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Comprehensive characterization of structural variation in natural populations has only become feasible in the last decade. To investigate the population genomic nature of structural variation, reproducible and high-confidence structural variation callsets are first required. We created a population-scale reference of the genome-wide landscape of structural variation across 33 Nordic house sparrows (Passer domesticus). To produce a consensus callset across all samples using short-read data, we compare heuristic-based quality filtering and visual curation (Samplot/PlotCritic and Samplot-ML) approaches. We demonstrate that curation of structural variants is important for reducing putative false positives and that the time invested in this step outweighs the potential costs of analyzing short-read–discovered structural variation data sets that include many potential false positives. We find that even a lenient manual curation strategy (e.g. applied by a single curator) can reduce the proportion of putative false positives by up to 80%, thus enriching the proportion of high-confidence variants. Crucially, in applying a lenient manual curation strategy with a single curator, nearly all (>99%) variants rejected as putative false positives were also classified as such by a more stringent curation strategy using three additional curators. Furthermore, variants rejected by manual curation failed to reflect the expected population structure from SNPs, whereas variants passing curation did. Combining heuristic-based quality filtering with rapid manual curation of structural variants in short-read data can therefore become a time- and cost-effective first step for functional and population genomic studies requiring high-confidence structural variation callsets. [ABSTRACT FROM AUTHOR]

Simple Summary: Urban areas are constantly increasing, as well as human activities related to them. This can lead to an effect in bird populations due to the alterations caused in nature. According to the latest national censuses in Spain, House Sparrow and Eurasian Tree Sparrow populations are decreasing. In this study, we used ringing station data from Spain to assess the tendency of both populations over a two-decade period of time. We also tried to determine the relation of these two populations and their breeding success with the habitat composition. The data analysis confirmed the decreasing trend in both species. However, Eurasian Tree Sparrow showed signs of increasing presence in urban areas, contrary to our predictions. Furthermore, the productivity of both populations remained stable over the study years. Urban areas are constantly increasing, which can cause an effect in bird populations since human activities lead to nature alterations. Populations of House Sparrow (Passer domesticus) and Eurasian Tree Sparrow (Passer montanus) have been decreasing in Spain according to the latest national censuses in Spain. In this study, we tried to assess the population trend over more than two decades using ringing data from Spanish constant effort sites, as well as to determine the population and breeding success proxy in relation to habitat composition at landscape level. We analysed the data and confirmed the decreasing trend in the two species. However, Eurasian Tree Sparrow showed signs of increasing presence in urban areas. Furthermore, the productivity remained stable over sampling sites and years, meaning that the causes of the decreasing populations are affecting both adult and juvenile individuals. [ABSTRACT FROM AUTHOR]

Aim: The increasing spread of vector‐borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations. Location: Global. Time period: 2002–2019. Major taxa studied: Avian Plasmodium parasites in house sparrows. Methods: We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests. Results: Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected. Main conclusions: Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows. [ABSTRACT FROM AUTHOR]

Invasive birds cause damage to economies, natural resources, and human safety across the globe. In the United States, rock doves (Columba livia), Eurasian collared doves (Streptopelia decaocto), rose-ringed parakeets (Psittacula krameri), monk parakeets (Myiopsitta monachus), common mynas (Acridotheres tristis), European starlings (Sturnus vulgaris), and house sparrows (Passer domesticus) are among the invasive and often harmful small-bodied birds inhabiting periurban habitats. The destructive nature of these species warrants a review of methods to reduce or eradicate populations along with methods to reduce damage when population eradication cannot be achieved. We reviewed damage management literature from these species' native and introduced ranges. Additionally, we used the behavior and ecology of these species to inform tool recommendations and potential efficacy under various damage scenarios, while being sensitive to cultural preferences and location of implementation (residential, commercial, and agricultural). Although this review focuses on invasive birds in the United States, it is applicable to other pest species across the globe. Our review highlights areas where research is needed to validate promising damage management methods (lethal control, fertility control, habitat modification, exclusionary methods, frightening devices, and chemical repellents). Where birds are invasive, integrated pest management techniques should focus on eradication or population reduction (toxicants, shooting, and trapping) to keep populations at levels where nonlethal tools can reduce damage. We acknowledge the efficacy of an eradication campaign depends on biological, environmental, and economic factors, along with social license for lethal removal. We recommend integrated pest management strategies including lethal and nonlethal tools specific to the damage problem. Sustained efforts to reduce invasive populations should be used along with integrated deterrent strategies for short-term damage relief. [ABSTRACT FROM AUTHOR]

