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Radar is a powerful technology for surveys of avian movements. Validating the accuracy of radar detection is essential when establishing quantitative criteria for tracking bird trajectories and counting bird flocks. This study clarifies the positional and biological factors influencing the probability of detection (POD) and echo size on X-band marine radar. The bird trajectory for validation was obtained by ornithodolite at the same time as the radar scan. Distance was found to have a negative effect on POD and echo size, while elevation angle positively affected POD. Body mass and flock size positively affected POD and echo size. In predicting detection performance, the survey distance required to achieve 50% POD was 750 m or less for Grey-faced Buzzard, the lightest target species, but up to 1800 m for a pair of Bewick's Swan. Our study provides survey and analysis procedures that allow for efficient validation using ornithodolites. Then, we identify the range settings that should be considered for target species and contribute to establishing criteria for quantitative radar bird surveys. [ABSTRACT FROM AUTHOR]

The very large demand for songbirds in Indonesia undermines the efforts of the Government of Indonesia to regulate and control harvest and trade. As more species become increasingly rare, new species are sought after and included in the trade to supply demand from hobbyists, traders and songbird competition participants. One such group of species is the butcherbirds. Four species of butcherbirds are native to Indonesia and prior to 2016 these birds were hardly found in trade. Since then, the trade has grown rapidly and during 57 surveys of bird markets in 12 cities on Java, Bali and Lombok, we recorded 235 butcherbirds. We found 43 advertisements online offering butcherbirds for sale. The highest numbers were recorded in the easternmost cities we surveyed (Mataram, 11.5 birds/survey; Denpasar 9.0 birds/survey) and we recorded higher numbers of butcherbirds for sale nearer to their natural distribution range. Compared to other species, butcherbirds command high prices (hooded butcherbird: US$185; black butcherbird: US$122). Despite the authorities attempting to regulate the exploitation of butcherbirds with annual harvest and trade quotas (set at zero for 2022), the trade evidently is challenging to control and may pose a threat to the conservation of these species in the wild. [ABSTRACT FROM AUTHOR]

The effectiveness of surveys of breeding birds varies due to multiple factors, with the primary being imperfect detection, which is particularly severe for elusive species. For example, the territory mapping method requires surveying an area multiple times a season to compensate for missing individuals during single surveys. Novel methods require much less effort in the field and include estimation of both detection probability and abundance corrected for individuals that went undetected. The aim of this study was to check if point counts and model-based results provide estimates similar to the ones from the territory mapping method. We studied the abundance of two forest birds—Goldcrest Regulus regulus and Firecrest R. ignicapilla—on three permanent census plots in the Białowieża Forest (E Poland). We compared abundance estimates resulting from the territory mapping method in its 'standard' (~ 10 visits) and intensive (~ 20 visits) approaches. We also performed point counts at the same plots using distance sampling methodology and hierarchical models in an attempt to get unbiased estimates by correcting for imperfect detection. We found that the standard territory mapping method produces much lower abundances than model-based estimates, which was particularly evident for the more numerous Firecrest. At the same time, results from point counts were more consistent with numbers from the intensive territory mapping. Our findings suggest that applying point counts and distance sampling models meet modern standards by considering various effects in abundance, availability and detection processes along with providing uncertainty of their estimates. We assume that our results might be applicable to other elusive species. [ABSTRACT FROM AUTHOR]

As the Arctic becomes increasingly accessible to the resource extraction industry, an understanding of the impacts of infrastructure and anthropogenic disturbance on tundra-nesting avian populations is critical. We conducted breeding bird surveys using point counts and Program for Regional and International Shorebird Monitoring (PRISM) rapid surveys at the Hope Bay Project, an underground gold mine in Nunavut, Canada, from 2007 to 2015. We examined the relationship between abundance of total birds, songbirds, and shorebirds with distance from infrastructure, anthropogenic disturbance (i.e., activity at the mine site), and environmental covariates. Contrary to our predictions, anthropogenic disturbance showed no significant effect on bird abundance for either survey type or bird grouping. However, total bird abundance was associated with distance from infrastructure for both survey methods. A relationship with distance to infrastructure, with variability in influence, was also present for songbird point count data and shorebird PRISM data, but was not significant for songbirds recorded during PRISM surveys. Habitat type played a vital role in determining avian abundance, with PRISM surveys showing that wet lowland ecotypes supported higher bird numbers, whereas point count data revealed a more nuanced habitat association, likely reflecting the specific habitat preferences of different songbirds. Our study highlights the need for strategic planning of industrial development, incorporating comprehensive monitoring and ensuring the protection of preferred Arctic-breeding bird habitats. By aligning development projects with environmental objectives, we can ensure the coexistence of industrial interests and the future of avian populations in the Arctic. [ABSTRACT FROM AUTHOR]

The fast conversion of natural habitats into cities is a worldwide environmental change, negatively affecting ecosystem processes and functioning. Understanding how changes in taxonomic richness and composition are associated with the reduction in functional traits and evolutionary history in different levels of urbanization is important to minimize the impacts of urban landscapes on ecological communities. We investigated the effect of anthropogenic predictors on taxonomic, functional, and phylogenetic diversity of bird communities along the urbanization gradient of a South American city. We surveyed birds and collected data on patch size, isolation, and noise from 43 patches classified as natural (n = 13), suburban (n = 22), and urban (n = 8). We analyzed how anthropogenic factors affect patch diversity (richness) and composition (similarity among patches) in terms of taxonomic, functional, and phylogenetic diversities. We found that suburban patches had higher functional richness and that these patches had species and phylogenetic history that are typically present either in urban or natural areas. Further, we found that noise reduced taxonomic and phylogenetic richness, contributing to changes in species composition and diversity loss in highly urbanized patches. Although some species can be highly sensitive to human impacts, suburbs have less intense anthropogenic activities (e.g. traffic) maintaining higher functional diversity and likely ecosystem functioning than urban areas. Our results suggest that cities can protect biodiversity if we reduce urban noise and maintain green areas, as commonly observed in the suburbs. [ABSTRACT FROM AUTHOR]

The coastal wetlands of northern Chilean Patagonia are relevant sites for the conservation of migratory waterbirds. The aim of this paper is to compare different marine coastal wetlands to identify which factors influence the structure of bird assemblages. Sediment samples were collected, and the birds were surveyed in four wetlands: Chullec, Curaco de Vélez and Quinchao on Quinchao Island, and Putemún on Chiloé Island in 4 seasonal sampling campaigns. The composition of the sediment did not change during the year, with a predominance of sandy sediments except in Putemún where gravel dominates. The size of the sediment particle decreased from the upper (0 to 30 m) to the lower (100 m) intertidal. The abundances of benthic organisms varied between intertidal levels in all wetlands and seasonally in Chullec and Curaco de Vélez, being lower during warm seasons. Thirty-four species of birds were recorded with Anatidae, Laridae and Scolopacidae showing the highest species richness. A principal component analysis clustered the wetlands of Quinchao Island and the variables that account for 35.8% of the variance are sandy sediments, the presence of Scolopacidae, Laridae, Furnariidae and Haematopodidae among birds and Polychaeta, Malacostraca and Enopla in the benthos. In the wetlands of Quinchao Island there was a relationship between the composition of the sediment, distribution, and type of benthic communities with the presence of some bird taxa. The bird assemblages change seasonally and were similar to each other during warm seasons, probably due to the availability of food for migratory birds and sediment characteristics. [ABSTRACT FROM AUTHOR]

