Corn Bunting Emberiza Calandra Research Articles

Conservation potential of semi-natural habitats for birds in intensively-used agricultural landscapes

Agricultural intensification resulted in substantial loss of farmland biodiversity. Semi-natural habitats may be viewed as potential buffers of these adverse impacts, but a rigorous assessment of their capacity for supporting farmland biodiversity is lacking. In this study, we explored conservation potential of two different types of semi-natural habitats for birds in intensively-used agricultural landscapes – farmland hedges (i.e., linear strips of shrubby and tree vegetation) and open scrubland (i.e., scattered shrubs and abandoned orchards). Specifically, we tested whether the abundance and species richness of birds differ between these habitats considering various species traits, such as habitat affinity (i.e., forest, farmland and urban species), diet specialization (i.e., animal eaters, plant eaters, and omnivores) and conservation status (Species of European Conservation Concern). We found that open scrubland hosted on average 37.9 bird species and 122.6 individuals per 1 km2 of the transect, whereas farmland hedges hosted only 19 species and 61.8 individuals per 1 km2 of the transect. However, results have substantially changed if we considered the area of suitable habitat into account. More specifically, open scrubland hosted more bird species and individuals when we considered open habitat species and the area of open habitats, whereas farmland hedges had higher species diversity and individuals of woodland bird species when we considered the area of woodland habitats. Similarly, analyses of habitat affiliations of individual species corresponded to the whole-community patterns; and revealed that several woodland bird species were mainly associated with farmland hedges (e.g., Chaffinch Fringilla coelebs, Common Nightingale Luscinia megarhynchos and Blackcap Sylvia atricapilla), whereas the open scrubland was preferred by open habitat bird species (e.g., Corn Bunting Emberiza calandra, Quail Coturnix coturnix and Skylark Alauda arvensis). These results demonstrate that semi-natural habitats, both open scrubland and farmland hedges, have large potential for promotion and conservation of bird communities within intensively used agricultural landscapes, as both may have represented suitable habitats for species with different ecological requirements. Therefore, management measures focused on the enlargement of the area of these habitats, in combination with suitable management (e.g., regulating the progress of natural succession in open scrubland; increasing structural diversity of existing farmland hedges), may substantially contribute to bird conservation within agricultural landscapes.

Could Meadow Passerine Distribution Within a Grassland System be Influenced by Spatial Variation in the Mowing Schedule?

This study explored meadow passerine capacity to select habitat conditions likely to preserve their breeding success. We observed the variation in bird abundance, assessed with the point count method, over a 25-year period (1993–2017) within two phytosociological facies of the hay-meadows in the lower Saone Valley (3.000 ha), eastern France: a meso-hygrophilic facies characterized by increasingly early mowing, and a hygrophilic facies mown later, with thereby a lower risk of nesting failure. At the beginning of the monitoring (1993–2001), birds were evenly distributed within the two facies. Later on, as more than 90% of meso-hygrophilic meadows were already mown by July 1, birds became more abundant in the hygrophilic facies. This trend was observed in each of the two most abundant species, the Whinchat Saxicola rubetra and the Corn Bunting Emberiza calandra. In two hygrophilic areas (55 and 76 ha) and two meso-hygrophilic areas (49 and 116 ha), passerine territories were mapped in 2011 with the territory mapping method and invertebrates were captured weekly on transects with colour plates and Barber traps. In spite of substantially higher invertebrate abundance, passerine territory density was lower in meso-hygrophilic study sites (6.4 territories/ 10 ha vs. 10.6). Within each study site however, captured invertebrates were more abundant in the areas selected by territorial birds. In fact, bird abundance estimated from point counts in 2011 varied negatively with the percentage mown by July 1 within a 200m-radius in 2010. This apparently adaptive behaviour leading to a selection of later mown fields seemed to be successful since bird abundance increased until 2010. However, after a succession of extreme climatic events (droughts, late floods), passerine abundance declined thereafter in both facies.