Humans' large influence on the environment has constructed many new ecological niches, such as in urban areas. Phenotypic changes, including morphological ones related to human influence, are known from a small number of bird species. The amount of change in a given time period, that is, the rate of change, may vary. Rates of change (both evolutionary and through phenotypic plasticity) are reportedly rapid in human‐influenced settings, although this is disputed. We present new data on changes in beak dimensions and rates of change over historical time periods in four urban bird species (Common Chaffinch, European Greenfinch, Eurasian Blackbird, House Sparrow) from three Swiss cities (Basel, Bern, Geneva). Our study shows that beak dimensions have changed little in most investigated urban bird populations over the past century. Only in Genevan Blackbirds there was evidence for an increase in beak length over the past 65 years; Bernese Chaffinches appear to be trending toward a decrease in beak width over the past 55 years. Rates of change in our sample in comparison with literature records showed that compared to populations less influenced by humans, urban evolutionary rates appear to be similar. Although in accordance with previous findings about other urban bird species, our study exemplifies the difficulty to find universal patterns in tempo and mode of phenotypic evolution in urban areas, even when considering the same taxa. Our data contribute to the expanding field of urban evolutionary biology, which is particularly important regarding the growing urban habitats worldwide. [ABSTRACT FROM AUTHOR]

Anthropogenic pollution is identified as an important threat to bird and other wildlife populations. Many metals and toxic elements, along with poly- and perfluoroalkyl substances (PFASs) are known to induce immunomodulation and have previously been linked to increased pathogen prevalence and infectious disease severity. In this study, the house sparrow (Passer domesticus) was investigated at the coast of Helgeland in northern Norway. This population is commonly infected with the parasitic nematode "gapeworm" (Syngamus trachea), with a prevalence of 40–60 % during summer months. Gapeworm induces severe respiratory disease in birds and has been previously demonstrated to decrease survival and reproductive success in wild house sparrows. The aim of this study was to investigate whether a higher exposure to pollution with PFASs, metals and other elements influences gapeworm infection in wild house sparrows. We conducted PFASs and elemental analysis on whole blood from 52 house sparrows from Helgeland, including analyses of highly toxic metals such as lead (Pb), mercury (Hg) and arsenic (As). In addition, we studied gapeworm infection load by counting the parasite eggs in faeces from each individual. We also studied the expression of microRNA 155 (miR155) as a key regulator in the immune system. Elevated blood concentrations of Pb were found to be associated with an increased prevalence of gapeworm infection in the house sparrow. The expression of miR155 in the plasma of the house sparrow was only weakly associated with Pb. In contrast, we found relatively low PFASs concentrations in the house sparrow blood (∑ PFASs 0.00048–354 μg/L) and PFASs were not associated to miR155 nor infection rate. The current study highlights the potential threat posed by Pb as an immunotoxic pollutant in small songbirds. [Display omitted] • Helgeland, northern Norway, local bird populations are contaminated by toxic elements. • Elevated Pb levels modulate the expression of miR155. • Elevated blood concentrations of Pb are linked to a higher prevalence of gapeworm infection. [ABSTRACT FROM AUTHOR]

Mycoses of wild birds are rarely addressed in scientific research. We tested the hypothesis that urban populations of House Sparrow Passer domesticus, which in many cities showed downward trends in their number and are characterized by lower body mass and poorer body condition, would be more frequently colonized by fungi. To evaluate the degree of bird colonization by fungi, swabs were taken from the beak cavity and cloaca of birds from urban and rural populations in the breeding season. A high degree of bird colonization by fungi was determined in both types of habitats (urban: 86% of population; rural: 92% of population). In total, 26 species of fungi were isolated (urban: 15 species; rural: 22 species). No significant differences were determined between the number of fungi species identified in birds from urban and rural habitats and between the degree of colonization of the two ontocenoses (beak cavity and cloaca). In both environments, Candida krusei turned out to be the prevalent fungus, with a clear predominance in the urban population. The extent of ontocenoses colonization was higher in adult than in juvenile birds, which indicated that the colonization of ontocenoses progresses with age. A significant correlation was found between the presence of fungi, lower values body condition parameters from the urban population (F – degree of fat score, logBM – body mass logarithm, logT – tarsus length logarithm, BM/WL –body mass/wing length, logBM/logWL, BM/TL – body mass/tail length), physiological condition, and age of birds, which may suggest that adults birds with worse condition, and higher haemoglobin level were more often colonized by fungi. No important differences in the fungal colonization were detected between urban and rural areas, thus, the hypothesis that fungal infection may be the cause of decline of sparrows in urban habitats is still to be demonstrated. [ABSTRACT FROM AUTHOR]

