Miliaria Calandra Research Articles

СОВРЕМЕННОЕ РАСПРОСТРАНЕНИЕ И ОЦЕНКА ОБИЛИЯ СТЕПНОГО ЖАВОРОНКА (MELANOCORYPHA CALANDRA) И ПРОСЯНКИ (MILIARIA CALANDRA) (PASSERIFORMES, AVES) НА СЕВЕРЕ НИЖНЕГО ПОВОЛЖЬЯ И СОПРЕДЕЛЬНЫХ ТЕРРИТОРИЯХ

СОВРЕМЕННОЕ РАСПРОСТРАНЕНИЕ И ОЦЕНКА ОБИЛИЯ СТЕПНОГО ЖАВОРОНКА (MELANOCORYPHA CALANDRA) И ПРОСЯНКИ (MILIARIA CALANDRA) (PASSERIFORMES, AVES) НА СЕВЕРЕ НИЖНЕГО ПОВОЛЖЬЯ И СОПРЕДЕЛЬНЫХ ТЕРРИТОРИЯХ

How to sustain meadow passerine populations in Europe through alternative mowing management

Two decades of agri-environmental policy did not prevent a long term decline of grassland birds in Europe. Additional measures are therefore needed to sustain the populations. This study explored alternative mowing management regimes likely to secure demographic sources in the early mown grassland systems of western Europe, and to limit habitat loss after farming abandonment in countries of the former Eastern Bloc. Postponing grass cutting until after mid-July from 2009 to 2014 in half of the area of 4 study sites (29–55ha each) in the Saône Valley (France), led to increased territory density and improved hatching success. Bird response however was species-specific: Corn Bunting Emberiza calandra territory density benefited the most from the alternative management, Yellow Wagtail Motacilla flava territory distribution tended to match the late mown areas, whereas the Whinchat Saxicola rubetra did not change its initial distribution. Temporary interruption of mowing in 8 meadow units (11.7–15.1ha) of the Moskva Valley (Central Russia) was similarly correlated with higher territory density. Whinchat territory density decreased after one single year of mowing. After two consecutive years of mowing, Whinchat hatching success was lower and the Lesser Citrine Wagtail Motacilla citreola werae virtually disappeared. The tested alternative mowing regimes may therefore locally increase population density without negative density dependent effects on hatching rates. Implementing rotational mowing could reduce habitat loss caused by farming abandonment in Russia. Postponing mowing until after mid-July in patches of hay fields may sustain meadow bird demography in the remaining strongholds of western Europe.

Crop sward structure explains seasonal variation in nest site selection and informs agri-environment scheme design for a species of high conservation concern: the Corn Bunting Emberiza calandra

Capsule Corn Buntings nested in tall dense grasses and cereals, selecting for sward density over height, and cereal fields with high weed scores.Aims To measure the vegetation attributes of fields selected as nest sites by Corn Buntings, to inform the design of safe nesting habitat measures in agri-environment schemes for this rapidly declining ground-nesting passerine.Methods Nesting activity was monitored across 32 farms in eastern Scotland during 2004–09. Land use and singing males were mapped to measure habitat availability for nesting females within their mate's territory, and crop swards measured. Effects of sward characteristics on field selection for nesting, and seasonal variation in crop use, were modelled.Results Nests (95% of 580) were mainly in cereals and grasses. Taller denser swards were selected, with sward density a stronger predictor of field use than sward height, and cereal field use strongly associated with high weed scores. Variation in sward structure between crop types, and changes due to crop maturation or harvesting, largely explained seasonal patterns in crop use.Conclusion Conservation measures targeting nesting Corn Buntings should provide uncut or late-cut grasses or cereals 30–100 cm tall with a dense ground layer of weeds or crop vegetation.

