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Based on the analysis of egg collections of different ecological groups of birds and various literature sources, a summary of scientific studies on morphological adaptations related to the color of eggshells in birds is given. Eggshell color in birds is a morphological adaptation with a masking function that depends on nesting conditions. The article examines egg collections of birds with an open nesting type: Eurasian skylark (ground-nesting), Eurasian chaffinch (crown-nesting), and Red-backed shrike (bush-nesting). The study confirmed the high variability of eggshell color in birds with an open nesting type, which allows clutches to be invisible which contributes to successful nesting. The correlation between the location of the nest and the color of the eggshells of the studied bird species was analyzed, and the peculiarities of this correlation were determined. [ABSTRACT FROM AUTHOR]

Organic farming is considered beneficial for farmland biodiversity. However, it is often unclear what specific factors are underlying the biodiversity benefits of this farming practice. The positive effects may be driven by factors acting at the field level represented by, for instance, the absence of pesticides, or by the factors acting at the level of entire farms represented by a higher diversity of crops and intercrops types, and higher share of semi-natural landscape elements. Distinguishing between these two groups of factors is difficult because they are confounded in heterogeneous landscapes consisting of small arable fields. However, their separation is crucial to understand the origins of organic farming effectiveness. The landscape in those Central and Eastern European countries that have undergone collectivization, such as Slovakia, Czechia or Lithuania, consists of large fields cultivated under either conventional or organic regime. These circumstances are suitable to assess the sole influence of in-field factors providing potential biodiversity benefits of organic farming. For this purpose, we selected a study area in the lowlands of the south-western Slovakia, where conventional and organic fields were situated in close proximity. Such a spatial arrangement was suitable to examine the possible influence of farming practice (i.e. organic vs. conventional) itself, minimising the influence of landscape elements. We focused on a single cereal crop, winter wheat, cultivated on both organic and conventional fields. Here, we counted the breeding abundance of the Eurasian Skylark (Alauda arvensis), a farmland specialist bird closely associated with arable fields providing both breeding and feeding habitat for this species, which may be considered as a farmland biodiversity indicator. Skylark counts were higher in organic than in conventional wheat fields throughout the season. This difference was statistically related to a higher abundance of invertebrates in samples collected in organic fields than in conventional fields. However, Skylark counts were also related to sparser crop cover in organic fields, especially at the end of the season. Sparser crop cover may improve nesting conditions and facilitate foraging. Our results indicate that organic farming may have a positive impact even at the field-level. The benefits for the Skylark, and possibly for the other farmland organisms, can be provided by the joint effects of the absence of pesticides and a suitable vegetation structure. Organic farming can thus be a suitable agri-environmental measure within the Common Agricultural Policy even in intensively used landscapes dominated by large fields.

Background & Introduction The Medical Research Council National Survey of Health and Development (NSHD) is the oldest and longest-running of the British birth cohort studies. In 2018 we launched the Skylark Wiki, a central metadata repository and the first port of call for any data sharing queries. In 2023 we utilised the HDRUK funding initiative to work with our advisory group and research community to improve the transparency of our data access process and make the content more accessible. Methods We conducted a focus group session with the NSHD Participant Advisory Panel to understand their views on the data sharing process and whether the information we provided them, sufficiently explained how their data are shared. We also sent out a questionnaire to all Skylark Users to identify areas of improvement. Lastly, we undertook an audit of the website’s content and used Google Analytics to see how Users navigated across the site. Combining all this information we identified areas requiring improvements, from the point of view of our stakeholders, and comparing these to the requirements indicated in the HDRUK Transparency Standards we mapped out updates to the Skylark Wiki. The work was carried out by an external agency (Aubergine262 Ltd). Results To increase transparency and searchability, we improved the flow diagram of the data sharing process to include links to the relevant web pages. We also created guidance to explain why the information in the data request application form is being asked. As feedback from Skylark Users suggested difficulties in finding the required information, the navigation has been updated. We have also changed the layout of the front page to include navigation boxes that takes users straight to the content. The NSHD Advisory Panel reinforced the notion of trust that study participants place in the study and its approach to data sharing. They confirmed the information provided on data sharing was adequate and appreciated that this information was placed on the main study website (https://nshd.mrc.ac.uk/) for their benefit. Initial feedback from Users indicates that it is easier to find information on the website. We will keep monitoring access to the website, the number of queries, and data access requests to evaluate long-term benefits. We have changed the sitemap and added in large link boxes, to make it easier to find the different sections. We hope this will improve the searchability of the site so users can find information they required. We hope this will therefore lead to fewer emails and correspondence between the data sharing team and users. We have also updated the flow diagram of the data sharing process to include links to the web pages which are related to that section. We hope this will help the users find the information they require. Conclusions The new Skylark data-sharing website supports easier navigation providing a better User experience. In return, this should lead to fewer queries from Users. The website will be easier to maintain having changed the content management system from a Wiki to WordPress. WordPress requires less technical knowledge, allowing more staff to contribute to regular maintenance. References • Skylark data-sharing website: https://skylark.ucl.ac.uk/NSHD/ • Aubergine: https://www.aubergine262.com/

The present investigation was aimed to improve the contemporary information about morphometry and diet of Oriental skylark Alauda gulgula nestling from hatching to 8th day very carefully during the breeding season (April, May, June, and July) 2019, in district Bajaur. A total of 70 nestlings of 22 nests were studied systematically. The eggs were hatched out both from the middle point and blunt end. All the eggs were hatched asynchronously with closed eyes and a naked body. They opened their eyes on average after 3.27±0.4 days of hatching. Their wing and tail feathers grew on an average of 3.8±0.3 day of age. On the 8th day, their average morphometry (cm) was: body length 6.7±0.1, wingspan 4.8±0.1, tail feathers 0.8±0.7, beak 0.7±0.3, chest 2±0.1, legs 2.02±0.5, middle claw 0.2±0.04, hind claw 0.4±0.04, and average body weight (g) 20.7±0.7. From hatching till the 3rd day of age, they were fed totally with larvae of arthropods, most1y Lepidoptera and Coleoptera (40%), Hymenoptera (12%) and Diptera (8%). However, adults and grains were not fed. Nestlings (4th day age) were fed by adults (32%), larvae (69%), and grains (2%). While the chicks were fed mostly by adults (72%), with larvae (23%) and grains of seed (5%). Significant differences were present in the growth of all traits, morphometry, diet, and food collection sites. However, no difference in feeding was noted. The main loss of nestlings was by mammalian predators and grazing and cutting of local crops. Awareness about the protection strategy of skylark from egg laying till fledging is required among locals and farmers. [ABSTRACT FROM AUTHOR]