Over the last 20 years, a new group of systemic insecticides–the neonicotinoids—has gained prominence in arable systems, and their application globally has risen year on year. Previous modelling studies using long-term data have suggested that neonicotinoid application has had a detrimental impact on bird populations, but these studies were either limited to a single species or neglected to analyse specific exposure pathways in conjunction with observed population trends. Using bird abundance data, neonicotinoid usage records and cropping data for England at a 5x5 km resolution, generalised linear mixed models were used to test for spatio-temporal associations between neonicotinoid use and changes in the populations of 22 farmland bird species between 1994 and 2014, and to determine whether any associations were explained by dietary preferences. We assigned farmland bird species to three categories of dietary exposure to neonicotinoids based on literature data for species diets and neonicotinoid residues present in dietary items. Significant estimates of neonicotinoid-related population change were obtained for 13 of the 22 species (9 positive effects, 4 negative effects). Model estimates for individual species were not collectively explained by dietary risk categories, so dietary exposure to neonicotinoids via ingestion of treated seeds and seedlings could not be confirmed as a causal factor in farmland bird declines. Although it is not possible to infer any generic effect of dietary exposure to neonicotinoids on farmland bird populations, our analysis identifies three species with significant negative estimates that may warrant further research (house sparrow Passer domesticus, skylark Alauda arvensis and red-legged partridge Alectoris rufa). We conclude that there was either no consistent effect of dietary exposure to neonicotinoids on farmland bird populations in England, or that any over-arching effect was not detectable using our study design. The potential for indirect effects of insecticide use on bird populations via reduced food availability was not considered here and should be a focus for future research. [ABSTRACT FROM AUTHOR]

The number of House Sparrows {Passer domesticus) in urban populations has decreased considerably in recent decades in many parts of Europe, particularly in its western part. In Warsaw (Poland), between the 1970s/1980s and the 2000s a decline of almost 50% was recorded. During the same period, Tree Sparrows (Passer montanus), a species also known to have decreased in western Europe, increased significantly in Warsaw. This paper addresses the changes in breeding parameters of both species between the 1980s and the 2000s, i.e., in the period when their numbers changed significantly. Both species have advanced their breeding periods. Despite that the advancement was more significant in the House Sparrow, it did not appear to influence the number of breeding attempts per year, which increased in the Tree Sparrow. In addition, clutch size increased in the Tree Sparrow but not in the House Sparrow. In both species, the level of egg losses did not change, while the nestlings losses decreased, resulting in higher average brood productivity. The annual breeding productivity increased in both species due to fewer breeding losses, and in the Tree Sparrow due to a higher number of broods per season. The results suggest that food availability for sparrow nestlings (likely arthropod resources) in the urban habitats of Warsaw are sufficient to ensure both sparrow species a high level of breeding success. This contrasts with the conclusions of studies of urban House Sparrow populations in western Europe. The strong improvement in Tree Sparrow breeding productivity may be a factor that has determined the growth of its population in recent times. [ABSTRACT FROM AUTHOR]

Food availability is a primary driver of avian population regulation. However, few studies have considered the effects of what is essentially a massive supplementary feeding experiment: the practice of wild bird feeding. Bird feeding has been posited as an important factor influencing the structure of bird communities, especially in urban areas, although experimental evidence to support this is almost entirely lacking. We carried out an 18-mo experimental feeding study at 23 residential properties to investigate the effects of bird feeding on local urban avian assemblages. Our feeding regime was based on predominant urban feeding practices in our region. We used monthly bird surveys to compare avian community composition, species richness, and the densities of local species at feeding and nonfeeding properties. Avian community structure diverged at feeding properties and five of the commonest garden bird species were affected by the experimental feeding regime. Introduced birds particularly benefitted, with dramatic increases observed in the abundances of house sparrow (Passer domesticus) and spotted dove (Streptopelia chinensis) in particular. We also found evidence of a negative effect on the abundance of a native insectivore, the grey warbler (Gerygone igata). Almost all of the observed changes did not persist once feeding had ceased. Our study directly demonstrates that the human pastime of bird feeding substantially contributes to the structure of avian community in urban areas, potentially altering the balance between native and introduced species. [ABSTRACT FROM AUTHOR]