The effects of forest succession and grazing intensity on bird diversity and the conservation value of a Northern Adriatic karstic landscape

We studied the effects of different land uses on conservation value and bird diversity in a Northern Adriatic karstic landscape. Our research area was situated in SW Slovenia and was covered with dry pastures and meadows in different stages of forest sucession and with different grazing intensities. We surveyed birds in 2007 and 2012 using the line transect method, with 50.4 km being covered each year. In the analysis we divided the survey transects into 200 m tiles which were used as statistical units in the analysis. We then modelled conservation value, bird diversity and bird abundances with different land uses; we used boosted regression trees as a modelling tool. Canonical correspondence analysis showed that a distinct group of birds occurred on tiles with higher grazing intensity. The species in this group also had significantly higher abundances in 2012 than in 2007. Forest succession was the most important predictor of SPA conservation value (Special Protected Areas according to the Directive on the conservation of wild birds of the European Union) and had negative effect on it; grazing intensity had a unimodal positive influence on conservation value and was most beneficial at low intensity. The model for the European conservation value showed a rather low predictive power. Farmland bird diversity was also negatively affected by forest and positively by grazing intensity. For the four Natura 2000 species—protected species in the SPA Kras (Woodlark Lullula arborea, Red-backed Shrike Lanius collurio, Corn Bunting Emberiza calandra and Skylark Alauda arvensis), forest cover also had a negative effect. Grazing intensity had a positive effect for Woodlark, Red-backed Shrike and Skylark. The highest SPA conservation value and farmland bird diversity could therefore be achieved in a landscape with as low a forest succession as possible and grazing present but at low intensity. We recommend inclusion of appropriate measures in the agri-environment schemes (CAP pillar II) of Rural Development Programmes of the countries in the region with similar areas. The payments should be sufficiently stimulative to reopen the large areas subject to forest encroachment in the Northern Adriatic hinterland.

On habitat characteristics driving meadow passerine densities in lowland hay-meadow systems in France

For meadow bird conservation in Europe, promoting specific farming models in their remaining strongholds could be a necessary complement to the ongoing agri-environmental policy. This study aims at understanding the main drivers of meadow passerine density in the objective of guiding conservation policies. The data were collected in 56 lowland hay-meadow regions important for grassland bird breeding in France. The objective was to explain, using GLMMs, the variation in meadow passerine density, measured annually in 490 12-ha plots during the period 2006–2010 by the count point method. Explanatory variables enabled us to describe farming management, sward structure and habitat size. Passerine density (all species except the skylark Alauda arvensis) depended on the extent of habitat available and on the percentage of meadow already mown on June 20. More specifically, the skylark was attracted to low, floristically rich and early mown swards, the whinchat Saxicola rubetra and the yellow wagtail Motacilla flava to large areas of favourable habitat, and the corn bunting Emberiza calandra to floristically rich meadows mown later than June 20. Extensive farming models based on late mowing in the largest habitat units should therefore be a target for meadow passerine conservation. The skylark was an exception. Because of its apparent tendency to use early mown grasslands, we recommend to rather invest on alternative habitats for sustaining the demography of this species.

The Proportion of Cropland Influences Negatively the Occurrence of Breeding Birds in an Alkali Grassland Habitat in NW Serbia

Abstract Grasslands host a high diversity of plant and animal species. In Serbia, most alkali grasslands are located in the province of Vojvodina. The majority are not subject to conservation. The aim of the study was to investigate the relationship between the proportion of croplands and (1) the number of breeding species and (2) the number of breeding pairs in the alkali grasslands of the upper Mostonga River catchment basin (NW Serbia). The size of the study area was 400 ha. Birds were surveyed along seven parallel transects eight times per breeding season. Lengths of the cross sections of both grasslands and croplands were measured. The proportion of croplands per transect was calculated by dividing the total length of cross sections of croplands by the total length of transect. The relationship between the proportion of croplands and the number of breeding pairs and the number of breeding species, respectively, was studied using simple linear regression. We recorded a total of 171 nesting pairs belonging to 23 species in the alkali grassland investigated, with breeding densities between 2.2 and 10.3 pairs per 10 ha. The number of species per transect ranged between 6 and 11. The most abundant species were Skylark Alauda arvensis, Yellow Wagtail Motacilla flava and Corn Bunting Emberiza calandra. The numbers of breeding pairs (F6 = 21.761, P < 0.0001) and of breeding species (F6 = 13.758, P = 0.001) were both influenced negatively by the proportion of croplands. These findings highlight the need for coordinated conservation measures on the alkali grasslands of Vojvodina.