The skylark is a tiny brown bird with a small crest on its head. It is slightly larger than a sparrow and is popularly known for its uninterrupted song during its upward flight. The bird is found in most parts of England and many European countries. A closer examination of English poetic tradition reveals that several English poets have anthologised this tiny bird, including famous poets such as Wordsworth, Shelley, Hopkins, Meredith, Rossetti, Rosenberg, and C Day-Lewis. The late poet laureate Ted Hughes also wrote about the skylark in our times. Even Shakespeare and Goethe have eulogised the skylark in their plays. Since Thomas Hardy has written a poem about 'Shelley's skylark,' it is evident that traditionally 'To a Skylark' by Shelley is the most popular of all 'Skylark' poems. However, Hughes's poem on skylark merits our attention because it is entirely different from the general trend of all other skylark poems written until his time. Therefore, this study explores how the skylark became a symbol of poetic inspiration for different generations of poets by analysing the two famous poems on skylark written by Shelley (1792-1822) and Hughes (1930-1998). While Shelley depicts the skylark as a pure spirit of joy, Hughes considers it an embodiment of cosmic energy resulting from the bird's struggle for flight against the earth's gravitational pull. Therefore, the different perceptions of Shelley and Hughes about the skylark constitute the essence of this discourse. [ABSTRACT FROM AUTHOR]

This article reads twentieth-century Nature Writing as an inquiry into limits of narrative in confrontations with nonhuman animals. I argue that in their nonfiction accounts of nonhuman animals, J. A. Baker and Emma Louise Turner settle on forms that express what it is like to be a peregrine falcon or a skylark. Subsequently, however, readers are given to understand the degree to which the imagined identification falters. Far from aspiring to mimetic accounts of the environment, I approach these texts as sophisticated negotiations of differential form. From this point of view, narrative is a temporary effect set apart from alternative forms. By considering 'disnarration' as much as narration, the incompatibility of environmental themes and narrative form emerges as an affordance in its own right. [ABSTRACT FROM AUTHOR]

Transition from conventional energy into a system based on renewable energies was decided in Germany in 2002. Its implementation was accompanied by a controversial discussion about food safety, biodiversity, and landscape change. This study assesses potential changes in skylark occurrence caused by a spatial expansion of bioenergy crops in the administrative district of Schwäbisch Hall, Germany, using a Generalised Linear Habitat Model approach combined with remotely sensed land use information. Predictions for the occurrence of skylarks were developed for the land use distribution in 2011, and a close to reality bioenergy scenario with reduced crops. Prediction of skylark territories based on the land use classification of 2011 resulted in 46 269 territories. Skylark territories for the bioenergy scenario resulted in 36 472 territories, which as 8797 fewer skylark territories, represents a decline of nearly 20%. Our study helps elucidate and quantify the effects of spatial extension of bioenergy crops on skylark. [ABSTRACT FROM AUTHOR]

While many studies have illustrated the decline of animal populations—particularly of farmland birds—the statistical analyses, design, and protocols used have raised some concerns and criticism. Using a 27-year dataset (1996–2022) based on recording the number of skylarks (Alauda arvensis) at 160 longitudinal count points, our study confronts two approaches commonly used to model long-term trends. The first uses a single model (based on a priori ecological knowledge), while the second is an a posteriori approach that relies on a multi-model selection among candidate models that account for probability distributions to describe the error structure. Here we investigate whether the statistical distribution of modelled variables and the method of including covariates in the model affect trend estimates. With a large amount of data and in the case of underdispersion, we found that the model distribution used had no impact on the estimation of the long-term trend. Moreover, adding confounding covariates did not change or improve the trend estimation, at least when data were obtained from a well-designed protocol (our case). In contrast to other studies reporting an effect of the model's distribution on long-term trends, especially in the presence of overdispersion, our results offer a new perspective on the presence of underdispersion, where simple models perform equally well as complex ones. Further research is now needed on multiple species data or on smaller data sets to check the generality of our findings. • We compare a priori single- to a multi-model approach to estimate a temporal trend. • We use a 27-year dataset of 160 transect count points of skylark in a farmland area. • Model distribution has no effect on trend estimate in case of underdispersion. • Covariates have no effect on trend estimate with data from a well-designed protocol. [ABSTRACT FROM AUTHOR]

Abstract The growing concern about future challenges of energy security and climate change has led to the expansion of renewable energy production, with a special emphasis on wind power. Despite the environmental advantages of wind power, it's important to assess the impacts caused by the presence of wind farms on wildlife, particularly on species also affected by habitat loss and degradation. In Mediterranean Europe, the skylark (Alauda arvensis) is a declining passerine that breeds in mountain habitats vulnerable to the abandonment of traditional management practices and climate change. We have created a spatially explicit agent-based model (ABM) in order to replicate the selection of territories, evaluating the effect of wind farms on the mortality rate of breeding males. We were especially interested in assessing the mortality rates related with the interplay between habitat loss due to socio-ecological change and increasing wind power using alternative strategies: adding wind turbines or substituting existing wind turbines by more powerful ones, i.e. repowering. Several known aspects related with the risk of collision of A. arvensis with wind turbines were considered, particularly regarding the male habitat selection and behaviour displayed throughout the breeding season. By simulating a sequential contraction of suitable habitat for the species, we found a substantial increase in the breeding territories superimposed to the wind farm influence zone. In these conditions males' relative mortality was predicted to suffer significant increases. For equivalent wind power, adding wind turbines produced significant increases in the males' relative mortality, whereas repowering didn't. Based on our findings we propose repowering as a defensible strategy to increase wind energy production without increasing A. arvensis collision risk. We highlight that this strategy might also benefit other vulnerable bird and bat species associated with declining habitats of mountain ridges in the Mediterranean region. Graphical abstract Image 1 Highlights • Alauda arvensis is a declining species in mountains of the Mediterranean region. • Increasing demands of renewable energy are expanding wind farms in the stated region. • Alauda arvensis population was predicted to decrease due to socio-ecological change. • Males' mortality risk rises with population drop but not with wind power rise. • Repowering is a win-win strategy: power rise, without significant rise in mortality. [ABSTRACT FROM AUTHOR]