The house sparrow ( Passer domesticus) is well known for conspecific brood parasitism in Europe, and there it is capable of recognizing and rejecting non-mimetic foreign eggs and even mimetic conspecific eggs. Here, we tested the egg rejection of an Asian population of house sparrows by using model eggs, sparrow eggs painted red and sparrow eggs with added brown spots, of which their mimicry to sparrow eggs were quantified by granularity analysis based on avian vision. Surprisingly, house sparrows in Asia did not show any egg rejection. We suggest that the evolutionary equilibrium theory, which was first proposed to explain the absence of egg rejection in some hosts of interspecific brood parasites, may explain the deficiency of egg rejection in house sparrows, as a result of trade-offs between the high rejection costs and the costs of raising conspecific foreign chicks. [ABSTRACT FROM AUTHOR]

The house sparrow, Passer domesticus (Linnaeus, 1758) is closely associated with human habitations and cultivation from historic times. The house sparrow is distributed all over India up to 4000m in the Himalayas. Distribution of House sparrow is not uniform in the country, and in the recent years disappearing of sparrows is also reported from various parts of the world including India. But reliable information on sparrow populations is not available. Less work has been carried out actually for counting and keeping a record of the sparrows. This article summarizes the possible decline in its population through literature review in many parts of the world including India. Several studies carried on house sparrow have cited varied reasons for their decline. So this article also summarized the possible cause and threats for the decline in population. This article compares the role of semi nomadic pastoralist community for conservation of house sparrow with secondary literature. We also tried to suggest the various activities for resolving the issues related with conservation of house sparrow. [ABSTRACT FROM AUTHOR]

Th effect of parasites in natural populations has received increasing attention in recent years. Studies have shown that parasites may play an important part in population ecology due to their potential eff ects on host fi tness. Th e main purpose of the present study was to investigate the eff ect of a nematode parasite (gapeworm, Syngamus trachea) on survival probability of house sparrows Passer domesticus from six natural populations located on 4 islands in the Helgeland archipelago in northern Norway. Infection status was obtained from feces samples collected from 603 house sparrows in the summer and autumn of 2007 - 2011. We also collected data on a visible symptom of severe infection (gasping for air) in 1391 house sparrows in the summer and autumn 2004 - 2011. We took advantage of recent advances in disease modeling in a multi-event capture - mark - recapture framework to account for imperfect observations (state uncertainty). Each dataset was separately analyzed, in both analyses we investigated the relationships of year, island, individual body condition, age class and population density with survival probabilities. Th e relationship between infection (determined by feces egg counts) on annual survival of house sparrows was not statistically significant. However, the probability of annual survival was found to be significantly lower for adult house sparrows exhibiting a symptom of severe gapeworm infection, gasping for air. Th e present study demonstrates that severe infection by a parasite can have a negative relationship with survival probability of short-lived avian hosts in wild populations. [ABSTRACT FROM AUTHOR]

Avian haemosporidian infections (of the genera Haemoproteus, Plasmodium and Leucocytozoon) can regulate passerine populations. Thus, reduction in the number of avian haemosporidian infections in a population, for example in recently introduced hosts, may facilitate host establishment or spread (i.e. enemy release). Alternatively, colonizers could decrease competitive ability of native individuals in the novel range by increasing the prevalence of avian haemosporidians in that native passerine community (i.e. novel weapons). However, whether either or both of these phenomena will occur is difficult to predict because infection risk can be highly heterogeneous and dependent upon the interaction of biotic and abiotic factors at the microclimate level, especially because of the important role of vectors for these parasites. Here, we describe which factors best predicted avian haemosporidian prevalence in populations of house sparrows Passer domesticus introduced to Kenya. House sparrows inhabit an invasion gradient in Kenya; they were introduced via the eastern port city of Mombasa in ˜ 1950 and have since spread west-ward across the country. This range expansion gave us the opportunity to examine how parasite prevalence changes over small spatiotemporal scales and what role is played by environmental and individual traits. Among all individuals, body mass was the strongest predictor of infection, with larger house sparrows being more likely to be infected. At the population level, capture month, precipitation (higher prevalence with more rainfall), and population age (increasing prevalence with increasing time since introduction) were important risk factors. Overall, haemosporidian prevalence in Kenyan house sparrows appears to be more strongly associated with individual characteristics rather than with time since introduction as was predicted, though this does not necessarily rule out a role for enemy release or novel weapons in this system. [ABSTRACT FROM AUTHOR]