The influence of crop tiller density on the breeding performance of a cereal‐nesting specialist

Summary In the pursuit of maximizing agricultural yields and profits, crop management under intensive agriculture has reduced the heterogeneity of crop sward structure within fields. Several farmland bird specialists that nest within arable crops have undergone marked population declines during recent periods of agricultural intensification. Understanding the mechanisms that link crop sward structure to demographic fitness and population change may be important for developing effective conservation solutions. We studied whole‐season breeding performance of a declining cereal crop specialist, the corn bunting Emberiza calandra, to test the relationships between crop sward structure and both nest site selection and reproductive output within intensively farmed landscapes. Experimental double‐drilling of cereal seed was used to manipulate crop sward structure and explain the observed within‐field nest distribution. The density of crop tillers (reproductive cereal stems) was a strong predictor of nest site selection and a disproportionate number of nests occurred close to (15–30 m) crop edges where regular seed sowing overlaps (operational double‐drilling) occurred during crop establishment. Nest survival was subject to a strong crop edge effect and re‐nesting rate increased with mean tiller density in the surrounding crop. Experimental double‐drilling that simulated seed sowing overlaps increased crop tiller density (by 25%) and corn bunting nest density (by 406%) compared to adjacent areas of operational double‐drilling. Corn buntings breeding in intensively managed cereal crops therefore place their nests in areas of high tiller density which under normal sowing practice tend to occur close to crop edges where nest survival is low. A simple population model indicated that productivity under conventional, intensive cereal management may be too low to sustain local populations in the absence of immigration. Modern cereal husbandry therefore creates an ecological trap for nesting corn buntings. Synthesis and applications. This study highlights a novel mechanism by which modern cereal crop management lowers the potential reproductive success of a conservation priority species nesting in intensively managed cereal crops. Unavoidable overlapping of cereal seed along crop headlands, close to crop edges, systematically produces patches of dense sward that attract nesting corn buntings. This creates an ecological trap because nests close to crop edges are subject to high predation rates, and this may be linked to the loss of arable weeds elsewhere within crops. When double‐drilled strips are intentionally provided adjacent to these areas, nesting preference switches to these strips, suggesting a potential conservation solution. Provision of mid‐field double‐drilled strips at least 100 m from crop edges, if similarly selected by nesting females, should raise nest survival rates and improve population trends. Such interventions are simple and cheap to implement, unlike most conservation measures in high‐value cropping systems.

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.

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.

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 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.

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.

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.

An agri‐environment option boosts productivity of Corn Buntings Emberiza calandra in the UK

The potential for agri‐environment schemes to reverse farmland bird declines is limited for some species by a lack of suitable prescriptions, in particular effective in‐field options for species that breed in crops. We assess the provision of alternative nesting habitat for increasing productivity of the Corn Bunting Emberiza calandra. Breeding success was monitored over three years in response to a tailored option that provided extensively managed crops of spring‐sown barley, most of which were funded by existing agri‐environment schemes and were left unharvested. Corn Buntings nested in both extensively managed crop provisions and conventional intensively managed barley crops. Females that used extensively managed crops for first nesting attempts were almost four times more likely to re‐nest, despite their later onset of breeding, than females nesting in conventional crops. The latter rarely produced a second nest and, when they did, usually switched nesting habitat. Extensively managed cereal crops were strongly selected by breeding females and supported a high proportion of the breeding population. A re‐nesting model demonstrated that differential re‐nesting rates led to 26% higher annual productivity per female in extensively managed cereal crops. Scenario testing illustrated the importance of timely establishment and deferred harvest of these extensively managed cereals. We recommend the provision of unharvested, extensively managed cereal crops as an agri‐environment option for Corn Buntings where intensively managed cereal crops are the main nesting habitat.

Ensuring applied ecology has impact

Ensuring applied ecology has impact E. J. Milner-Gulland*, Jos Barlow, Marc W. Cadotte, Philip E. Hulme, Gillian Kerby and Mark J. Whittingham Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, SL5 7PY, UK; Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK; Department of Biological Sciences, University of Toronto, Scarborough, ON, Canada; Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada; Bio-Protection Research Centre, PO Box 84, Lincoln University, Canterbury, New Zealand; British Ecological Society, Charles Darwin House, 12 Roger Street, London WC1N 2JU, UK; and School of Biology, Ridley Building, Newcastle University, Newcastle-Upon-Tyne, NE1 7RU, UK

Effects of landscape, conspecifics and heterospecifics on habitat selection by breeding farmland birds: the case of the Calandra Lark (Melanocorypha calandra) and Corn Bunting (Emberiza calandra)

