCzech Republic.MethodsWe used data on population trajectories (1982–2019) of 111 common breeding bird species, decomposed them into independent components by means of the principal component analysis (PCA), and related these components to multiple potential drivers comprising climate, land use change and species' life histories.ResultsThe first two ordination axes explained substantial proportion of variability of population dynamics (42.0 and 12.5% of variation in PC1 and PC2 respectively). The first axis captured linear population trend. Species with increasing populations were characterized mostly by long lifespan and warmer climatic niches. The effect of habitat was less pronounced but still significant, with negative trends being typical for farmland birds, while positive trends characterized birds of deciduous forests. The second axis captured the contrast between hump‐shaped and U‐shaped population trajectories and was even more strongly associated with species traits. Species migrating longer distances and species with narrower temperature niches revealed hump‐shaped population trends, so that their populations mostly increased before 2000 and then declined. These patterns are supported by the trends of total abundances of respective ecological groups.Main ConclusionAlthough habitat transformation apparently drives population trajectories in some species groups, climate change and associated species traits represent crucial drivers of complex population dynamics of central European birds. Decomposing population dynamics into separate components brings unique insights into non‐trivial patterns of population change and their drivers, and may potentially indicate changes in the regime of anthropogenic effects on biodiversity.

Taiwan's Breeding Bird Survey reveals very few declining species

Multi-species indicators (MSIs) have been useful tools for reflecting the state of taxa and ecosystems at global, regional, and national levels. However, most indicators are from Europe and North America, and there are few from the world’s major tropical and subtropical biodiversity hotspots, often in large part because of insufficient data availability. We modelled the population trajectories of 107 regularly-occurring breeding bird species in Taiwan (100 native and seven introduced species) and developed MSIs for (i) forest, (ii) farmland, and (iii) introduced bird species based on the Taiwan Breeding Bird Survey dataset between 2011 and 2019. Individual population trajectories for 87 species did not show a significant change, those for 11 species grew significantly, and those for two species declined significantly. All MSIs show significant growth. Based on the phylogenetic generalised least squares (PGLS) results, the forest bird indicator increased somewhat more rapidly than the farmland bird indicator, perhaps reflecting very low rates of deforestation contrasting with more rapid land use change on farmlands in Taiwan. Some of the forest and farmland species, however, showed rapid declines, and most of these atypical decliners were common species or carnivores. Further, the PLGS results show that the introduced species indicator had more rapid growth than native species indicators, posing a potential risk for the integrity of native bird communities in the near future as well as compromising broader ecosystem intactness. Our study provides important information on bird population changes in subtropical Asia. The MSIs will be updated regularly and will be used to provide information to support conservation policies in Taiwan.