Climate change remains one of the most urgent challenges for biodiversity conservation. Recent studies have highlighted that climate extremes (CLEXs) can lead to widespread and negative effects across all taxa and ecological levels, but most of these studies are based on short-term periods and small spatial scales and lack a multi-species approach. Here, using generalised additive models (GAMs) and the UK Breeding Bird Survey (BBS), we described response curves for the abundance of 100 resident bird species over large spatial and temporal scales and identified the species showing a greater sensitivity to CLEXs. We used five climatic indices computed at 1-km spatial resolution as proxies of CLEXs during the winter or breeding season and considered both 1- and 2-year lagged effects. The results demonstrated widespread and significant effects of CLEXs on bird abundances at both time lags and in both seasons. Winter frost days (FD0), summer days (SU25) during the breeding season and simple precipitation intensity index (SDII) during the breeding season mainly showed negative effects. Daily temperature range (DTR) in both winter and breeding season and dry days (DD) during the breeding season led to diversified responses across the species, with a prevalence of positive effects. A large proportion of species showed a high sensitivity to CLEXs, highlighting that these species may deserve attention in future studies aimed at biodiversity conservation. We demonstrated that CLEXs can represent a significant driver affecting population abundances over large spatial and temporal scales, emphasising the need for understanding mechanistic processes at the basis of the observed effects. [ABSTRACT FROM AUTHOR]

Savanna ecosystems are maintained by fires with a fire-adapted biota, and savannas occur in Amazonia in patches surrounded by tropical forest. Different fire regimes can generate structurally diverse vegetation, and the composition of savanna bird assemblages is known to be closely related to vegetation structure. However, long-term approaches and interaction of fire with other environmental factors need to be explored for the better understanding of the effects of fire on birds. In an Amazonian landscape composed by savanna and forest, we investigated the effects of different fire regimes in a 12-ha area in three periods through 23 years. We also examined the effects of frequency and extent of fires, tree cover, and distance to forest on bird composition in twelve 3.7-ha savanna plots. Birds were surveyed with mist-nets and species were classified as to their habitat use by their frequency of registers in forest and savanna plots in visual/acoustical surveys. After 13 years without fire, many forest species colonized the area and some savanna species were lost. After one fire event in a plot that had not burned for 12 years, some savanna species returned. These results highlight the effects of fire regime on birds and indicate that many savanna bird species depend on the occurrence of regular fires. [ABSTRACT FROM AUTHOR]

The coastline of Argentine Patagonia in the Southwest Atlantic provides highly productive habitats for a variety of aquatic birds. Both resident birds and migratory birds coming for wintering from the high arctic tundra, converge in these wetlands for resting and feeding, which favours parasite transmission. In the course of helminth diversity survey in Patagonian birds, we found a new digenean species belonging to the genus Parorchis (Philophthalmidae). Herein, we describe its complete life cycle and provide the morphological description accompanied by DNA sequence data. Adult specimens were obtained from the resident Kelp Gull Larus dominicanus (Laridae), and Nearctic migratory shorebirds, the Baird's Sandpiper Calidris bairdii and the White-rumped Sandpiper Calidris fuscicollis (Scolopacidae). Rediae of the new species were found in the muricid gastropod Trophon geversianus (Muricidae), whose distribution is restricted to the intertidal and subtidal marine south coasts of Argentina and Chile. Sequences of complete ITS and partial 28S regions confirmed the conspecificity of the rediae from T. geversianus and adults specimens recovered from L. dominicanus and C. fuscicollis. Cercariae emerge from these molluscs and quickly encyst on the substrate including surfaces of the mollusc itself; shorebirds become infected by eating snails. We examine phylogenetic affinities of the new species using partial 28S sequences. Our analysis placed the new species in a clade with other Parorchis spp., which also use muricid gastropods as intermediate hosts. This study contributes to the knowledge of the diversity of marine trematodes in the subpolar region of South America. [ABSTRACT FROM AUTHOR]

Urbanization requires enormous amounts of material inputs especially sand to fulfilling the demands of the increasing human population through sand mining. It has negative environmental impacts in terms of physical, chemical, and biological aspects like river-associated biodiversity, especially on river dolphins, fishes, crocodiles, turtles, otters, and birds. The temporary sand islands of Rivers with their abundant food supplies for birds are ideal nesting grounds for a variety of avian species, like Indian Skimmer, Black-bellied Tern, River Tern, Great Thick-knee, and River Lapwing. Extensive sand mining is degrading the breeding grounds of these sandbar nesting birds which can eventually lead to their population decline. Inadvertent erosion of river beds and banks also may occur as a result of extreme extraction practices. The use of heavy machinery is also affecting the collective environment. Conservation priority areas can be identified using select birds as environmental indicators and model organisms for biodiversity conservation. Long-term avifaunal survey data could also be useful for effective monitoring of the changes in the riverine habitat quality and biodiversity. Increasing natural riparian vegetation and conservation awareness among local people could make a positive impact on conserving these habitats along with some of the threatened avian species. [ABSTRACT FROM AUTHOR]

Citizen science, including structured and semi-structured forms, has become a powerful tool to collect biodiversity data. However, semi-structured citizen science data have been criticized for higher variability in quality, including less information to adjust for imperfect detection and uneven duration that bias the estimates of species richness. Species richness estimators may quantify bias in estimates. Here, we test the effectiveness of Chao1 estimator in eBird (semi-structured) by comparing it to averaged species richness in Breeding Bird Survey Taiwan, BBS (structured) and quantifying bias. We then fit a power function to compare bias while controlling for differences in count duration. The Chao1 estimator increased the species richness estimates of eBird data from 56 to 69% of the average observed BBS and from 47 to 59% of the average estimated BBS. Effects of incomplete short duration samples and variability in detectability skills of observers can lead to biased estimates. Using the Chao1 estimator improved estimates of species richness from semi-structured and structured data, but the strong effect of singleton species on bias, especially in short duration counts, should be evaluated in advance to reduce the uncertainty of estimation processes. [ABSTRACT FROM AUTHOR]

We propose an extension of the N-mixture model that enables the estimation of abundances of multiple species as well as the correlations between them. Our novel multi-species N-mixture model (MNM) is the first to address the estimation of both positive and negative inter-species correlations, which allows us to assess the influence of the abundance of one species on another. We provide extensions that permit the analysis of data with excess of zero counts, and relax the assumption that populations are closed through the incorporation of an autoregressive term in the abundance. Our approach provides a method of quantifying the strength of association between species' population sizes and is of practical use to population and conservation ecologists. We evaluate the performance of the proposed models through simulation experiments in order to examine the accuracy of both model estimates and coverage rates. The results show that the MNM models produce accurate estimates of abundance, inter-species correlations and detection probabilities at a range of sample sizes. The MNM models are applied to avian point data collected as part of the North American Breeding Bird Survey between 2010 and 2019. The results reveal an increase in Bald Eagle abundance in south-eastern Alaska in the decade examined. [ABSTRACT FROM AUTHOR]