Hatching failure is widespread in birds despite presumably strong selection against any wasted reproductive effort and yet there have been few attempts at uncovering sources of variation in failure within a species. Here we use 11 yr of data on the frequency of both undeveloped and unhatched eggs in a marked population of house sparrows Passer domesticus to examine the effects of multiple factors hypothesized to affect hatching success in birds including parental identity, phenotype and genotype, as well as several environmental variables. Unhatched eggs were present in 34.3% of 1523 clutches in which at least one egg hatched, and a total of 10.1% of eggs failed to hatch, of which 75.7% had no visible embryo. We found an effect of female identity on the proportion of eggs that developed and an effect of male identity on hatching success, as well as a positive effect of egg size on both the proportion of eggs that developed and hatching success between females. Neither the proportion of eggs that developed nor hatching success varied according to time of season or weather conditions, clutch size, the age of either parent, the size of the male's black bib, female size, female heterozygosity or the genetic similarity between members of a pair. There was also no positional bias in the occurrence of undeveloped eggs, although undeveloped eggs were more common among birds nesting at low density. Our results suggest that hatching failure in house sparrows has few environmental components and is primarily influenced by intrinsic differences among individuals. [ABSTRACT FROM AUTHOR]

Ecological conditions are likely to change with increasing urbanization, influencing the demography and size of animal populations. Although one of the most tightly linked species to humans, the house sparrow has been suffering a significant decline worldwide, especially in European cities. Several factors have been proposed to explain this conspicuous loss of urban sparrows, but studies evaluating these factors are usually restricted to Britain where the decline was very drastic, and it is unclear whether similar or different processes are affecting urban populations of the species elsewhere. In this study we investigated the reproductive success of urban and rural sparrows in a central European country, Hungary where our census data indicate a moderate decline during the last decade. We found that rural pairs produced more and larger fledglings than suburban pairs, and the difference remained consistent in two years with very contrasting meteorological conditions during breeding. This difference is likely explained by habitat differences in nestling diet, because we found that 1) rural parents provided large prey items more often than suburban parents, 2) birds from differently urbanized habitats produced fledglings of similar number and size in captivity under identical rearing conditions with ample food for nestlings, and 3) in a cross-fostering experiment, nestlings tended to grow larger in rural than in suburban nests irrespective of their hatching environment. These results agree with those found in a recent British study, indicating that poor nestling development and survival due to inadequate diet may be widespread phenomena in urbanized habitats. [ABSTRACT FROM AUTHOR]

The article presents a study which describes the levels of heavy metals in House Sparrows from the rural and urban habitats in southern Finland. House Sparrow has declined by two thirds over the last two decades. The study indicates that heavymetal pollution is a major contributor to the decline of House Sparrows due to the high level of heavy metal concentrations found in the livers of the Sparrow. It implies that pollution is more pronounced in urban environments and even its indirect effect could still contribute to bird declines and low bird populations.

Passive integrated transponders (PITs) are increasingly used to study behaviour in small passerines. However, to ensure the reliability of such studies, knowledge of long-term fitness consequences of equipping passerines with PITs is crucial. We quantify the effects of fitting PITs, injected subcutaneously or glued to colour rings, on fitness in house sparrows Passer domesticus. Relative annual fitness was assessed with the delifing method as an individual's annual contribution to population growth rate. We found no evidence for adverse fitness effects in individual birds fitted with PITs compared with individuals without PITs, independent of the methods of fitting the tags. Our results provide a solid basis for the assumption that such logging devices are safe to use in small passerines and that PITs will most probably not affect the outcome of studies with respect to population dynamics and fitness components. [ABSTRACT FROM AUTHOR]