Habitat Preferences of Male Corn BuntingsEmberiza calandrain North-Eastern Germany

Agricultural ecosystems have faced dramatic changes during past decades, resulting in a dramatic loss of farmland biodiversity. The Corn Bunting Emberiza calandra is considered a suitable indicator for the conservation value of farmland habitats, and has recently suffered strong declines throughout much of its European range. As a basis for targeted conservation measures, we investigated the habitat preferences of this species in north-eastern Germany by comparing the composition of male territories with randomly chosen control sites. A territory was defined as the area within a radius of 150 meters around the assumed centre of the territory, as the majority of nests is found within this radius. To assess food availability for nestlings, arthropod abundance within the most abundant land use types i.e. crop fields, fallows, grassland as well as within unploughed strips was investigated. In total we found 102 male Corn Bunting territories, which were mainly composed of crop fields (50%), grassland (28%), and fallows (12%). Territories compared with control sites were characterized by a lower proportion of crop fields, a higher proportion of fallows, more diverse land use types, more abundant field boundaries, unploughed strips, and tracks, and a higher availability of song posts. However, neither the number of larger (≥ 1 cm), smaller (< 1 cm) or all arthropods differed significantly among analysed land use types i.e. crop fields, fallows, grassland, unploughed strips. Our study confirms the significance of habitat heterogeneity and especially of sites with sparse vegetation (fallows > 10%) and song posts (> 70 m ‘linear song posts’ or > 1 solitary post per ha) for the habitat selection of male Corn Buntings. We conclude that measures to halt population declines of Corn Buntings seem to be relatively easy to implement, provided that farmers are granted a fair compensation.

Influence of Landscape and Field-Level Agricultural Management on a Mediterranean Farmland Winter Bird Community

We studied the response to agricultural management factors of birds wintering in an unirrigated cereal farmland area of central Spain, examining the influence on species richness, abundance and community composition of different field-level and landscape-level agricultural management variables related to intensification. Our initial hypothesis was that landscape-level management factors exert a stronger effect on wintering bird species richness, total abundance and community composition than field-level ones. The particular responses of the most frequent species (skylark Alauda arvensis, corn bunting Emberiza calandra and meadow pipit Anthus pratensis) were also examined. Richer assemblages were found in more substrate-diverse plots with natural vegetation patches or in plots with higher yield crops, while the more abundant ones, dominated by the skylark, occupied more homogeneous areas dominated by cereals and arable land. As expected, landscape-level management factors explained a much greater proportion of variance in community composition compared to field-level factors (71% vs 29%, respectively). Species richness per se was favoured by substratediverse plots containing patches of natural vegetation, but also by plots where cereal crops were more productive in the previous harvest, declining in more homogeneous plots dominated by cereal crops and arable land in general. Conversely, skylark abundance and total abundance increased as landscapes became more homogeneous and dominated by cereals and arable land, although the relationship for total abundance only approached significance. Results suggest that the current landscape structure and levels of agricultural production of cereal farmland in central Spain can host relatively abundant winter populations of seed-eating and open landscape specialists like the skylark, although certain levels of habitat diversity need to be guaranteed to ensure the maintenance of rich wintering bird communities.

Influence of agri-environment scheme options on territory settlement by Yellowhammer (Emberiza citronella) and Corn Bunting (Emberiza calandra)

Conserving farmland birds is a key objective for agri-environment schemes (AES) across Europe, with a number of management options aimed at providing invertebrate food and nesting habitats. We analysed territory settlement by two widespread but declining farmland buntings with contrasting nesting requirements: the Yellowhammer Emberiza citrinella, a boundary-nesting species, and the Corn Bunting Emberiza calandra, a ground-nesting species. The study was conducted on farms participating in the English Higher Level Stewardship scheme to test whether territory settlement is influenced by the provision of key arable AES options. Both species settled preferentially in localities containing sown arable field margins, while Corn Bunting also settled in localities containing nectar flower mixtures. These preferences are likely to reflect foraging rather than nesting habitat requirements. Yellowhammer selected territories containing hedgerows under AES management, which are nesting rather than foraging habitat but may also provide food. Uptake by land owners of several AES options likely to provide limiting resources for farmland birds was very low, and because uptake at the landscape scale is also low, wider-scale population level benefits are likely to be constrained. However, this is one of few studies demonstrating selection of widely applied arable AES options by breeding farmland birds.