Partial migration is one of the most widespread migratory strategies among taxa. Investigating the trade-off between environmental/social factors — fitness and energetic consequences — is essential to understand the coexistence of migratory and resident behaviours. Here, we compiled field monitoring data of wintering population size and telemetry data of 25 migrant and 14 resident Egyptian Vultures Neophron percnopterus to analyse how environmental and social factors modulate overwintering immature population size, compare energetic consequences between migratory and resident individuals across wintering and non-wintering seasons and evaluate fitness components (i.e. survival and reproduction) between the two migratory forms. We observed that social attraction may influence the number of overwintering immature individuals, which increased linearly with adult birds surveyed. Residents spent more energy but exhibited higher survival probabilities and lower breeding activity. On the contrary, migratory birds showed lower energy expenditure during winter but also lower survival and more breeding attempts. These results suggest that social attraction may modulate population dynamics and promote residency in immature birds. Resident individuals benefit from enhancing their survival at the expense of higher energy expenditure during winter. Migrant birds, on the contrary, may compensate for the higher costs in terms of survival by a reduction in the energy cost, which may benefit more frequent breeding. Our results offer new insights to understand how species benefit from one strategy or another and that the coexistence of both migratory forms is context-dependent. Significance statement: Animal populations exhibiting partial migration are composed of migrant and resident individuals who share the same breeding areas but different overwintering quarters. Deciphering the causes and consequences that affect each migratory behaviour is essential to understand the balance and persistence of the two strategies. Here, we investigate the environmental and social factors affecting number of immatures during winter and evaluate both migratory strategies in terms of energy expenditure, reproduction and survival. We found that social attraction modulates wintering population size of immature individuals and that the residency is energetically more costly but beneficial in terms of survival but not for breeding. By contrast, migration lessens the energy costs, increases the breeding activity, but also reduces survival probability. [ABSTRACT FROM AUTHOR]

Protected areas are a cornerstone for biodiversity conservation, and typically support more natural and undisturbed habitats compared to unprotected lands. The effect of protected areas on intra-specific ecological niche has been rarely investigated. Here, we explore potential differences in ecological niche properties of birds and mammals across protected and unprotected areas, and relate such differences to species traits. We combine two decades of survey data of birds and mammals from protected and unprotected areas, and apply robust matching to obtain a set of environmentally comparable protected and unprotected sites. Next, we calculate intra-specific niche volume change and habitat shift between protected and unprotected areas, and use generalized linear mixed models to explain these responses with species traits (habitat specialization, body mass, diet, and red list status). The majority of bird and mammal species (83% and 90%, respectively) show different habitat use when occurring within and outside protected areas, with the magnitude of this shift highly varying across species. A minority of species (16% of birds and 10% of mammals) do not change their niche volume nor shift their habitat between protected and unprotected areas. Variation in niche properties is largely unrelated to species traits. Overall, the varying ecological niche responses of birds and mammals to protected areas underscore that there is no universal niche-based response, and that niche responses to land protection are species-specific. [ABSTRACT FROM AUTHOR]

Globally, saline lakes occupy about 23% by area, and 44% by volume. Importantly, these lakes might desiccate by 2025 due to agricultural diversion, illegal encroachment, or modify due to pollution, and invasive species. India's largest saline lake, Sambhar is currently shrinking at a phenomenal rate of 4.23% every decade due to illegal saltpan encroachments. This study aims to identify the trend of migratory birds and monthly wetland status. Birds' survey was conducted for 2019, 2020 and 2021, and combined it with literature data of 1994, 2003, and 2013, for understanding their visiting trends, feeding habits, migratory and resident birds ratio, along with ecological diversity index analysis. Normalized Difference Water Index (NDWI) was scripted in Google Earth Engine. Results state that lake has been suitable for 97 species. Highest NDWI values was 0.71 in 2021 and lowest 0.008 in 2019. Notably, the decreasing trend of migratory birds coupled with decreasing water level indicates the dubious status for its existence. If these causal factors are not checked, it might completely desiccate. Authors recommend a few steps that might help conservation. Least, the cost of restoration might exceed the revenue generation. [ABSTRACT FROM AUTHOR]

Background: Agroforestry is an integrated land-use system that plays a great role in the conservation of landscape biodiversity. The study aimed to assess the composition and diversity of avian species along with different habitat types of agroforestry in Kibet Town, Southern Ethiopia. Methods: Four habitat types of agroforestry system which are home gardens, live fences, parkland, and eucalyptus woodlot were identified. Line transects were used for bird surveys. The Shannon diversity index (H′) and species evenness index (E) were used to compare diversity among habitat types. A similarity percentages (SIMPER) test was carried out to identify the main species and feeding guild that typified each habitat type. The overall significance was assessed with the ANOSIM test using PAST (version 4.03). Results: A total of 50 bird species belonging to 28 families and 10 orders were recorded. Order Passeriformes (67.3%) had the highest number of species. Bird community composition differed among habitat types. The dissimilarity was mainly due to White-browed robin-chat (Cossypha heuglini), Streaky seed-eater (Serinus striolatus), Village Weaver (Ploceus cucullatus), African Paradise-Flycatcher (Terpsiphone viridis), and Black-Headed Paradise Flycatcher (T. rufiventer). The finding also revealed that insectivore was the dominant feeding guild. Conclusions: The present study shows evidence that more insectivore bird species use different types of agroforestry as habitat and foraging sites. So, any concerned bodies who have engaged in avian conservation should give special consideration to this modified landscape. [ABSTRACT FROM AUTHOR]

Context: Nomadism is a movement strategy in response to non-seasonal environmental variability. Knowledge of nomadic species movements is poor but is necessary to understand life histories and develop appropriate conservation strategies. Objectives: We provide a first quantification of nomadism among Australia's arid bird community, which is presumed to be highly nomadic, by measuring variation in species' occurrence and abundance among years to determine whether there are clear nomadic and non-nomadic strategists. Methods: We surveyed birds annually from 2012 to 2016. We measured how many years each species was present at a site and estimated inter-annual variability in species abundance, using both measures to infer species movement patterns. We used results to inform existing movement classifications. Results: Most arid species showed low site persistence, with species detected at the same site, on average, 1.8 out of the five survey years. Movement varied along a continuum rather than grouping into distinct nomadic and non-nomadic groups. Species classified as nomadic showed higher variation in abundance and lower site persistence than species classified as resident. Our method of quantifying nomadism closely replicated existing expert-derived movement classifications of arid zone bird species. Conclusions: Rather than a fixed attribute, movements of many species in our study can be heavily environment-dependent, and individuals of a single species can display a continuum of movements in different times and places. This complicates the conservation of species, but the growing recognition of the complexity of species movements offers opportunities for a more nuanced understanding of the relationship between species and environment. [ABSTRACT FROM AUTHOR]

Large numbers of gamebirds (pheasants Phasianus colchicus, red-legged partridges Alectoris rufa and mallard Anus platyrhynchos) are released annually in the UK to support recreational shooting. It is important to know how many of these birds are being released because their release and management has ecological effects on the wildlife and habitats of the UK. There is little regulation governing their release, and consequently, an accurate figure for the numbers being released is unknown. I took 12 different approaches, totalling 4329 estimates of the numbers of birds being released annually, based on a series of datasets that described numbers of birds being held for breeding, rearing or release, being released, managed or shot on game shoots, being shot by individual guns or being recorded during breeding bird surveys. These 12 approaches produced estimates ranging from 14.7 to 106.1 million with a mean of 43.2 million (95% CI 29.0–57.3 million). This suggests that 31.5 million pheasants (range 29.8–33.7 million), 9.1 million red-legged partridges (range 5.6–12.5 million) and 2.6 million mallard (range 0.9–6.0 million) are released annually in the UK. These figures differ substantially from both official records of gamebirds and previous published estimates, and I discuss why such differences may occur. I set these figures in the context of the number and behaviour of shoots operating in the UK. Improved estimates of numbers of gamebird being released are critical if we are to better understand the ecological effects occurring in areas where they are released and managed. [ABSTRACT FROM AUTHOR]