We began our studies of House Sparrow (Passer domesticus) biparental care in the mid-1990s by applying the classic Margaret Morse Nice field technique of color-banding individuals. Over the ensuing summers, we slowly accumulated quantitative provisioning records for 100 broods, even as we commenced a series of experimental manipulations. Provisioning data showed parental fitness, as expressed by offspring recruitment into the local breeding population, to be shaped mainly by the adults' ability to deliver enormous insect prey items. It also turned out that production of robust and competitive fledglings routinely involves losing one or more nestlings (brood reduction in 42% of 1,000 multi-chick families). Recruitment success was compensated for the death of an offspring if the subsequent reallocation of food enables surviving nest-mates to gain at least 2 g more before fledging. Video samples showed that parents of day 3 broods favored larger siblings, even though brood reduction typically occurs on ~day 4, suggesting that adults participate actively in promoting some offspring over others. The social dynamic affecting how parents work as a team during provisioning does not fit the pattern expected if partners negotiate actively with one another, but points more toward the likelihood of "sealed bids." Specifically, experimental handicapping of individual parents (tail-weights and hormone implants) indicates partners operate quite independently during brood-rearing. We are now extending our experiments into the incubation phase, where parents are probably better-informed about partner activities, thus potentially able to adjust to fluctuating contributions. Finally, behavioral rules affecting food deliveries seem to differ for females and males. Females normally increase provisioning as the brood ages, but males do not. However, when broods received supplemental nutrients, males matched the female upsurge, accelerating their deliveries by 25%, showing they usually work well below capacity. [ABSTRACT FROM AUTHOR]

The article discusses a study examining the predatory role of the Eurasian Sparrowhawk in the declining population of House Sparrow in Great Britain. Evidence of decline among prey species of sparrows has been reported in the data published by the Garden Bird Feeding Survey (GBFS) of the British Trust for Ornithology. Statistical information illustrating the differences in temporal trends in Eurasian Sparrowhawk incidence and House Sparrow population data between rural and urban sites studied are noted.

Predation cost (Pc) is often regarded as a pivotal component determining foraging behavior. We hypothesized that variations in two of its major constituents, predation risk (μ) and the marginal value of energy (∂Fs/∂e, where Fs is the survivor's fitness and e represents the amount of acquired energy), will translate into variations in patch use behavior of ground-foraging birds. We studied patch use behavior of House Sparrows (Passer domesticus), as affected by the proximity to shelter, in two large outdoor aviaries. Proximity to shelter should affect μ. We manipulated the birds' flight performance by clipping primary flight feathers from their wings to increase μ, but the clipping may also increase ∂Fs/∂e. To help distinguish between the birds' response to these confounding effects, we further augmented food in the aviaries to reduce ∂Fs/∂e. Patch use, as measured by giving-up densities (GUD, the amount of food left behind in a resource patch following exploitation) was affected by distance from shelter only slightly and mainly when the birds were feather-clipped and food was not augmented. Food augmentation had a homogenizing effect on foraging costs by increasing GUDs and washing out the effects of distance and feather clipping. We argue that t' increases with distance from shelter but that, for the highly urban House Sparrow, this increase is only slight. Feather clipping then increased μ further to the point at which patch use discernibly decreased with distance from shelter. Our experimental manipulation of feather clipping also acted to increase ∂Fs/∂e and resulted in an overall lowering of GUDs. The seed augmentation counteracted the effect of feather clipping on ∂Fs/∂e, allowing the birds to reduce their foraging efforts and washing out the qualitative effect of μ with respect to distance from shelter. [ABSTRACT FROM AUTHOR]

1. The widespread declines of farmland birds have generally been linked to agricultural intensification. We tested the hypotheses that (i) changes in agricultural policy, through its effects on agricultural intensification and (ii) regional differences in agricultural intensification affect temporal and spatial population trends of farmland birds in Sweden. 2. We analysed regional bird population trends (1976–2003) for seven common farmland bird species: the migratory lapwing Vanellus vanellus, skylark Alauda arvensis, starling Sturnus vulgaris and linnet Carduelis cannabina and the resident tree sparrow Passer montanus, house sparrow P. domesticus and yellowhammer Emberiza citrinella. We identified three periods of agricultural policy in Sweden between 1976 and 2003: the intensification period (i.e. 1976–87; promoting increased production), the set-aside period (1987–95; promoting extensification of farming) and the Common Agricultural Policy (CAP) period (1995–2003; promoting increased production). Population trends were compared between three types of Swedish farmlands: open plains (intensive farming with a marked intensification), mosaic farmlands (i.e. farmland-dominated forest mosaics, less intensive farming, but show moderate intensification) and forest regions (i.e. forest-dominated farmlands with low intensity farming and extensification/abandonment). 3. The four migrants displayed clear significant trend switches between the policy periods, with declines in the ‘intensification period’ and the ‘CAP period’ and less negative or even positive population trends in the ‘set-aside period’. The population trends of the three resident species showed no clear pattern in relation to agricultural policy periods. 4. All species except tree sparrow displayed significantly different population trends between farmland regions. Four species (lapwing, skylark, linnet and house sparrow) declined most in the open plains and the forest regions, whereas two species (starling and yellowhammer) declined most in the mosaic farmlands. 5. Synthesis and applications. Large-scale changes in agriculture policy have a strong potential to change the present poor state of farmland biodiversity as shown by the generally positive population trends in the ‘set-aside period’. It also suggests extensification to be beneficial to farmland birds. However, in regions of low profitability and an already ongoing extensification, a further extensification will lead to loss of both farmland habitat and bird diversity. In such regions mixed farming needs to be retained and hence should be supported. [ABSTRACT FROM AUTHOR]