The decline of farmland birds across Europe is a well‐documented case of biodiversity loss, and despite land stewardship supported by funding from agri‐environment schemes (AES), the negative trends have not yet been reversed.To investigate the contribution of AES towards farmland bird conservation, we compared abundance of five farmland bird species across 13 years and 53 farms (158 farm years = AES, 72 farm years = non AES) in Northeastern Scotland (UK), a region with relatively mixed farmland.Between 2003 and 2015, on both AES and control farms, skylark (Alauda arvensis) showed a nonsignificant decline, and tree sparrow (Passer montanus) and yellowhammer (Emberiza citrinella) nonsignificant increases, whereas reed bunting (Emberiza schoeniclus) and linnet (Carduelis cannabina) populations remained relatively stable.We did not detect a significant association between AES and avian abundance or population trends for any of these species, but there were positive associations with some AES management options.Possible explanations for the lack of a significant AES‐bird abundance association include poor uptake of the best AES options for farmland birds, suboptimal implementation, spill‐over effects from AES onto control farms, and the relatively good state of farmland habitats outwith AES in Northeastern Scotland.Synthesis and applications. We documented a weak effect size of participation in agri‐environment schemes on farmland bird abundance. We therefore recommend future monitoring studies be designed after consulting a power analysis. Among different land management options, we found that species‐rich grasslands, water margins, and wetland creation enhanced breeding bird abundance, highlighting the importance of relatively undisturbed herbaceous or grassland vegetation for farmland conservation. We documented a weak effect size of participation in agri‐environment schemes on farmland bird abundance. We therefore recommend future monitoring studies be designed after consulting a power analysis. Among different land management options, we found that species‐rich grasslands, water margins, and wetland creation enhanced breeding bird abundance, highlighting the importance of relatively undisturbed herbaceous or grassland vegetation for farmland conservation. [ABSTRACT FROM AUTHOR]

Context: The current Common Agricultural Policy (CAP) of the European Union includes three greening measures, which are partly intended to benefit farmland biodiversity. However, the relative biodiversity effects of the greening measures, including joint effects of landscape context, are not well understood.Objectives: We studied the effects of increasing crop diversity, proportions of production grasslands and fallows, corresponding to CAP greening measures, on open farmland bird diversity, whilst controlling for the effects of distance to forests, field edge density and proportion of built-up areas.Methods: We surveyed open farmland birds using territory mapping in Southern Finland. We modelled effects of greening measures and landscape structure on farmland birds (7642 territories) using generalised linear mixed models.Results: Increasing proportions of grasslands increased farmland bird species richness and diversity in open farmland, whereas increasing proportions of fallows increased bird diversity. Increasing crop diversity benefited individual species, but not species richness or diversity. Increasing field edge densities consistently increased the species richness of all farmland species, in-field nesters and non-crop nesters, as well as total farmland bird diversity. The relative effect of edge density was much stronger compared to the three greening measures.Conclusions: Our results show that promoting fallows and grasslands, in particular grazed grasslands and various types of semi-natural grasslands, has the highest potential to benefit farmland bird diversity. Maintaining or increasing field edge densities, currently not supported, seems to be of even more benefit. In open farmland, with little or no field edges, fallows and grasslands are particularly beneficial. [ABSTRACT FROM AUTHOR]

Abstract: Agricultural field crops differ in their vegetation height, coverage, and temporal development, affecting the abundances of bird species, which are often used as bioindicators. Although this relationship has been observed, no significant methodology exists to describe the dynamics of field crop growth on a landscape scale in connection with the abundance of indicator bird species that allows meaningful interpretation of bird abundance data with respect to crop vegetation parameters during the breeding season. In a field observation program, we monitored 2,900 ha of agricultural landscape to represent both the crop growth processes and the bird abundances. We measured these two parameters in the study area, dominated by winter wheat, winter rapeseed, maize, and fallow fields, and adapted the moving window approach to a new method of “moving window growth” to describe the dynamic development of height and coverage of the crops over time. Simultaneously, Skylarks (Alauda arvensis) territorial behavior was measured concurrently on the same fields and crops. Their dynamic abundance was documented over the breeding season. To test the relationship between crop growth and development and bird abundance, we applied a generalized linear model (GLM) in two ways: (a) without differentiation of crop species and (b) with differentiation of crop species. We found significant relationships between bird abundance and vegetation height and coverage with respect to both individual parameters and their interactions, even without differentiation of the agricultural crops. In general, increasing vegetation height and coverage, especially the interaction, led to decreasing bird abundance values. The model quality increased significantly by including differentiation of specific crops as an explanatory variable indicating a non‐homogenous situation between crops. Separate models for individual crop species revealed larger differences in model quality with best and least goodness of fit values for fallow fields and winter rapeseed, respectively. Because of the clear interactions between bird abundance, type of field crop, and vegetation height and coverage, it follows that both habitat suitability assessments of arable fields and the definition of favorable vegetation structures for farmland birds should be crop species‐specific. [ABSTRACT FROM AUTHOR]

Abstract: The biocomplexity approach refers to a fully integrated social‐ecological systems (SES) simulation that represents bidirectional feedbacks between social and ecological components. This method is essential to accurately assess impacts of economy and policy on SES such as agroecosystems, where feedbacks between the drivers and impacts of cropping changes need to be simulated. Here we exemplify the biocomplexity approach using energy maize, which is becoming an important source of bioenergy in Europe, and thus, might cause a significant change in land use with knock on‐effects for wildlife. The integrated simulation tool consisted of a farmer decision‐making agent‐based model fully coupled to the Animal Landscape and Man Simulatin System (ALMaSS), an agent‐based simulation system for predicting impacts of land use on a range of Danish wildlife species: the brown hare (Lepus europaeus), the grey partridge (Perdix perdix), the skylark (Alauda arvensis), a carabid beetle (Bembidion lampros), a linyphiid spider (Erigone atra) and the field vole (Microtus agrestis). This was used to assess the impacts of increasing demand on energy maize on the six animal species. Two types of experimental scenarios were evaluated, with and without feedback between the social and ecological system. The assessment of species responses was based on changes in population size, abundance and occupancy. The response to the cultivation of energy maize was negative for three vertebrate species (skylark, hare and field vole) and positive for partridge and the two invertebrate species. The feedback scenarios showed that the incorporation of information from ecological system to the farmer decision‐making affected both a trend in area cultivated with energy maize as well as the animal responses. Synthesis and applications. Fully coupling agent‐based decision‐making and environmental simulation allows a detailed representation and integration of both social and ecological components of agricultural systems at proper spatial and temporal scales as well as of dynamic feedbacks between the two systems. By employing easy to interpret measures of changes in abundance and spatial occupancy of animal species, the simulation results could inform and simplify decision‐making on expected impacts of economy and policy regulations on wildlife. [ABSTRACT FROM AUTHOR]