The use of indicator species can simplify bird monitoring by reducing the level of specialized skills needed, which increases the potential pool of participants and reduces training costs and complexity. To facilitate monitoring in the humid forests of northeast Central America, we conducted point count surveys for birds across gradients of disturbance in the Cockscomb Basin Wildlife Sanctuary, Belize, and analyzed the association of bird species with remotely sensed metrics of forest condition and anthropogenic disturbance using indicator species analysis. Twenty species exhibited significant associations with one or more of these metrics. We propose six species as indicators for anthropogenic disturbance based on our criteria of being associated with anthropogenically disturbed sites, or anthropogenically disturbed and riparian sites with no explicit mention in the literature of an obligate association with riparian habitats, or association of remotely sensed metrics that appeared to reflect disturbance: yellow-olive flycatcher, red-legged honeycreeper, dusky antbird, blue ground dove, buff-throated saltator, and brown jay. We propose the keel-billed motmot as an indicator of undisturbed forest based on its association with forested sites in our analyses. Green shrike vireo, collard trogon, rufous-tailed jacamar, and rufous piha were associated with a specific elevational range but not associated with disturbance, so upward shifts in elevation that might indicate response to climate change would not be confounded with habitat disturbance or degradation. This exercise yielded a much-reduced list of monitoring targets, which will greatly reduce the cost and complexity of forest bird monitoring in the region, as well as reducing barriers to participation. [ABSTRACT FROM AUTHOR]

Background: The analysis of bird community assembly rules is fundamental to understand which mechanisms determine the composition of bird species in urban areas. However, the long-term variation of community assembly rules has not been analyzed yet. The objectives of this study are (1) to analyze the variation of community assembly rules along rural-urban gradients of three cities in central Argentina and (2) to compare the patterns of community assembly between two periods separated by 6 years. Bird surveys were performed along transects in urban, suburban, and rural habitats during 2011 and 2017. Departures from null models that took into account differences in species richness (standardized effect size, SES) were calculated for functional and phylogenetic diversities. Results: A total of 57 species were recorded. Bird species richness was higher in suburban than in urban and rural habitats. SES of functional diversity increased over the years and was significantly lower in urban habitats than in rural habitats, showing a pattern of functional clustering in the most urbanized areas and functional randomness in rural ones. Phylogenetic diversity was higher in both suburban and urban habitats than rural ones, and the phylogenetic clustering in rural bird assemblages changed to randomness in suburban and urban habitats. Conclusions: Bird communities in urban habitats were phylogenetically random and functionally clustered, evidencing environmental filtering by urbanization. In contrast, bird communities in rural areas tended to be phylogenetically clustered, evidencing that certain clades are adapted to rural areas. The processes structuring bird communities along rural-urban gradients were consistent between the 2 years compared. [ABSTRACT FROM AUTHOR]

Background: Habitat degradation is known to have a major impact on the composition of bird communities, yet how these communities recover following such disturbance is less understood. This study examined bird community changes from pre-logging to recovery over the course of habitat disturbance caused by the development of the Hulu Terengganu Hydroelectric Dam Project in Peninsular Malaysia, between 2007 and 2018. Bird surveys were conducted using point count observations and mist netting in the dam area from the pre-logging phase until the operation phase. Results: It was observed that while bird species significantly declined after large-scale habitat clearance between the pre-logging and construction phases, they showed positive signs of recovery from the inundation to operation phases. These findings indicate that the bird community is still recovering, and the permanent loss of habitat required by most of the original species has not occurred, as evidenced by recolonisation. Bird species composition differed across phases due to varying habitat conditions. The turnover rate and immigration rate (recolonisation and newly recorded species) were higher between the construction and operation phases. It was also observed that insectivorous birds were more heavily affected than others by changes to the landscape, which highlights the versatility, survivability and tolerance of certain species to extreme disturbance and habitat modification. Conclusion: Although the operation phase showed an incremental change in bird species richness due to recolonisation and newly recorded species, this value remains far from that of the pre-logging phase. We predict that bird species recovery will continue to increase for some time before reaching a plateau among the newly created islands, reservoir and catchment area of the dam. [ABSTRACT FROM AUTHOR]

The Juruá River is the third largest white-water tributary of the Amazon River, yet, historically, it has not been considered an important barrier for bird communities. The upper region of the Juruá River was the focus of two ornithological collections in the early twentieth century, but the middle region, where the river and surrounding várzea flooded forest widen, has remained largely unexplored by ornithologists. Inspired by Dr. Emilie Snethlage, whose ornithological expeditions to Amazonian rivers during the early twentieth century were foundational in documenting the importance of river barriers, we undertook a month-long expedition to the middle Juruá River. We collected the first modern specimens, high-quality tissues, and sound recordings of birds from the middle Juruá region. Combining our data with those from previous collections, we present the first comprehensive inventory of bird species from the Juruá region, document several significant range extensions, and report the first evidence that the middle Juruá River acts as a barrier in at least four species complexes of terra firme upland forest birds. Our findings have important taxonomic and biogeographic implications for birds of the Juruá region and southwestern Amazon basin. [ABSTRACT FROM AUTHOR]

Automatic bird detection in ornithological analyses is limited by the accuracy of existing models, due to the lack of training data and the difficulties in extracting the fine-grained features required to distinguish bird species. Here we apply the domain randomization strategy to enhance the accuracy of the deep learning models in bird detection. Trained with virtual birds of sufficient variations in different environments, the model tends to focus on the fine-grained features of birds and achieves higher accuracies. Based on the 100 terabytes of 2-month continuous monitoring data of egrets, our results cover the findings using conventional manual observations, e.g., vertical stratification of egrets according to body size, and also open up opportunities of long-term bird surveys requiring intensive monitoring that is impractical using conventional methods, e.g., the weather influences on egrets, and the relationship of the migration schedules between the great egrets and little egrets. [ABSTRACT FROM AUTHOR]

Citizen science monitoring of common birds often involves volunteers visiting selected survey locations twice per year, with interannual differences in the number of birds detected used to infer population trends. Two processes, changes in the timing of migration and breeding in response to climate change, and changes in the timing of surveys by volunteers, may cause variation in the number of birds detected, leading to biases in inferred population trends. We assessed the magnitude of potential biases using the UK Breeding Bird Survey, comparing survey timing, species phenologies and apparent trend biases between 1994–98 and 2013–17. To control for large-scale geographic effects, we focussed on a subset of 888 surveyed 1 km squares in South-East England. Survey dates became significantly earlier, advancing by 2–4 days on average. We calculated seasonal patterns of bird abundance for 68 species. After standardising these to remove long-term abundance trends, median detection dates were advanced by 0.82 days on average. At the species level, the majority of changes were ± 2 days and only five species showed a significant advancement in median detection date. However, species' phenological changes alone are capable of inducing between an 8% suppression and 21% enhancement of species' trends, although the majority are ± 2%. Effects of a similar magnitude are apparent if survey timings are also allowed to change, although different species are affected. Small modifications to the statistical model used to generate trends can control for changes in survey timing, but without additional survey visits, or using data from other sources, we cannot currently control for seasonal variation in detectability. Although the average effects shown here are small, biases could become increasingly important for some species, and we recommend organisers of biodiversity monitoring schemes assess whether their methods are resistant to variations in species phenology and survey timing. [ABSTRACT FROM AUTHOR]