Habitat Preferences and Spatial Overlap Between Three Species of Bunting (Emberiza hortulana, emberiza cirlus, miliaria calandra) in Farmlands of Central Italy

Buntings species are mainly associated to agricultural landscapes and constitute a high conservation concern because farmlands are ecosystems subject to rapid changes and may cause the loss of animal species in just a few years. We studied the occurrence of Ortolan Bunting, Cirl Bunting and Corn Bunting (Emberiza hortulana, Emberiza cirlus, Miliaria calandra) on farmlands of Central Italy, considering the landuse composition, crop typologies and several structural parameters of environment occupied by these species, as presence of power lines, road type and Shannon biodiversity index of landscape. Furthermore the geographical overlap among the three bunting species was studied, in order to find witch species show an habitat overlap. The study was carried out in central-eastern Italy, between the end of April and mid-July 2010, through 159 sampled sites, uniformly distributed on in the study area. Cirl Bunting is the most widespread species of Bunting in the farmlands that were studied. Ortolan Bunting and Corn Bunting are the two species with greater spatial habitat overlap, even though land-use composition in their territories was different. However, Ortolan Bunting can be found at a lower altitude range than Corn Bunting (less 550 m a.s.l.) and it is associated to territories with minor landscape heterogeneity. Preferences by crop types seem to be a possible cause of the spatial habitat overlap between Ortolan and Corn Bunting (both species had selected sugar beet, and coriander, avoiding mainly vegetables, vineyards and orchards). On the other hand, Cirl Bunting was less related to crop types.

Are buntings good indicators of agricultural intensity?

Numerous countries in Western Europe have experienced a dramatic decline in their yellowhammer (Emberiza citrinella), corn bunting (E. calandra) and ortolan bunting (E. hortulana) populations. Data from the Common Breeding Bird Survey in Poland were used to examine the response of bunting population densities to agricultural intensification at different spatial scales. The results suggested that buntings preferred habitats that differed from those that are characteristic of Western Europe. Although yellowhammers preferred extensive agricultural areas, corn and ortolan buntings reached maximum densities in intensively managed farmland. In addition, both species preferred different woodlot structures and crop types. All studied bunting species exhibited non-linear responses to agricultural intensification. Under certain conditions, agricultural intensification may increase bunting population densities (especially for corn buntings). More generally, we provided a description of how complex patterns of bunting occurrence in agricultural landscapes may serve as indices of agricultural intensification in Europe.

Associations between species can influence the goodness of fit of species distribution models: The case of two passerine birds

Species distribution models (SDMs) are numerical tools that combine observations of species presence or abundance with environmental data, in order to develop predictive estimates about species distribution. The main variables used as regressors on SDMs are environmental parameters (climate variables, land-uses typologies, landscape metrics, etc.). However, there are several aspects that can affect the goodness of fit of species distribution models. For example, species traits, presence of associated species and anti-predator behaviors may cause differential responses to the processes that control their distribution. Considering these kinds of factors should improve the performance of models.In this work, SDMs were performed for two bird species found associated during initial exploration of data, by mean of a correlation matrix among bird occurrence. Models were performed first on environmental variables and then on environmental variables plus the occurrence of associated species. The goodness of fit of SDMs was compared using the area under the curve (AUC) and the likelihood ratio test.Our results showed how the associations between bird species can affect the goodness of fit of species distribution models. Specifically, we documented a significant increase in the AUC of the best model for red-backed shrike when adding the occurrence of corn bunting as a predictor. Our findings suggest how species-specific models in applied ecology can be developed to improve the predictive power of SDMs.