From 1998 to 2015, 22 490 fully grown Skylarks were captured and ringed, using mist nets, from October to mid November, along the southern Tyrrhenian coast of Italy. We estimated fat loads and theoretical flight ranges for individual birds, using recorded body mass and visible fat score. The size-specific fat-free body mass, as the body mass of birds with no visible subcutaneous fat deposits, was estimated for all categories of wing length, verifying any differences between males and females identified using wing length; body mass (to 0.1 g) and visible fat score (values 0-6) were recorded in the field. Males were significantly heavier than females and more often had high scores of visible fat. Only a few birds had high fat scores (classes 5 and 6) and the proportion of individuals with no visible fat (class 0) was very low: most birds of both sexes fell into classes 3 or 4. Fat scores were positively correlated with the corresponding average body mass. The predicted flight range indicated that 70% of Skylarks captured would be unable to fly farther than 800 km: they would be able to reach their wintering grounds, spend the winter in Italy or reach the North African coast after a refuelling stop. [ABSTRACT FROM AUTHOR]

Specific protection goals (SPGs) comprise an explicit expression of the environmental components that need protection and the maximum impacts that can be tolerated. SPGs are set by risk managers and are typically based on protecting populations or functions. However, the measurable endpoints available to risk managers, at least for vertebrates, are typically laboratory tests. We demonstrate, using the example of eggshell thinning in skylarks, how simulation can be used to place laboratory endpoints in context of population-level effects as an aid to setting the SPGs. We develop explanatory scenarios investigating the impact of different assumptions of eggshell thinning on skylark population size, density and distribution in 10 Danish landscapes, chosen to represent the range of typical Danish agricultural conditions. Landscape and timing of application of the pesticide were found to be the most critical factors to consider in the impact assessment. Consequently, a regulatory scenario of monoculture spring barley with an early spray treatment eliciting the eggshell thinning effect was applied using concentrations eliciting effects of zero to 100% in steps of 5%. Setting the SPGs requires balancing scientific, social and political realities. However, the provision of clear and detailed options such as those from comprehensive simulation results can inform the decision process by improving transparency and by putting the more abstract testing data into the context of real-world impacts. [ABSTRACT FROM AUTHOR]

The rapid development of wind energy may have negative effects on bird populations, including collisions with turbines, displacement due to disturbance or habitat loss, indirect effects of reduced breeding success and barrier effects. This challenging conservation issue has attracted a great deal of interest, but the noise generated by turbines has been largely overlooked. Here, we studied acoustic behaviour of Skylarks Alauda arvensis in relation to wind farm start-up to assess whether a change in song parameters can indicate a deterioration in the acoustic environment. We recorded territorial males displaying close to operating and non-operating turbines and at a control site without turbines. In the following breeding season, we undertook replications at the same sites, except that the non-operating turbines were now in operation. We found that Skylarks displaying at the wind farm were affected by wind turbine noise. Males singing close to operating wind turbines sang higher-frequency songs than males from a control site and those that displayed near non-operating turbines. In addition, an upward frequency shift in songs was observed when non-operating turbines started to operate in the consecutive season. We therefore conclude that the frequency shift observed did not result from turbine presence, but from the noise they started to generate. This shows that a change in song parameters may reliably and within a relatively short time indicate a significant deterioration of the acoustic environment as a consequence of wind farm start-up. This may help conservation biologists to identify species and populations that are particularly susceptible to wind farm noise. [ABSTRACT FROM AUTHOR]

Background: Physiological preparation for reproduction in small passerines involves the increased secretion of reproductive hormones, elevation of the metabolic rate and energy storage, all of which are essential for reproduction. However, it is unclear whether the timing of the physiological processes involved is the same in resident and migrant species that breed in the same area. To answer this question, we compared temporal variation in the plasma concentration of luteinizing hormone (LH), testosterone (T), estradiol (E2), triiothyronine (T3) and body mass, between a migrant species, the Eurasian Skylark (Alauda arvensis) and a resident species, the Asian Short-toed Lark (Calandrella cheleensis), both of which breed in northeastern Inner Mongolia, China, during the 2014 and 2015 breeding seasons. Methods: Twenty adult Eurasian Skylarks and twenty Asian Short-toed Larks were captured on March 15, 2014 and 2015 and housed in out-door aviaries. Plasma LH, T (males), E2 (females), T3 and the body mass of each bird were measured every six days from March 25 to May 6. Results: With the exception of T, which peaked earlier in the Asian Short-toed Lark in 2014, plasma concentrations of LH, T, E2 andT3 of both species peaked at almost the same time. However, Asian Short-toed Larks attained peak body mass earlier than Eurasian Skylarks. Plasma T3 concentrations peaked 12 days earlier than plasma LH in both species. Generally, plasma LH, T, E2, T3 and body mass, peaked earlier in both species in 2014 than 2015. Conclusions: The timing of pre-reproductive changes in the endocrine system and energy metabolism can be the same in migrant and resident species; however, residents may accumulate energy reserves faster than migrants. Although migration does not affect the timing of pre-breeding reproductive and metabolic changes, migrant species may need more time to increase their body mass. T levels in resident species may be accelerated by higher spring temperatures that may also advance the pre-breeding preparation of both migrants and residents. [ABSTRACT FROM AUTHOR]

The Eurasian skylark Alauda arvensis is very susceptible to the negative effects of wind farms. In northern Portugal, this evidence is particularly severe due to the skylark's preference for mountain breeding habitats where most wind farms are located. Facing the frequent failure of environmental impact assessments ( EIA) to evaluate the cumulative impacts of wind farms on wildlife, this study aimed to develop and test a methodology to quantify local and regional consequences on birds, using skylarks as a test species, taking into account future predictable environmental changes., We propose a spatially explicit dynamic approach that combines the results from multiple modelling techniques under a common framework to assess the local and cumulative regional impacts of wind farms on skylark populations. This includes the following: (i) modelling the local impact of wind farms (in terms of collision mortality) on the skylark population dynamics by developing an index for quantitative assessments, (ii) determining the actual and future skylark breeding distribution across northern Portugal and (iii) integrating the above contributions in an emergent spatially explicit regional representation to capture the ecological cumulative consequences as a whole., The simulations show an increasing average local impact for the skylark breeding populations directly affected by wind farms, expressed in mean number of collision fatalities per UTM study unit (1 km2), representing 1·3% of the local breeders in 2006 and 4% in 2026., The distribution area of skylark breeding populations was predicted to decrease around 4·5% throughout a period of 15 years, as a result of the scenario of climate and land cover changes in the study area. When combined with a concomitant increase in skylark global mortality ( c. 184%) induced by all wind farms in the study region, the above trend contributes to an intensification of the regional cumulative impact from 1·2% to 3·7% of the total estimated breeding individuals., Synthesis and applications. The proposed modelling framework represents a step forward in evaluating the multi-scale cumulative consequences of wind farms on vulnerable birds, using skylarks as a test species. This could be used in the future to guide monitoring efforts and to improve the applicability of the data bases generated by long-term ecological research and monitoring studies. [ABSTRACT FROM AUTHOR]