Context: Biodiversity in tropical region has declined in the last decades, mainly due to forest conversion into agricultural areas. Consequently, species occupancy in these landscapes is strongly governed by environmental changes acting at multiple spatial scales. Objectives: We investigated which environmental predictors best determines the occupancy probability of 68 bird species exhibiting different ecological traits in forest patches. Methods.: We conducted point-count bird surveys in 40 forest sites of the Brazilian Atlantic forest. Using six variables related to landscape composition and configuration and local vegetation structure, we predicted the occupancy probability of each species accounting for imperfect detections. Results: Landscape composition, especially forest cover, best predicted bird occupancy probability. Specifically, most bird species showed greater occupancy probability in sites inserted in more forested landscapes, while some species presented higher occurrence in patches surrounded by low-quality matrices. Conversely, only three species showed greater occupancy in landscapes with higher number of patches and dominated by forest edges. Also, several species exhibited greater occupancy in sites harbouring either larger trees or lower number of understory plants. Of uttermost importance, our study revealed that a minimum of 54% of forest cover is required to ensure high (> 60%) occupancy probability of forest species. Conclusions: We highlighted that maintaining only 20% of native vegetation in private property according to Brazilian environmental law is insufficient to guarantee a greater occupancy for most bird species. We recommend that policy actions should safeguard existing forest remnants, expand restoration projects, and curb human-induced disturbances to minimise degradation within forest patches. [ABSTRACT FROM AUTHOR]

In Indonesia, the songbird trade is causing serious declines in many native species. Much of this trade is unregulated or illegal but nevertheless occurs openly in physical wildlife markets and online. Here, we report on the trade in a once common songbird, the Sunda laughingthrush (Garrulax palliatus), using compiled market data from 365 bird market surveys across a 30-year period. We found a total of 5,281 birds for sale, with the species encountered in roughly two-thirds of the visits. We observed a significant decrease in the number of Sunda laughingthrushes offered over time from ~ 50 birds/survey in the 1990s to ~ 20 birds/survey in the 2000s and < 10 birds/survey in the 2010s, as well as a significant increase in the market price of the species, suggesting declining populations. In line with the countrywide findings, we found a decrease in the number of the species in the bird markets of Medan, but we did not find a similar decrease in Jakarta, suggesting a complex pattern of availability and demand. Nevertheless, this study shows that continued trapping for trade, if left unchecked, poses a significant risk to the species. We conclude that a more proactive stance from the government, including increasing levels of protection and enforcement of existing regulations, community engagement and possibly targeted captive breeding may alleviate the pressure on remaining wild populations. Our study offers a model whereby analysis of wildlife trade over extended periods of time covering vast geographic regions may offer insights that are easily missed when working in a too focused manner on single markets over short periods of time. [ABSTRACT FROM AUTHOR]

Context: There is an ongoing debate whether local biodiversity is declining and what might drive this change. Changes in land use and land cover (LULC) are suspected to impact local biodiversity. However, there is little evidence for LULC changes beyond the local scale to affect biodiversity across multiple functional groups of species, thus limiting our understanding of the causes of biodiversity change. Objectives: Here we investigate whether landscape-wide changes in LULC, defined as either trends in or abrupt changes in magnitude of photosynthetic activity, are driving bird diversity change. Methods: Linking 34 year (1984–2017) time series at 2745 breeding bird survey (BBS) routes across the conterminous United States of America with remotely-sensed Landsat imagery, we assessed for each year what proportion of the landscape surrounding each BBS route changed in photosynthetic activity and tested whether such concomitant or preceding landscape-wide changes explained changes in bird diversity, quantified as relative abundance (geometric mean) and assemblage composition (Bray–Curtis index). Results: We found that changes in relative abundance was negatively, and assemblage composition positively, correlated with changes in photosynthetic activity within the wider landscape. Furthermore, landscape-wide changes in LULC in preceding years explained on average more variation in bird diversity change than concomitant change. Overall, landscape-wide changes in LULC failed to explain most of the variation in bird diversity change for most BBS routes regardless whether differentiated by functional groups or ecoregions. Conclusions: Our analyses highlight the influence of preceding and concomitant landscape-wide changes in LULC on biodiversity. [ABSTRACT FROM AUTHOR]

Ticks are ectoparasites that feed on blood of a broad taxonomic range of terrestrial and flying vertebrates and are distributed across a wide range of environmental conditions. Here, we explore the biotic and abiotic factors on infestation probability of ticks of the genus Amblyomma and assess the degree of host specificity based on analysis of 1028 birds surveyed across Brazil. We show that tick infestation rates exhibited considerable variation across the 235 avian species analyzed and that the probability of an individual bird being parasitized by immature ticks (larvae and nymphs) increased with annual precipitation. Host phylogeny and two host ecological traits known to promote tick exposure (body mass and foraging behavior) did not predict infestation probability. Moreover, immature ticks displayed a low degree of host specificity at the family level. Lastly, tick occurrence in birds carrying infection with avian malaria and related parasites did not differ from those free of these haemosporidian parasites, indicating a lack of parasite avoidance by immature ticks. Our findings demonstrate that tick occurrence in birds across Brazilian biomes responds to environmental factors rather than ecological and evolutionary host attributes. [ABSTRACT FROM AUTHOR]

Context: Since 2005, unconventional gas development has rapidly altered forests across the Marcellus-Utica shale basin in the central Appalachian region of the eastern United States, an area of high conservation value for biodiversity. Much is still unknown about ecological impacts of associated land cover change. Objectives: Our goal was to identify threshold responses among bird species and habitat guilds to (1) overall forest loss and fragmentation in affected landscapes, and (2) distance from anthropogenic disturbance, both related and unrelated to shale gas. Methods: We conducted 2589 bird surveys at 190 sites across this region, and quantified community-level and species-specific thresholds relating to forest cover and distance to anthropogenic disturbance, using Threshold Indicator Taxa Analysis (TITAN). Results: Forest interior species decreased abruptly in abundance and frequency of occurrence above a threshold of 17.0% overall forest loss, while early successional and synanthropic species increased abruptly above 30.5–36.5% forest loss, respectively. Broad quantile intervals around responses to distance from anthropogenic disturbance suggest these were not sharp threshold responses, but more gradual or linear responses. Among forest interior species evaluated, 48.1% increased in abundance farther from shale gas development, while 55.6% of early successional and synanthropic species decreased. Conclusions: We found evidence of avian threshold responses to overall forest loss and fragmentation in affected landscapes across the Marcellus-Utica shale region. Our results suggest that efforts to avoid shale gas development in regional core forests—particularly those still retaining ≥ 83% forest cover—can reduce negative effects on area-sensitive, forest interior dependent species. [ABSTRACT FROM AUTHOR]

Window strikes are among the most worrisome causes of bird mortality. Being responsible for billions of avian deaths, bird-window collisions have been widely studied in the US and Canada, with few studies from Europe, Asia, and Latin America. Thus, there is still a dearth of knowledge regarding this alarming phenomenon in regions where biodiversity and urbanization peek, such as Latin America. In this study, we assessed bird-window collisions in Xalapa, a small-to-medium-sized Neotropical city located in Southeast Mexico. We gathered data under two schemes: (1) a standardized survey procedure and (2) non-systematic records. Regarding the former, we evaluated the role of building and surrounding vegetation traits, as well as the location of focal buildings in driving bird-window collisions. Considering both schemes, we recorded bird-window collisions for 43 species. The most frequent striking groups were hummingbirds and thrushes, which had already been identified as vulnerable given some of their natural and life history traits. Regarding the standardized survey, we found no statistical differences in the number of collisions among seasons; yet, we did record a predominance of strikes from resident bird species over migrants among all studied seasons. Our results show a significant positive relationship between the amount of surrounding vegetation area of the studied buildings and bird-window collision frequency, while building non-glass material area showed a significant negative relationship. Based on our findings and the limitations of our study, we encourage future research to combine systematic and standard surveys throughout the year with citizen science, together with carcass removal assessments and bird density surveys in the immediate vicinity of focal buildings. [ABSTRACT FROM AUTHOR]