Species ecology and the impacts of bioenergy crops: an assessment approach with four example farmland bird species

AbstractThe cultivation of energy crops can cause land‐use conflicts, including loss of biodiversity in farmlands. In our study, we focus on farmland birds and analyse whether the impacts of such bioenergy activities differ for bird species with different ecology. We do this by comparing the impacts on four example species; skylark (Alauda arvensis), yellow wagtail (Motacilla flava), corn bunting (Miliaria calandra) and northern lapwing (Vanellus vanellus). We used a spatially explicit ecological model, which combines three simplified crop selection criteria (suitability for nesting, suitability for foraging, spatial heterogeneity) that differ between the selected species. We used the model to investigate change in breeding pair density between a baseline and several bioenergy scenarios that differ in intensity and spatial agglomeration. We subsequently simulated scenarios with potential positive habitat effects (maintenance of 10% set‐aside or 10% alfalfa) as well as spatial effects (increased crop diversity and reduction of field size) as mitigation strategies to increase the breeding pair density. The four species responded to the bioenergy scenarios with a decrease in breeding pair density that can be divided into roughly three levels: strong (skylark), intermediate (yellow wagtail and corn bunting) and no response (northern lapwing). The intensity of the response depended on the bioenergy scenario. The decrease in breeding pair density under the least intensive bioenergy scenario could be fully mitigated for all the considered bird species through 10% set‐aside. However, with increasing dominance or spatial agglomeration of a single energy crop (e.g., maize), impacts cannot or hardly be mitigated and the effectiveness of the mitigation strategies becomes increasingly more dependent on the ecological preferences of the bird species.

Focal species of birds in European crops for higher tier pesticide risk assessment

Focal species have been defined by the European Food Safety Authority (EFSA) as real species that represent others in a crop resulting from their potential higher level of exposure to pesticides. As such they are the most appropriate species for refining estimates of exposure further, through, for example, radio tracking and dietary studies. Plant protection product manufacturers collectively commissioned many studies in Europe, according to the EFSA guidelines, to identify focal species in different crops that may be used in risk assessments for spray applications of pesticides. Using frequency of occurrence in crops and risk-based criteria for exposure, all studies have been reviewed to identify if possible at least 1 focal species per feeding guild, per crop in the new registration zones for southern and central Europe. Some focal species repeatedly appeared across a wide range of arable or tree crops but not both, demonstrating broad adaptation to these 2 different crop structures. Many have widespread distributions, for example, 15 of the focal species have a distribution covering all agricultural regions of Europe (northern, central, and southern zones). Three species, corn bunting, serin, and tree sparrow, are restricted to the central and southern zones, whereas another 4 species, Sardinian and fan-tailed warbler, and crested and short-toed lark, are essentially restricted to the southern zone. The authors consider the focal species identified as suitable for risk assessment in Europe at the zonal level and for further refinement of exposure through studies, such as radio tracking or diet analysis, if necessary.

Identification of habitat requirements of farmland birds based on a hierarchical structured monitoring scheme

Agricultural landscapes are essential for the conservation of biodiversity. Nevertheless, a negative trend continues to be observed in many rural areas for the most prominent indicator species group, the farmland birds. However, clear cause-effect relationships are rarely reported and sometimes difficult to deduce, especially from monitoring data which are based only on the detection of species and counts of the numbers of individuals. Because the identification of habitat preferences is a precondition for farmland bird biodiversity conservation efforts, a monitoring scheme for the simultaneous collection and analysis of bird and land use data was developed and tested. In order to assign the occurrence of bird species to land characteristics at various spatial scales and different land use and crop types, we applied a hierarchical structured sampling design. The spatial scales were ‘agricultural landscape’, ‘agricultural landscapes types’, ‘field crops and other habitats’ and ‘vegetation structures’. These scales were integrated with a novel concept, the ‘habitat matrix’ (HM). This method was applied to farmland breeding bird abundances on 29 plots, each 1 km² in size, by the use of the territory mapping method. The same plots were enlarged by a 100 m buffer and the sizes and location of habitats documented. Vegetation height, coverage and density was also recorded for all crop fields in the study area. We propose that this monitoring method facilitates the identification of scale dependent relationships between farmland bird habitat characteristics and bird abundance. This is demonstrated by the farmland bird species Corn Bunting (Emberiza calandra), Skylark (Alauda arvensis), and Whinchat (Saxicola rubetra). The breeding territories of these species reveal large differences within the various spatial scales ‘agricultural landscape’, ‘agricultural landscape types’ and ‘field crops’. Throughout the breeding season the abundances varied, dependent on the field crop and the development of vegetation structures (height, coverage, and density). HM-analysis led to the identification of specific habitat configurations preferred by individual bird species within the agricultural landscape. These findings indicate that the methodology has the potential to design monitoring schemes for the identification of cause-and-effects of landscape configuration, land use and land use changes on the habitat suitability and abundance of farmland birds.