The promotion of biodiversity in agricultural areas involves actions at the landscape scale, and the management of cropping patterns is considered an important means of achieving this goal. However, most of the available knowledge about the impact of crops on biodiversity has been obtained at the field scale, and is generally grouped together under the umbrella term “crop suitability.” Can field-scale knowledge be used to predict the impact on populations across landscapes? We studied the impact of maize and rapeseed on the abundance of skylark (Alauda arvensis). Field-scale studies in Western Europe have reported diverse impacts on habitat selection and demography. We assessed the consistency between field-scale knowledge and landscape-scale observations, using high-resolution databases describing crops and other habitats for the 4 km2 grid scales analyzed in the French Breeding Bird Survey. We used generalized linear models to estimate the impact of each studied crop at the landscape scale. We stratified the squares according to the local and geographical contexts, to ensure that the conclusions drawn were valid in a wide range of contexts. Our results were not consistent with field knowledge for rapeseed, and were consistent for maize only in grassland contexts. However, the effect sizes were much smaller than those of structural landscape features. These results suggest that upscaling from the field scale to the landscape scale leads to an integration of new agronomic and ecological processes, making the objects studied more complex than simple “crop ∗ species” pairs. We conclude that the carrying capacity of agricultural landscapes cannot be deduced from the suitability of their components.

Biodiverse areas of traditional low-intensity agriculture in Europe, or ‘High Nature Value’ (HNV) farmland, are supported by European policy and government subsidies. However, HNV areas have declined in extent, contributing to biodiversity decline. If some traditional practices in HNV farmland could be modernised without reducing natural values, this could improve the economic viability of HNV farms, increasing their resilience to economic pressures. Here we compare one traditional and two modernised cereal harvesting methods on machair , an HNV farmed landscape typical of the Scottish islands, focussing on the value of post-harvest stubbles to wintering birds. Following traditional practice, all cereals were mixed species crops comprised of local varieties of small oats, barley and rye. Grain abundance and seed-eating bird use of stubbles was compared across 16 rounds of visits to 15 fields, five under each of three harvest methods: traditional reaper-binder (machinery from 1950–60s), combine-harvesters (1970–80s) and arable silage (1990–2000s). The two forms of harvest modernisation (combine harvester, arable silage) produced stubbles that differed markedly in bird use. Skylark and bunting occurrence, and grain abundance, were 1.7–19 times higher on stubbles following combine harvesting, than on those following arable silage. Unexpectedly, combine-harvester stubbles had similar levels of bird use to those following traditional reaper-binder harvest. Our results suggest that harvesting on machair could be modernised using (older model) combine-harvesters in place of traditional methods, with little impact on stubble value for birds, maintaining this aspect of high nature value. Conversely, modernisation involving more cereals harvested as arable silage, under current practice, is likely to reduce stubble quality for seed-eating birds. Future work could test whether delayed cutting of arable silage might create stubbles of greater value for birds. [ABSTRACT FROM AUTHOR]

Farmland birds are important indicators of the state of biodiversity in rural landscapes, and the occurrence and abundance of birds contribute to their importance as bioindicators. However, the measurement of farmland bird abundance can be difficult. The rapid growth of crop plants in the spring combined with disturbances related to farming practices, such as weed and pest control and other measures, can profoundly change the habitat suitability of arable fields for birds within a short period of time. Consequently, the existing dynamics must be incorporated into the applied methods, and a single value of bird abundance during the breeding season is insufficient to characterise the habitat functions of arable land. The abundance of farmland bird species is influenced by crop specific features, which profoundly change within the breeding season and which we have described using a novel concept called Moving Window Abundance. Based on field surveys in 29 observation areas within arable landscapes, each 1 km 2 , Skylark with territorial behaviour were counted using a mapping method related to the habitats and growth of field crops, such as wheat and maize. To describe the dynamic characteristics of the abundance during the breeding season over the time period from 16 March to 18 July, three methods of Moving Window Abundance were tested: patchy, adjacent and overlapping. These methods differ in the time-space continuity of the considered time window throughout the breeding season. In the Patchy Moving Window Abundance method, we used the exact days in which field surveys were conducted throughout the entire time period of the field surveys. However, with the Adjacent Moving Window Abundance method, the time window included five-day, ten-day and semi-monthly adjacent windows; in the Overlapping Moving Window Abundance method, the time window shifted daily, with five-day, ten-day and semi-monthly overlapping windows used in the calculation procedure. The results indicated that the dynamic nature of Skylark abundance (i) reached a maximum level in the first breeding period in the agricultural landscape and (ii) exhibited large variations in level and time within the various field crops. Therefore, abundance was not described conventionally using a single numerical value but rather using mathematical functions based on the spatial scale of the landscape and habitat. We conclude with recommendations for further research to standardise farmland bird monitoring. [ABSTRACT FROM AUTHOR]

Advances in our understanding of recent farmland biodiversity loss have mainly come from studies in Western Europe. The application of such findings to other regions is questionable, however, and limits the outcomes of management actions. To bridge this knowledge gap, we focused on relationships between farmland bird abundance and sward height and crop type, counting breeding birds in three Central European regions with different agricultural histories and practices: the Eastern Czech Republic, Western Germany and Central Poland. We used the skylark ( Alauda arvensis ) as a model species due to its tight association with open habitats year-round and its commonness in European farmland. Skylarks were more abundant in Poland than in Germany and the Czech Republic, probably due to less intensive farmland management. Mean abundance declined with growing sward height from April to June and slightly declined with the number of fields surrounding study sites in all regions. Autumn- and spring-sown cereals hosted the highest abundance of skylarks in May, with lower abundance in maize, oilseed rape and meadows irrespective of region. This variation in skylark numbers suggests a temporal shift in abundance, probably reflecting movement between crops with optimal sward height. Taken together, these results indicate that skylark habitat use is somewhat conserved over regions and this knowledge can be used in management plans throughout Europe. However, the observed differences in skylark abundance between regions suggest that the regional-specific level of agricultural intensity may affect the delivery of conservation benefits from such plans. [ABSTRACT FROM AUTHOR]