The increasing demand for robust marine bird abundance and distribution assessments coupled with technological advances has led to the development of digital survey techniques for birds. Although digital surveys for bird monitoring are becoming a standard method in some countries, their strengths and weaknesses and comparability with traditional visual surveys remain insufficiently documented and understood. Aiming to improve existing knowledge on digital video monitoring techniques, we conducted one parallel digital video survey with 2-cm ground resolution and a 544-m swath flown at 549 m and an aerial visual survey flown at 76 m over the southern Baltic Sea in March 2015. We assessed bird sighting rates, identification rates, observed densities, and model-based abundance estimates. The digital survey covered a larger area through direct registrations, provided higher numbers of bird sightings and identified species, and higher spatial accuracy than the visual survey. Overall species identification rates were similar between the survey methods; however, there were marked differences among bird taxonomic groups: more individuals were identified to species level in the digital survey dataset for the majority of taxonomic groups, except for grebes and auks. These advantages supplement other previously identified benefits of digital aerial surveys, such as the elimination of bird disturbance due to high flight altitude, reduced observer bias, and availability of raw data for quality assurance. Furthermore, higher numbers of direct bird sightings at a higher spatial resolution during digital surveys ensure better statistical analyses, including distribution modelling, of more species for the same survey effort. [ABSTRACT FROM AUTHOR]

Power-line grids are increasingly expanding worldwide, as well as their negative impacts on avifauna, namely the direct mortality through collision and electrocution, the reduction of breeding performance, and the barrier effect. On the other hand, some bird species can apparently benefit from the presence of power lines, for example perching for hunting purposes or nesting on electricity towers. In this perspective essay, we reviewed the scientific literature on both costs and benefits for avifauna coexisting with power lines. Overall, we detected a generalized lack of studies focusing on these costs or benefits at a population level. We suggest that a switch in research approach to a larger spatio-temporal scale would greatly improve our knowledge about the actual effects of power lines on bird populations. This research approach would facilitate suitable landscape planning encompassing both mitigation of costs and promotion of benefits for bird populations coexisting with power lines. For example, the strategic route planning of electricity infrastructures would limit collision risk or barrier effects for threatened bird populations. Concurrently, this strategic route planning would promote the range expansion of threatened populations of other bird species, by providing nesting structures in treeless but potentially suitable landscapes. We suggest establishing a collaborative dialogue among the scientific community, governments, and electricity companies, with the aim to produce a win-win scenario in which both biodiversity conservation and infrastructure development are integrated in a common strategy. [ABSTRACT FROM AUTHOR]

Context: Complex structural connectivity patterns can influence the distribution of animals in coastal landscapes, particularly those with relatively large home ranges, such as birds. To understand the nuanced nature of coastal forest avifauna, where there may be considerable overlap in assemblages of adjacent forest types, the concerted influence of regional landscape context and vegetative structural connectivity at multiple spatial scales warrants investigation. Objectives: This study determined whether species compositions of coastal forest bird assemblages differ with regional landscape context or with forest type, and if this is influenced by structural connectivity patterns measured at multiple spatial scales. Methods: Three replicate bird surveys were conducted in four coastal forest types at ten survey locations across two regional landscape contexts in northeast Australia. Structural connectivity patterns of 11 vegetation types were quantified at 3, 6, and 12 km spatial scales surrounding each survey location, and differences in bird species composition were evaluated using multivariate ordination analysis. Results: Bird assemblages differed between regional landscape contexts and most coastal forest types, although Melaleuca woodland bird assemblages were similar to those of eucalypt woodlands and rainforests. Structural connectivity was primarily correlated with differences in bird species composition between regional landscape contexts, and correlation depended on vegetation type and spatial scale. Conclusions: Spatial scale, landscape context, and structural connectivity have a combined influence on bird species composition. This suggests that effective management of coastal landscapes requires a holistic strategy that considers the size, shape, and configuration of all vegetative components at multiple spatial scales. [ABSTRACT FROM AUTHOR]

Quantifying species turnover is an important aspect of biodiversity monitoring. Turnover measures are usually based on species presence/absence data, reflecting the rate at which species are replaced. However, measures that reflect the rate at which individuals of a species are replaced by individuals of another species are far more sensitive to change. In this paper, we propose families of turnover measures that reflect changes in species proportions. We study the properties of our measures, and use simulation to assess their success in detecting turnover. Using data on the British farmland bird community from the breeding bird survey, we evaluate our measures to quantify temporal turnover and how it varies across the British mainland. [ABSTRACT FROM AUTHOR]

Urbanization has been considered as a major threat to biodiversity, making its ecology of increasing interest. Many urban ecology studies have been developed in a short time-scale, measuring real-time patterns. However, long-term studies are imperative to understand the responses of some species to the urbanization process. In this study, we aimed to assess the information provided by a recent one-year citywide bird survey when compared to a published 'historical' bird list of a neotropical city (Xalapa, Mexico) that compiles information of the past three decades, mainly from urban greenspaces. Specifically, we contrasted species richness values and assessed differences in species composition between both lists. We recorded 51 species in the one-year citywide survey, representing ~15 % of those reported in the historical list. Nonetheless, the upper-bound confidence interval of the citywide survey richness prediction represented ~66 %. Most of the species recorded in the one-year citywide survey are insectivores and granivores, a pattern that agrees with previous findings that underline the importance of insectivores as part of urban bird communities in the Neotropics. Although we used robust methods to compare our one-year citywide bird list and the historical list for the city of Xalapa, we acknowledge the limitations of comparing them. However, our results shed some light on the kind and type of information that one-year citywide surveys can provide and the importance of long-term studies for comprehending the processes involved in biodiversity changes within urban areas over time. Undoubtedly, establishing long-term citywide surveys sampling birds and other biodiversity groups will allow us to better understand the response of biodiversity to urbanization over time. [ABSTRACT FROM AUTHOR]

In some Australian and South American cities, nectarivorous birds have become a conspicuous component of the avifaunal community. One mechanism that has been proposed to explain their success is an increased availability of nectar that is provided by suburban gardens and other ornamental plantings. To determine whether the amount of nectar within the suburban landscape is comparable to that of the natural environment, we measured floral density and nectar concentrations in 24 sites in Sydney, Australia. We also measured the density of four species of nectarivores and available nectar energy over a period of 18 months within the suburban landscape (streetscapes and remnant vegetation) and the natural environment (forest and heathland) to determine whether nectar availability explains nectarivore density. Two species of nectarivorous parrot, the rainbow lorikeet and musk lorikeet were present in higher densities within the suburban landscapes compared to the natural environment, and the suburban landscapes provided significantly more nectar than the natural environment during spring and winter. Both the rainbow lorikeet and musk lorikeet were associated with flowering of Eucalyptus spp. and red wattlebirds with the flowering of Grevillea and Callistemon spp. within streetscapes. Suburban landscapes appear to provide a constant supply of nectar for large-bodied nectarivores and provide for more efficient foraging, explaining the success of these species in urban environments. [ABSTRACT FROM AUTHOR]