Local improvement of skylark and corn bunting population trends on intensive arable landscape: a case study of the conservation toolNatura 2000

AbstractFor the past 20 years, different policy and regulatory tools such as the agri‐environment schemes (AES) and theNatura 2000 network have been used inEurope to halt the ongoing decline of farmland birds resulting from agricultural intensification. Despite their wide implementation, bird populations are still declining at national andEuropean scales, thus questioning the effectiveness of these schemes. Here, we examined the impact of the designation in 2004 of aSpecialProtectionArea (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 westernFrance. 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 theSPA. Outside theSPAand consistently with trends at the national andEuropean scales, skylark abundance sharply decreased whereas corn bunting abundance first decreased and then stabilized or even slightly increased. Within theSPA, the skylark declined less, and the corn bunting abundance increased at a faster rate than outside. Our results suggest that the implementation of aSPAin this arable landscape had a positive impact on these two farmland passerines, at least for corn buntings, for which the implementation ofAESclearly improved habitat. Our results also suggest that the extensive implementation ofSPAsmay have had a positive impact on bird population trends in farmlands at a regional level, wherec. 150 000 ha (15–20% of total arable landscape) have been designated since 2004. However, theSPAnetwork (withinNatura 2000) currently covers a mere 3.7% ofFrench arable landscape, and it is therefore no surprise that specialist birds in farmland are still declining nationally.

Delayed mowing increases corn bunting Emberiza calandra nest success in an agri-environment scheme trial

Management intensification in agricultural grasslands is a major conservation concern. During the last 50 years, meadows have been drained, re-seeded with high-yielding grasses, treated with chemicals to remove pests and promote rapid growth, and mowing has become earlier and more frequent. This has severely reduced the reproductive success of several meadow-nesting bird species across large areas of Europe, causing population declines. Corn buntings Emberiza calandra have been excluded from nesting in meadows across much of north-western Europe by earlier mowing and tend to persist only in later-harvested cereal crops. However, in areas where meadow-nesting persists, adjustment of mowing dates supported by agri-environment schemes could still be a critical conservation measure for remaining populations. Using trial conservation interventions, we tested the relationship between delayed mowing and reproductive success across 19 mixed arable/grassland farms in the main remaining range of corn buntings in Scotland, over five breeding seasons. Corn buntings require around five weeks from nest building to fledging, and in Scotland start nesting during mid-May–June. Delayed mowing to 1 August (6–8 weeks after the mean first egg date of first nesting attempts in meadows) significantly increased the probability of a brood fledging (0.282, compared with 0.034 in fields mown in June or July), with a potential population-wide effect of raising overall breeding productivity across all crop types by 20%. To reach the level required for population stability (1 successful brood per female), we estimate that at least 40–50% of the nests in meadows must be in fields with delayed mowing. With effective targeting, this could be achieved by delayed mowing in just 10–20% of meadows (260–520ha throughout the species’ northeast Scotland range), at a cost of £100000–£160000 per year.