Grass fodder crops are attractive nesting habitats for a suite of declining farmland bird species that nest in taller grass swards. Multiple, early silage harvests cause substantial losses of nests and flightless fledglings, making this widespread crop an influential population sink in temperate farmland. We measured the effects of two simple conservation interventions (raised cutting heights and delayed mowing) designed to increase the reproductive output of a multi-brooded passerine (skylark Alauda arvensis ). Annual reproductive output of independent juveniles (fecundity) was quantified using a stochastic re-nesting model that allowed us to investigate the impacts of a wide range of potential management interventions (varying cutting heights, dates and machinery) at minimal cost. Under typical silage management mean skylark fecundity was only 13–17% of the level required for metapopulation stability (the replacement rate). 12–54% of nests and 28–44% of fledglings survived a typical silage harvest with most losses caused by abandonment of nests covered by cut grass, crushing by wheels or predation soon after mowing. Delaying mowing increased fecundity, but only up to a maximum of 44% of the replacement rate. Raising cutting heights had a negligible impact on fecundity. Asynchrony between nesting attempts (due to predation, starvation and protracted delays between nesting attempts) resulted in few attempts taking place when they could benefit from the interventions. In the absence of mowing, fecundity was only 47% of the replacement rate, due to low reproductive output per nesting attempt, while simulations showed that increasing output per nest would have the largest impact on fecundity. Conservation effort should focus on providing alternative high fecundity breeding and foraging habitats at the landscape scale, to counteract silage fields’ action as a sink for skylark populations in livestock-farming areas. These conclusions are likely to apply to other multi-brooded ground-nesting species. [ABSTRACT FROM AUTHOR]

Many animal species have populations in which some individuals migrate and others remain on the breeding grounds. This phenomenon is called partial migration. Despite substantial theoretical work, empirical data on causes and consequences of partial migration remain scarce, mainly because of difficulties associated with tracking individuals over large spatial scales. We used stable hydrogen isotopes in claw material to determine whether skylarks Alauda arvensis from a single breeding population in the Netherlands had migrated or remained resident in the previous winter and investigated whether there were causes or consequences of either strategy. Age and sex had no influence on the propensity to migrate, but larger individuals were more likely to be residents. The wintering strategy was not fixed within individuals. Up to 45% of individuals measured in multiple years switched strategies. Reproductive parameters were not related to the wintering strategy, but individuals that wintered locally experi-enced lower future return rates, and this was directly correlated with two independent measures of immune function. Our results suggest that partial migration in skylarks is based neither on genetic dimorphism nor on an age-and sex-dependent condition. Instead, the wintering strategy is related to structural size and immune function. These new insights on causes and consequences of partial migration advance our understanding of the ecology, evolution, and coexistence of different life-history strategies. [ABSTRACT FROM AUTHOR]

In this paper, an agent-based model of heterogeneous farmer decision-making was coupled with an individual-based model of skylark breeding populations, and applied to a small intensive arable catchment in Scotland. The impacts of farmer decisions on a tradeoff between food and bioenergy production, and skylark numbers, were simulated under the assumptions of three socio-economic scenarios until the year 2050. Bioenergy and food production had a significant negative effect on adult and fledgling skylarks. In a business-as-usual context, the production of food and bioenergy increases smoothly, and the number of skylarks is more stable over time than in other scenarios. Food production was higher in an economic liberalisation scenario, due to intensive management and higher yield performance. This explained the low average number of skylarks found at the landscape level in this scenario. The number of skylarks was highest in a sustainability-oriented scenario, but a sharp decrease was observed from 2035 onwards due to the large area planted with bioenergy crops. The different values for economic, environmental and social attributes of farmer decisions played an important role in the land use mosaic, the implementation of ecologically-related actions and on the provision of ecosystem services and biodiversity. Overall, results suggest that a re-assessment of policy targets and design is necessary to maximise environmental management efficiency at the catchment level by taking into account the heterogeneity in farmer objectives and the tradeoffs in ecosystem services provision. The novel approach of coupling an ABM with an IBM is encouraged in further land use related studies. [ABSTRACT FROM AUTHOR]

Animals gain benefits from group living through increased probability of predator detection, dilution of individual risk and confusion of predators during attack. A further benefit involves larger groups in which individuals may further decrease the amount of time spent being vigilant, while maintaining the probability of predator detection by allocation of this extra time to foraging activities. Living in groups or flocks, however, also incurs costs, e.g., by increasing inter-group competition, with negative impacts on intake rates. Our aim was to investigate the trade-offs between the costs of competition and the benefits of group living in contrasted habitats. For prey species that rely on sight for detecting predators, vegetation structure may influence the perceived predation risk. Hence, we experimentally examined the combined effects of vegetation height and inter-individual distance on foraging time, intake rate and foraging efficiency in a granivorous species, the Eurasian Skylark ( Alauda arvensis). Our experimental results based on temporally captive birds indicate that time devoted to foraging decreased with increasing inter-individual distance, but was unrelated to cover height. Conversely, increasing both vegetation height and distance with other group members did translate into a foraging disadvantage, i.e. reduced intake rate as well as foraging efficiency. Overall, our results show that both vegetation structure and inter-individual distances modify patch profitability, and therefore provide another example of how flock dynamics can influence the trade-off between vigilance and foraging. [ABSTRACT FROM AUTHOR]

Field margin management is a common measure employed in Europe to support farmland bird populations. In this study we found and analysed 237 nests of the Skylark Alauda arvensis in the Netherlands over a period of 6 years to determine the effects of arable field margins and breeding crop on nest-level reproductive success. Additionally, the effect of field margins on predation was investigated and food availability in crops and field margins was compared. Neither clutch size, nest survival nor nestling body weight were improved by field margin availability, irrespective of the breeding crop used. However, the choice of breeding crop had important effects. Nestling weight was significantly lower in cereals than in grassland and lucerne, corresponding with the low prey densities present in cereals. Nest survival was lowest in grassland due to frequent silage cutting. Predation rates were highest in cereals but were not affected by field margin proximity. The highest reproductive success was achieved in lucerne, which was mown twice a year and retained a suitable height for breeding throughout the breeding season. We conclude that field margins are not sufficient to maintain a Skylark population in this intensively farmed area. The presumably more subtle effects of increased food availability cannot compensate for the high nest failure rates resulting from agricultural operations and predation. In this and similar areas, the provisioning of safe nesting habitat throughout the breeding season is essential to improve breeding performance. Our research suggests that this can be achieved by reducing the frequency of silage cutting on grassland and by increasing the surface area of lucerne. [ABSTRACT FROM AUTHOR]