We developed an innovative method for finding individuals of a conspicuous species in complex urban habitats. The aim of this study was to detect as many burrowing owl nests as possible in order to develop an ecological and behavioral study. We performed an online survey through the social network, Facebook. The results of this survey allowed us to detect and locate 36 new burrowing owl nests. We conclude that developing online surveys through social networks is an innovative and cost-effective method to obtain information about bird locations, and can complement traditional methods such as field surveys. [ABSTRACT FROM AUTHOR]

Early warning systems of extinction thresholds have been developed for and tested in microcosm experiments, but have not been applied to populations of wild animals. We used state-space population models and a statistical indicator to detect a transcritical bifurcation extinction threshold in a population of bobwhite quail ( Colinus virginianus) located in an agricultural region experiencing habitat deterioration and loss. The extinction threshold was detectible using two independent data sets. We compared predictions from state-space population models to predictions from a statistical indicator and found that predictions were corroborated. Using state-space population models, we estimated that our study population crossed the extinction threshold in 2010 (2002-2036; 95 % confidence intervals [CI]) using the whistle count (WC) data set and in 2008 (1999-2064; 95 % CI) using the Breeding Bird Survey (BBS) data. With the statistical indicator, we estimated that the extinction threshold will be crossed in 2018 (2004-2031; 95 % CI) using the WC data and will be crossed in 2012 (2006-2018; 95 % CI) using the BBS data. We expect extinction in our study population soon after crossing the extinction threshold, but the time to extinction and potential reversibility of the threshold are unknown. Our results suggest that neither small nor decreasing population size will warn of the transcritical bifurcation extinction threshold. We suggest that managers of wildlife populations in regions experiencing land use change should try to predict extinction thresholds and make management decisions to ensure the persistence of the species. [ABSTRACT FROM AUTHOR]

Remote sensing is a valuable tool for wetland habitat quantification, monitoring and assessment. Here we show that habitat assessment via aerial image inspection is useful in predicting wetland site occupancy by black terns ( Chlidonias niger), an imperiled and declining species throughout much of North America. We used Google Earth images and National Wetlands Inventory maps to rank 390 candidate wetlands throughout Wisconsin (USA) according to their apparent suitability as nesting habitat for black terns and quantified habitat features associated with the suitability rankings. We then conducted ground-based suitability assessments and point counts of terns at most wetlands from May to July 2010. Pre-survey assessment resulted in 123 wetlands classified as suitable, 81 as marginal, and 186 as unsuitable. Wetlands ranked as suitable were more likely to be in the hemi-marsh stage, part of a wetland complex and relatively undisturbed. Black terns were present at 47 % of the wetlands considered suitable but only 11 % of the sites considered marginal or unsuitable. Of the 42 sites where nesting was confirmed, 79 % were at wetlands classified as suitable; no nesting was recorded in any wetlands deemed unsuitable. We found strong concordance in wetland suitability rankings between the two assessment methods (remote sensing, site surveys). We propose that remote sensing is an efficient and inexpensive way to predict site occupancy by wetland birds, such as black terns, that prefer a specific kind of habitat discernible from aerial imagery. This method may be particularly useful in areas, such as the Prairie Pothole region of North America, where ground surveys of all wetlands are not feasible. [ABSTRACT FROM AUTHOR]

The results of bird route surveys over the territory of the Central Altai during the summer seasons in 1968-2001 were analyzed. Hierarchic classifications of species by the similarities of residence and distribution were compiled on the basis of a multivariate factor analysis. The basic environmental factors that determine the non-uniformity of bird distribution were revealed. It was demonstrated that the classifications of bird species in the central Altai province and in the Altai physiogeographic mountainous region are, in general, similar in structure. The provincial specificity of distribution intensifies with an increase in the altitude of the territory. [ABSTRACT FROM AUTHOR]

When estimating the size of seabird populations, count data may be biased due to various factors such as detection probability. Failing to account for detection probability in surveys may lead to an underestimate of population size and may compromise the ability to monitor trends if detection probability varies among surveys. Here, we use the double-observer method to estimate detection probability of cavity-nesting snow petrels ( Pagodroma nivea) and Wilson's storm petrels ( Oceanites oceanicus) in East Antarctica. Estimates of single-visit detection probability of nesting/roosting adult snow petrels during the incubation stage of the breeding cycle ranged from 0.86 (SE = 0.04) to 0.87 (SE = 0.04) depending upon observers. Both observers found snow petrel chicks were easier to detect than adults, with estimated detection probability for chicks ranging from 0.92 (SE = 0.03) to 1.00 (SE = 0.34 × 10). Detection probability of adult and chick snow petrels increased as cavity volume increased. Compared to snow petrels, estimated detection probability was considerably lower for nesting/roosting Wilson's storm petrels, ranging from 0.27 (SE = 0.09) to 0.50 (SE = 0.13) for each observer. These estimates of detection probability apply only to those individuals in the population that were potentially viewable or audible. Nevertheless, our results indicate that double-observer counts for ground surveys of cavity-nesting seabirds should improve estimates of population abundance in comparison with single-visit counts. Accounting for observer effects, habitat characteristics and stage of the breeding season on detection probability should also improve estimation of population trends. [ABSTRACT FROM AUTHOR]

Birds are important components of biodiversity conservation since they are capable of indicating changes in the general status of wildlife and of the countryside. The Pan-European Common Bird Monitoring Scheme (PECBM) has been launched by the BirdLife Partnership in Europe, where the European Bird Census Council has been collecting data from 20 independent breeding bird survey programs across Europe over the last 25 years. These data show dramatic declines in European farmland birds. We suggest that seasonal characteristics of vegetation cover derived from high temporal resolution remote sensing images could facilitate the monitoring the suitability of farmland bird habitats, and that these indicators may be a better choice for monitoring than climate data. We used redundancy analysis to link the PECBM data of the estimated number of farmland birds in Europe to a set of phenological and climatic indicators and to the biogeographic regions of Europe. Variance partitioning was used to account for the variation explained by the phenological and climate variables and by the area of the environmental strata individually, to define the pure effect of the variables, and to extract the total explained variance. The analysis revealed high statistical significance ( p < 0.001) of the correlations between species and environment. Phenological indices explained 38% of the variance in community composition of the 23 farmland bird species, whereas climate explained 30% of the variance. After partitioning the other variables as covariables, the pure effect of phenology, climate, and environmental strata were 16%, 8%, and 16%, respectively. Based on the probability results, we suggest that phenological indicators derived from remote sensing may supply better indicators for continental scale biodiversity studies than climate only. In addition, these indicators are cost and time effective, are on continuous scale, and are readily repeatable on a large spatial coverage while supplying standardized results. [ABSTRACT FROM AUTHOR]