Integrating Open Access Geospatial Data to Map the Habitat Suitability of the Declining Corn Bunting (Miliaria calandra)

The efficacy of integrating open access geospatial data to produce habitat suitability maps for the corn bunting (Miliaria calandra) was investigated. Landsat Enhanced Thematic Mapper Plus (ETM+), Shuttle Radar Topography Mission (SRTM) and Corine (Coordination of Information on the Environment) land cover data for the year 2000 (CLC2000) were processed to extract explanatory variables and divided into three sets; Satellite (ETM+, SRTM), CLC2000 and Combined (CLC2000 + Satellite). Presence-absence data for M. calandra, collected during structured surveys for the Catalan Breeding Bird Atlas, were provided by the Catalan Ornithological Institute. The dataset was partitioned into an equal number of presence and absence points by dividing it into five groups, each composed of 88 randomly selected presence points to match the number of absences. A logistic regression model was then built for each group. Models were evaluated using area under the curve (AUC) of the receiver operating characteristic (ROC). Results of the five groups were averaged to produce mean Satellite, CLC2000 and Combined models. The mean AUC values were 0.69, 0.81 and 0.90 for the CLC2000, Satellite and the Combined model, respectively. The probability of M. calandra presence had the strongest positive correlation with land surface temperature, modified soil adjusted vegetation index, coefficient of variation for ETM+ band 5 and the fraction of non-irrigated arable land.

How to improve agri-environment schemes to achieve meadow bird conservation in Europe? A case study in the Saône valley, France

Ongoing meadow bird demographic trends in Europe raise the question of the effectiveness of public policy aiming to halt biodiversity loss. In this study, we attempted to understand the success and failures in one of the first French Agri-Environment Schemes (AES), 20 years after its implementation. After annually postponing grass harvesting to 1 or 15 July in 25 % of a 3,000-ha lowland meadow system, we observed a clear demographic increase in the Eurasian Curlew Numenius arquata, the Whinchat Saxicola rubetra and the Yellow Wagtail Motacilla flava. No positive effects were recorded for the Skylark Alauda arvensis, the Corn Bunting Miliaria calandra and the Reed Bunting Emberiza schoeniclus, possibly as a result of increased competition with Whinchats and Yellow Wagtails, and the Corncrake Crex crex declined sharply despite the implemented measures. The successful results were attributed, for the Curlew to the species’ early nesting and high adult survival, for the Whinchat to the probable support of immigration, and for the Yellow Wagtail to a possible capacity to avoid unfavourable nesting situations. Late breeding and low adult survival may contribute to explain the continuing Corncrake decline. In the study site, late mown AES areas were too small and fragmented to match efficiently the territory aggregations. We recommend to extend AES principles to all the European range of targeted species, even outside the EU, and to develop species-specific spatial strategies.

Habitat associations of wintering granivorous birds on the Canary Islands

Farmland birds within arable land are of conservation concern in Europe, but little is known about their ecology in the oceanic islands of the Mediterranean Basin (Macaronesia).We report here that, during two consecutive winters and within the entire arable land area of the Canary Islands, increasing area of bare soil is associated with higher occurrences of the resident granivorous species Corn Bunting (Emberiza calandra), Atlantic Canary (Serinus canaria) and Linnet (Carduelis cannabina meadowaldoi). However, such a relationship was not found for wintering Skylarks (Alauda arvensis) probably because of its different diet.We recommend that local authorities, theCabildo de Tenerife, purchase and manage these lands to improve conditions for granivorous farmland birds.We suggest that providing suitable foraging habitat will support the recovery of farmland birds on this island.