The autumn migration of SkylarksAlauda arvensisalong the southern Tyrrhenian coast of Italy from 1998 until 2014 is described, with respect to timing and phenology, sex-specific migration patterns and population trends. In total, 21,610 fully grown birds were captured and ringed, using mist nets, from October to mid November. The frequency distribution of wing length shows a clear bimodality due to sexual dimorphism, with males having longer wings than females. Wing length was used to determine sex in 20,622 individuals using Harding–Cassie plots: 57.1% were identified as females, 38.3% as males and 4.6% were undetermined. Autumn migration of Skylarks peaked during the second and third 10-day periods of October. Females migrated earlier than males: the median date of migration, based on combined data for all years, was 19 October for females and 25 October for males. The main migration period, expressed as the interquartile range, fell between 12 and 26 October for females and between 17 and 29 October for males. Based on capture numbers, we infer a fairly stable population migrating through the Volturno Plain, but with significant year-to-year fluctuations. [ABSTRACT FROM PUBLISHER]

The authors examine the influence of landscape and field-level agricultural management on wintering bird species in an unirrigated cereal farmland in central Spain. The number of assemblages of skylark Alauda arvensis, meadow pipit Anthus pratensis and corn bunting Emberiza calandra are high in plots with natural vegetation patches or with high-yield crops. Skylark tend to occupy arable land. Species richness is linked with landscape than field-level agricultural management.

Assessing the diet of farmland birds during the wintering period has important implications for conservation. However, for some species such as the skylark, the diet composition remains poorly known across its wintering range. On the basis of gizzards collected in mid-winter over a 10-year interval and in two regions of Western France, we quantified the contribution of seeds and investigated whether the diet differed between sexes, regions and period and whether seeds entered the diet with respect to their size, nutritive value or their spring occurrence within the farmland landscape. Also, the amount of seeds that birds need to consume for meeting their daily energy requirements was assessed by simulation and compared with estimates measured in captive individuals. Thirty-eight seed species belonging to 16 families were identified in gizzards. All species but one were weeds, and cereal grains were absent from all gizzards. The diet differed slightly between sexes but contrasted between regions and periods. We found no clear evidence for a selective intake based on seed traits. Conversely, our results suggest that weed seeds would enter the diet with respect to their relative occurrence. Our simulation indicated that birds should ingest about 8 g (4200-5600 seeds) to meet their daily requirements. A mean value of 6.7 g per day was measured in captive skylarks. These results suggest that the maintenance of rich weed habitats is a crucial issue for populations of skylarks that overwinter in agricultural landscapes of Western France. [ABSTRACT FROM AUTHOR]

The trade-off between forage quality and quantity has been particularly studied in herbivore organisms, but much less for seed eating animals, in particular seed-eating birds which constitute the bulk of wintering passerines in European farmlands. The skylark is one of the commonest farmland birds in winter, mainly feeding on seeds. We focus on weed seeds for conservation and management purposes. Weed seeds form the bulk of the diet of skylarks during winter period, and although this is still a matter for discussion, weed seed predation by granivorous has been suggested as an alternative to herbicides used to regulate weed populations in arable crops. Our objectives were to identify whether weed seed traits govern foraging decisions of skylarks, and to characterize key seed traits with respect to size, which is related to searching and handling time, and lipid content, which is essential for migratory birds. We combined a single-offer experiment and a multiple-offer one to test for feeding preferences of the birds by estimating seed intake on weed seed species differing in their seed size and seed lipid content. Our results showed (1) a selective preference for smaller seeds above a threshold of seed size or seed size difference in the pair and, (2) a significant effect of seed lipid biomass suggesting a trade-off between foraging for smaller seeds and selecting seeds rich in lipids. Skylarks foraging decision thus seems to be mainly based on seed size, that is presumably a ‘proxy’ for weed seed energy content. However, there are clearly many possible combinations of morphological and physiological traits that must play crucial role in the plant–bird interaction such as toxic compound or seed coat. [ABSTRACT FROM AUTHOR]

Background Vocal performance refers to the ability to produce vocal signals close to physical limits. Such motor skills can be used by conspecifics to assess a signaller's competitive potential. For example it is difficult for birds to produce repeated syllables both rapidly and with a broad frequency bandwidth. Deviation from an upper-bound regression of frequency bandwidth on trill rate has been widely used to assess vocal performance. This approach is, however, only applicable to simple trilled songs, and even then may be affected by differences in syllable complexity. Results Using skylarks (Alauda arvensis) as a birdsong model with a very complex song structure, we detected another performance trade-off: minimum gap duration between syllables was longer when the frequency ratio between the end of one syllable and the start of the next syllable (inter-syllable frequency shift) was large. This allowed us to apply a novel measure of vocal performance - vocal gap deviation: the deviation from a lower-bound regression of gap duration on inter-syllable frequency shift. We show that skylarks increase vocal performance in an aggressive context suggesting that this trait might serve as a signal for competitive potential. Conclusions We suggest using vocal gap deviation in future studies to assess vocal performance in songbird species with complex structure. [ABSTRACT FROM AUTHOR]

For the past 20 years, different policy and regulatory tools such as the agri-environment schemes ( AES) and the Natura 2000 network have been used in Europe to halt the ongoing decline of farmland birds resulting from agricultural intensification. Despite their wide implementation, bird populations are still declining at national and European scales, thus questioning the effectiveness of these schemes. Here, we examined the impact of the designation in 2004 of a Special Protection Area ( SPA) for the little bustard on the local trends of two non-targeted, common but declining farmland birds, the skylark and the corn bunting, in an intensive arable landscape of western France. From 1996 to 2012, trends in skylark presence or abundance decreased whereas trends in corn bunting abundance first decreased and then showed a recovery; the trends differed between outside and inside the SPA. Outside the SPA and consistently with trends at the national and European scales, skylark abundance sharply decreased whereas corn bunting abundance first decreased and then stabilized or even slightly increased. Within the SPA, the skylark declined less, and the corn bunting abundance increased at a faster rate than outside. Our results suggest that the implementation of a SPA in this arable landscape had a positive impact on these two farmland passerines, at least for corn buntings, for which the implementation of AES clearly improved habitat. Our results also suggest that the extensive implementation of SPAs may have had a positive impact on bird population trends in farmlands at a regional level, where c. 150 000 ha (15-20% of total arable landscape) have been designated since 2004. However, the SPA network (within Natura 2000) currently covers a mere 3.7% of French arable landscape, and it is therefore no surprise that specialist birds in farmland are still declining nationally. [ABSTRACT FROM AUTHOR]