• Patch diversity was smaller on consolidated sites, with arable fields prevailing. • Bird diversity and abundance of most species were higher on non-consolidated sites. • Only Eurasian Skylark and Common Stonechat were more abundant on consolidated sites. • Land consolidation negatively affects birds' European conservation value. • Land consolidation should not be performed at Natura 2000 sites. Land consolidation can negatively affect biodiversity, as it is usually followed by the expansion of arable land, a decrease in crop and land cover diversity, and an increase in the application of agrochemicals. The aim of our study was to compare the species' composition and abundance of farmland birds, as well as habitat structure, on consolidated and non-consolidated sites in Goričko, NE Slovenia. Habitat diversity was much lower on consolidated sites compared to non-consolidated ones, with arable fields and associated habitats (e.g. grass field margins, field tracks) prevailing on the former. Non-consolidated sites held higher proportions of different types of meadows, hedgerows, solitary trees, succession and traditional orchards. Farmland bird diversity and the abundance of a majority of farmland bird species were higher on non-consolidated sites. The only two exceptions to this were the Eurasian Skylark and the Common Stonechat, which were more abundant on consolidated sites. Both of the species suffered population declines at Goričko in the period 1997–2016, bringing into question the suitability of intensively managed arable fields as their breeding and foraging habitat. Individual species' regression analysis revealed that the most influential positive explanatory variable for the presence of Red-backed Shrike, Tree Sparrow and Common Whitethroat was non-consolidated, extensively managed mosaic landscape, whereas for the Yellowhammer this explanatory variable was superseded only by forest islands without traditional orchards. Land consolidation, as performed in Slovenia, negatively affects farmland bird diversity and its European conservation value, which is why it should not be performed on Natura 2000 sites, designated for nature conservation. [ABSTRACT FROM AUTHOR]

Current urban policies are associated with deep changes in urban structures, which may impoverish urban biodiversity. A major concern is the disappearance of nesting sites for wild vertebrate species living in urban areas. New urban structures without any cracks or cavities may especially preclude cavity nesters from breeding in cities and they may cause population declines. In that context, we experimentally investigated this question in an urban exploiter bird species (the house sparrow Passer domesticus), which is dramatically declining in most European cities. To test if the lack of cavities is limiting house sparrow populations in urban areas, we equipped 11 sites along an urbanization gradient with nest boxes and we then evaluated the rate of occupancy of these nest‐boxes. This urbanization gradient was characterized by very rural places (isolated farms) and moderately urbanized areas (town of medium size, i.e. 60 000 inhabitants). Surprisingly, rural nest boxes were more occupied than urban ones, suggesting that cavity availability is probably more constraining in rural areas relative to urban ones. Therefore, our study suggests that urban house sparrow populations are probably not constrained by a lack of nesting sites in medium size cities with urban designs similar to our city of interest (Niort, western France). This hypothesis definitely needs now to be tested in further urban landscapes (e.g. large cities and urban landscapes with other architecture and management policies). [ABSTRACT FROM AUTHOR]

Discusses a report in the 29 August issue of 'Nature' that discusses reasons for the decline in house sparrow populations in rural areas of England. Identification of overwinter survival rates by David Hole of the University of Oxford's Edward Gray Institute of Field Ornithology; Results from a survey of farmers in Oxfordshire; Suggestion that winter food supply is likely the cause; Other contributors, such as changes in agricultural practices.