Conservation insights from changing associations between habitat, territory distribution and mating system of Corn Buntings Emberiza calandra over a 20‐year population decline

Associations between habitat and animal distributions are widely used to make conservation recommendations. However, short‐term studies do not allow investigation of temporal variation in associations as habitats change or populations decline. Here we quantify changes in the habitat attributes and distribution of breeding territories in a multiple‐brooded, crop‐nesting farmland bird, the Corn Bunting Emberiza calandra, over a 20‐year period during which the study population declined by 91%. Corn Buntings were positively associated with weedy fields, overhead wires, spring cereals and, in early summer, with winter barley and forage grass. Territory associations with wires (positive) and fallow (positive in early summer, negative in late summer) were stronger in later years when the population was smaller. Trends in the proportions of males holding territories into late summer (decline), and mated polygynously or not at all (increases), suggested that habitat quality declined and became more spatially variable in later years. Field size increased and weed abundance within fields declined, reducing the availability of field‐boundary song‐posts, invertebrate‐rich foraging habitats and physical cover for nests within crops. Conservation recommendations are for weed‐rich or under‐sown spring cereals and winter barley combined with late‐cut hay and fallow, especially when offered close to song‐posts such as overhead wires. We also demonstrate the value of long‐term studies by comparing our 20‐year analysis with 3‐year periods at the start, middle and end of this period, and expose some risks of conservation recommendations derived from short studies.

A spatially explicit assessment of within‐season changes in environmental suitability for farmland birds along an altitudinal gradient

AbstractThe intra‐seasonal adjustment in site selection, and hence in distribution of multi‐brooded avian species, is a poorly investigated topic of potentially high relevance for conservation. This phenomenon may be especially important among multi‐brooded species occurring in habitats undergoing large modifications. We used correlative species distribution models to carry out a spatially explicit assessment of variation in habitat suitability between early and late periods of the breeding season for four European farmland passerine species (woodlark Lullula arborea, skylark Alauda arvensis, cirl Emberiza cirlus and corn bunting E. calandra). We counted birds at transects (surveyed in early and late season) in Northern Apennines (Lombardy, Italy), and modelled their spatial distribution with MaxEnt, separately for early and late season periods. A comparison of predicted environmental suitability (ES) at occurrence sites showed significant differences between early and late period ES at both early and late occurrence sites. Three species showed differences in elevation between early and late occurrence sites. The proportion of 1‐ha cells predicted as potentially suitable during the entire breeding season ranged from 29.3% (corn bunting) to 52.8% (woodlark) of the at least once suitable cells. In multi‐brooded birds, a dynamic pattern of species occurrence may be likely and particularly important in farmland habitats along altitudinal gradients. The resulting within‐season switches in habitat and distribution could be widespread among farmland birds and could have critical implications for their conservation. Moreover, such habitat switches provide an additional reason for preserving habitat heterogeneity. The intra‐seasonal variation in habitat association/distribution should become a focal topic for researchers.

Protection strategies for farmland birds in legume–grass leys as trade-offs between nature conservation and farmers’ needs

The study shows organic legume–grass leys to be highly attractive for skylark (Alauda arvensis), corn bunting (Emberiza calandra), yellow wagtail (Motacilla flava) and whinchat (Saxicola rubreta). But due to harvesting three to four times per year, legume–grass leys can become an ‘ecological trap’. Therefore, the aim was to analyse the effects of optimized harvesting measures on territory densities and the breeding success of farmland birds and, concomitantly, on forage yield and quality of dairy farms: (1) later first cut, (2) later second cut, (3) high first cut and (4) unmown strips. Measures (1) and (2) improve productivity for breeding skylark but result in a sharp decline in the nutritional quality and net energy lactation yield (NEL) in the conserved forage. Measure (3) causes a yield reduction of about 5 GJ NEL ha−1 with no effect on quality. Due to the higher cut, grass regrowth is accelerated, and this could lead to earlier nest initiation for skylark, rendering a delay in the second cut unnecessary. Direct nest losses are reduced for all species. Measure (4) might allow whinchat and yellow wagtail to maintain territories after mowing and may increase the reproductive success of all species, with yield reductions similar to measure (3). For the first time, this study demonstrates, under large-scale practical conditions (1,200 ha), measurable benefits for farmland birds in legume–grass leys by integrating modified harvesting measures. The effectiveness and the feasibility are highly dependent on individual farm conditions; we therefore recommend the adoption of all measures into agri-environmental schemes.