The subject of biological invasion is now accepted as a major theme in environmental history. This paper analyses the role of human agency in the deliberately managed invasion of British birds to New Zealand in the late nineteenth century, and finds both historical and ecological relevance in the available data. Evidence concerning these introductions, largely undertaken by acclimatisation societies, has already played a significant role in the development of biological invasion theory. Analysis of some of the data has been used by ecologists to confirm the importance of propagule pressure (introduction effort) in successful introduction. This paper exploits the recently increased accessibility of historic newspaper references to acclimatisation in New Zealand and stresses their importance. Firstly, they show the limits of the database used until now by ecologists when analysing the introductions. Secondly, a close case study sheds new light on the full potential for human agency with regard to introduction effort. The historic role of skilled individuals in perfecting and passing on management techniques, increasing acclimatisation success, is explored. Attention is also given to secondary, and even tertiary, releases of exotic birds from locally-established populations within New Zealand, accelerating the rate of spread. This indicates more active, multi-layered human involvement than that identified by ecologists in their numerical analyses. Finally, it is suggested that examination of historic New Zealand avian introductions may have relevance for present-day conservation biology, given the parallel between small exotic populations seeking to establish in a new location and small populations of endangered native species trying to avoid extinction. By 1900 there may already have been a transfer of technical expertise, gained from acclimatising exotics, to the newer task of conserving the indigenous. [ABSTRACT FROM AUTHOR]

In recent decades, Skylark ( Alauda arvensis) populations in Europe have declined sharply due to agricultural intensification. Insufficient reproduction rates are one reason. Increased winter mortality may also be important, but studies outside the breeding season are scarce and mostly limited to the UK. We studied habitat selection of wintering Skylarks in an agricultural area in the Netherlands. We monitored Skylarks between November 2008 and March 2009 on 10 survey plots including 77 different arable fields and permanent grasslands and covering in total 480 ha. We simultaneously measured food availability, vegetation structure and field boundary characteristics. We also analysed 158 faecal pellets collected on potato and cereal stubble fields to relate Skylark diet to seasonal changes in food availability and foraging habitat. We show that cereal stubble fields larger than 4.3 ha, surrounded by no or low boundary vegetation and a density of dietary seeds of more than 860 seeds m, were most suitable for wintering Skylarks. Skylark group densities were low on permanent grasslands and on maize stubble fields. Densities of dietary seeds were highest in soils of potato stubble fields followed by cereal stubble fields, grasslands and maize stubble fields. Skylarks showed a strong preference for cereal grains, but their proportion in the diet fell sharply at the end of November, indicating that cereal grains were depleted and birds had to switch to less profitable food sources, such as weed seeds and leaves. We conclude that Skylarks wintering in agricultural landscapes possibly suffer from a lack of energy-rich food sources and only a few fields provide sufficient food. Conservation measures should strive to improve the wintering situation by creating food-rich habitats such as over-winter stubble with a rich layer of weeds on large fields and localised in open areas. [ABSTRACT FROM AUTHOR]

In songbirds of the temperate zone, often only males sing and their songs serve to attract females and to deter territorial rivals. In many species, males vary certain aspects of their singing behavior when engaged in territorial interactions. Such variation may be an honest signal of the traits of the signaler, such as fighting strength, condition, or aggressive motivation, and may be used by receivers in decisions on whether to retreat or to escalate a fight. This has been studied intensively in species that sing discontinuously, in which songs are alternating with silent pauses. We studied contextual variation in the song of skylarks ( Alauda arvensis), a songbird with a large vocal repertoire and a continuous and versatile singing style. We exposed subjects to simulated territorial intrusions by broadcasting conspecific song and recorded their vocal responses. We found that males sing differently if they are singing spontaneously with no other conspecific around than if they are territorially challenged. In this last case, males produced lower-frequency syllables. Furthermore, they increased the sound density of their song: they increased the proportion of sound within song. They seem to do so by singing different elements of their repertoire when singing reactively. Furthermore, they increased the consistency of mean peak frequency: they repeated syllable types with less variability when singing reactively. Such contextual variation suggests that skylarks might use low frequencies, sound density, and song consistency to indicate their competitive potential, and thus, those song features might be important for mutual assessment of competitive abilities. [ABSTRACT FROM AUTHOR]

Highlights: [•] We estimate effects of grass buffer strips on in-field biodiversity. [•] Buffer strip fields support more beetles and spiders compared to control fields. [•] Buffer strip fields also support more skylarks irrespective of sowing regime. [•] Buffer strip effects are expected to depend on landscape scale implementation. [ABSTRACT FROM AUTHOR]

Parallels between birdsong and human language are numerous and include particular temporal arrangements of acoustic units and the existence of dialects. In animal communication, modifications of the temporal ordering of existing acoustic units have rarely been clearly linked with changes in information content, particularly in a natural environment. Here, we show that the organization of birdsong units (‘syllables’) in sequences supports interindividual relationships within skylark communities. We manipulated the temporal arrangement of song dialect variants (‘shared phrases’) in the skylark, Alauda arvensis, a songbird with a very large repertoire of syllables and complex song. When tested with playback experiments performed in the field, skylarks were able to perceive subtle differences in the ordering of syllables. Modifications of the syllable ordering within shared phrases changed the information content from ‘group member’ to ‘unfamiliar individual’ and induced more aggressive reactions than shared phrases with a preserved syllable arrangement. Shared phrases often varied between individuals in the number of successive repetitions of similar syllable types, but were very consistent in terms of syllable type ordering. Our results indicate that skylarks rely not simply on the composition in syllable types of shared phrases to recognize group members, but on syllable type ordering. Shared phrases could be perceived by birds as ‘auditory objects’ embedded within songs. Alternatively, birds might identify incorrect phrases using grammatical rules governing the succession of syllables composing the phrases shared by their group. The presence of between-individual variation in phrase length, associated with consistent syllable type ordering revealed by our analysis, suggests that the latter hypothesis is more likely. Our results show that birds perceive disruptions in the natural temporal pattern of song units, and that this temporal pattern is behaviourally salient and carries information. [Copyright &y& Elsevier]

Highlights: [•] Skylark breeding habitat selection changes with spatial scale and time. [•] Skylarks select for areas of higher crop diversity up to a 200m scale around them. [•] Positive selection for crop diversity results from synergies among crops. [•] At landscape scale, smaller fields and crop well mixed are beneficial for Skylarks. [•] We must consider time, spatial scales and synergies in habitat selection studies. [Copyright &y& Elsevier]