Distance sampling (DS) and territory mapping (TM) are globally applied bird survey techniques. However, specifically designed studies comparing results of both methods in different habitats in the framework of a scientific experiment have rarely been conducted. To provide a more generalized guidance for the field surveyor, here we evaluated estimates of bird abundances and number of bird species in four different habitats (broad-leaved forest, coniferous forest, open woodland and farmland) in central Germany. Abundances were estimated in parallel by TM and DS in 2006 and 2008, following standard protocols. Detection probability differed significantly among habitats and species. Density estimates by DS were in total 24% lower than those estimated by standardized TM. While the number of bird species detected with both methods was approximately the same, the estimated abundances of 15 bird species showed significant differences. Increasing the number from two to four and five registrations to count a territory by using TM decreased the density on average about 28 and 42%, respectively. Using standardized TM resulted in an overestimation of abundances of species showing a high detection probability. In contrast, DS estimated very high densities for species that had a very low detection probability. In fact, a highly negative correlation was found between the density estimated by DS and the detection probability. Using standardized TM and setting a fixed number of registrations before a location qualifies for a bird territory cannot compensate for the large differences in species detectability. Instead, the number of registrations required to count a territory should be adjusted to differences in detection probabilities and seasonal activity. From our results we can recommend a mean of four registrations if eight visits were conducted to count a territory. However, the lack of any statistically-based quality assessment reduces the serious usability of TM for estimating densities for science-based management application, whereas, the clear advantage of DS is that it provides error estimates and considers differences in species detectability. [ABSTRACT FROM AUTHOR]

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Despite the increasing claims that structural complexity in agroforestry plantations is a key variable for enhancing bird biodiversity, few studies have experimentally manipulated the understory component of structural complexity. Here, we examined the impact of removing understory vegetation from oil palm plantations on the richness and abundance of birds in eastern Guatemala, testing if bird richness and abundance are positively affected by the presence of understory vegetation. Oil palm plantations with understory hold more bird richness and abundance than those lacking it. The experimental removal of this vegetation, equivalent to a reduction in complexity, decreases bird richness but not abudance. Our analysis shows clear effects of vegetation removal on bird richness, such that removal reduces richness and abundance to levels found in areas without understory. Hence, leaving or implementing structural complexity within plantations could satisfy the current need of making commodity production a cleaner industry, fulfilling both, the production of highly demanded commodities and the conservation of biodiversity in productive landscapes. Oil palm ( Elaeis guineensis) is one of the most rapidly expanding crop in tropical regions, representing the major cause of loss of natural forests and of the decline of endangered species in several countries. Enhancing understory vegetation might reduce such negative effects. This is one of the few experimental tests about how a component of the vegetation and structural complexity of plantations affects birds. [ABSTRACT FROM AUTHOR]

Recently, there have been several reports from different parts of the World on the declining populations of the House Sparrow (Passer domesticus). In order to assess the population of this species in the National Capital Territory of Delhi-India, this study was conducted during June- August in 2007. Twenty-eight Fixed-Radius Point Count stations were established in five habitat types viz. High-density Urban Area, Mediumdensity Urban Area, Low-density Urban Area, Agriculture Area, and Forested Area, within the study area. The results show that the House Sparrow is still a dominant species in the agriculture area. However, its density is very low in the urban areas as compared to the other co-occurring common bird species viz. Rock Pigeon (Columba livia domestica), House Crow (Corvus splendens) and Common Myna (Acridotheres tristis). As, this study was conducted only over one season, the data is not sufficient to provide a clear picture of the population trend of the House Sparrow. Further studies are therefore required to investigate the relationship of the House Sparrow with other co-occurring common species, and to analyse the data on the type and quality of greenspaces and their relation with the House Sparrow in the study area. A long-term monitoring and conservation programme involving local people may be a good approach for maintaining the population of House Sparrow in the study area. [ABSTRACT FROM AUTHOR]

Mediterranean landscapes resulted from complex land uses that produced a mosaic of extensive crops, grasslands, scrublands and scattered woodlands. During the twentieth century the decrease in traditional agriculture triggered a decrease in open habitats and an increase in forests. In the meantime urban centres grew dramatically. Both spread of forest and urban areas have been suspected to participate in the decline of typical Mediterranean bird species and, in general, to cause faunal loss. However, modern cities offer a variety of landscape types and, in the Mediterranean, their value for native bird species has been little assessed. We compared the bird communities from an urban landscape, including built up and natural or semi natural units within the limits of the city of Montpellier, to the bird communities from non-urban habitats (cropland, grassland and woodland) located nearby but away from direct urban influence. Fifty four percent of the bird species recorded in the non-urban habitats also occurred in the urban landscape. On average, estimated species richness in the urban landscape was similar to values obtained for non-urban habitats. Within the urban landscape species richness was lowest in the dense historical centre and highest in the residential areas. The residential areas and urban woods were suitable habitats for most generalist species but also for several more specialized species recorded in the non-urban habitats. Some species actually reached their highest observation frequency in the urban landscape. Urban landscape was least favourable to the same farmland and open-habitat specialists that have been negatively affected by agricultural abandonment in the region. Finally, five of the species common in the urban landscape had an unfavorable conservation status in 2004 in the EU. This study emphasizes that Mediterranean urban areas have the potential to host a diverse native bird community. Finding ways to improve their carrying capacity for the local avifauna might be a worthwhile objective for animal conservation. [ABSTRACT FROM AUTHOR]

This study examined native bird communities in forest patches across a gradient of urbanization. We used field data and multivariate statistical techniques to examine the effects of landscape context, roads, traffic noise, and vegetation characteristics on bird community composition in the North Carolina Piedmont (U.S.A.). Landscape-level variables, particularly those related to urbanization, were most important in structuring forest bird communities. Specifically, we found that road density and amount of urban land cover were the best predictors of species composition. We found that urban and rural bird communities were quite distinct from each other. Rural communities had more long-distance migrants and forest interior species but species richness did not differ between the communities. Our results suggest some specific guidelines to target bird species of interest both inside and outside of urban areas. For example, if increasing numbers of migratory species is of primary concern, then conservation areas should be located outside of urban boundaries or in areas with low road density. However, if maximizing species richness is the focus, location of the conservation area may not be as important if the conservation area is surrounded by at least 50 m of forest habitat in all directions. [ABSTRACT FROM AUTHOR]

In this study we developed a simple quantitative method to assist in the decision making process of the landscape planning by integrating information of species occurrence and their individual IUCN extinction risks. We applied this method in Catalonia (north-east Iberian Peninsula) using bird atlas data to create an Index of Cumulative Threat Status (ICUTS). We employed a heuristic approach derived from qualitative scores provided by 10 experts on the avifauna of the region to choose the final index among a group of candidates. This index was used to generate two maps of conservation value at 10 x 10 km resolution, one comprising all breeding bird species in the study region (219 species), and a second one with only those bird species for which fine-grained maps (500 x 500 m) were also available (182 species). In spite of the difference in the number of species included in the two 10 x 10 km maps, we found similar geographical patterns and therefore we considered that the pattern shown by the second group of species (at 500 x 500 m resolution) represented a good proxy of the whole breeding avifauna for landscape planning purposes. The approach developed in this study may be particularly helpful in landscape planning outside protected areas because of its spatial continuity, finegrained resolution and easy interpretation. [ABSTRACT FROM AUTHOR]

Mesoamerican cloud forests are important centres of biodiversity, but are under severe pressure from anthropogenic activities. Protected areas have been established to conserve remaining areas of this habitat, but it is debatable how effective these underresourced 'paper parks' are in preserving biodiversity. This study investigates this issue utilising species-level data, examining composition of avifaunal communities within an undermanaged cloud forest park. Research was conducted in the Parque Nacional Cusuco, North-West Honduras. Results indicate that overall avian species richness is greater in the less heavily protected buffer zone than the nominally inviolate core zone. However, core zone areas are shown to be effective in preserving threatened and range-restricted species. Results therefore demonstrate that buffer zone forest has a comparably reduced conservation value, but the overall park system appears to be effective in conserving the core zone. These findings should be taken into account when considering extensions to protected area networks in Mesoamerica. [ABSTRACT FROM AUTHOR]