The aim of habitat selection studies is to understand the effect of the different factors affecting the spatial distribution of individuals. Within this framework, the aim of this study was to evaluate the relative contributions of landscape features and conspecific and heterospecific interactions to habitat selection by two sympatric species, the Calandra Lark Melanocorypha calandra and the Corn Bunting Emberiza calandra, during the breeding season. During the 2008 breeding season, the population of both species was censused in three Central Spanish locations by means of transects (N = 58). A model-averaging approach was used to determine the weight and effect of landscape and interaction variables in each species’ habitat selection using abundance as the dependent variable. Deviance partitioning was used to determine the unique and shared contributions of these two sets of variables to the variation explained by the models. Calandra Lark was positively associated with mean field size, which reflects its preference for relatively simplified landscapes with a low density of field margins and, consequently, small land-use diversity. Corn Bunting selected areas with high land-use diversity, namely, a highly heterogeneous landscape with a high density of field margins. Attraction between conspecifics was found in both cases. Calandra Lark seems to negatively respond to the proximity of Corn Buntings, which indicates a partitioning of space and food resources. However, Corn Bunting responded positively to the proximity of Calandra Larks, which reflects a higher tolerance of Corn Buntings to the presence of other species nearby. Deviance partitioning showed that interactions were more important for Calandra Lark, while Corn Bunting was equally affected by both components. An appropriate management should combine the requirements of both species to achieve effective conservation at the bird assemblage level.

Adaptive management and targeting of agri-environment schemes does benefit biodiversity: a case study of the corn bunting Emberiza calandra

Summary 1. Agri-environment schemes (AES) are the main European policy response to biodiversity loss caused by agricultural intensification. Maximizing their effectiveness is a key policy challenge. Monitoring is essential to inform adaptation and improvement of schemes over time, and to understand how measures may need to vary across a species’ range. 2. We measured changes in breeding abundance of a severely declining bird, the corn bunting Emberiza calandra, in response to AES in Scotland over 7 years and 71 farms. Two AES were monitored, one with general management for farmland birds, and one with targeted, adaptive management for corn buntings. We use these data to estimate the proportion of the population that AES must influence to halt the overall decline. 3. Corn buntings increased by 5·6% per annum on farms in the targeted AES, showed no significant change on farms in the general AES, and declined by 14·5% per annum on farms outside AES. 4. In arable-dominated areas, AES management that increased food availability reversed population declines. However, where a high proportion of corn buntings nested in grasslands, an additional AES option that delayed mowing was essential to achieving population increase. 5. Results suggest that approximately 72% of the corn bunting population in mainland Scotland must receive targeted AES management to halt the current decline. In 2009, only 24% was targeted in this way. 6. Synthesis and applications. AES measures are capable of reversing corn bunting declines in Scotland, and the same measures are likely to benefit a wide range of other taxa too, but require geographical targeting and flexibility to adapt and improve management options, backed by expert advice. Targeted AES provision to the required level for corn buntings will cost approximately £120 000 per annum, with 500–600 ha under appropriate management. This is 0·02% of annual subsidies paid to Scottish farmers, and 0·5% of land in the remaining mainland range of the corn bunting. These outcomes illustrate the value of AES monitoring studies to assess scheme effectiveness, identify improvements, and determine the scale of implementation required for reversing species declines.

Assessing the impact of Entry Level Stewardship on lowland farmland birds in England

Agri‐environment schemes (AES) are central to the conservation of Europe’s farmland biodiversity. The UK Government’s Public Service Agreement target seeks to reverse the decline of farmland birds in England by 2020 through the use of AES. The Entry Level Stewardship (ELS) scheme, introduced in 2005, is the first non‐competitive, broad‐uptake stewardship scheme designed to deliver simple but effective environmental management on farms throughout England. Approximately 5 million hectares of farmland are currently entered into Environmental Stewardship (ES) agreements, and given the scale of this investment it is important to verify the efficacy of ELS as a mechanism for delivering biodiversity benefits. We used spatially referenced ES agreement data to assess the influence of specific management options and combinations of options on farmland bird population changes between 2005 and 2008 derived from standardized surveys carried out on over 2000 lowland farmland 1‐km squares in England. The results showed only limited evidence for short‐term effects of ES. Only Corn Bunting Emberiza calandra and Common Starling Sturnus vulgaris showed some landscape‐specific positive associations with area under ELS management. There was also limited evidence for positive associations between specific management options and the population changes of the species at which they were aimed. The current pattern of option uptake may be limiting benefits of ELS, with boundary management accounting for over 50% of scheme compensation value. However, the time required for option maturation and the time lags in bird population responses to environmental change mean that it is too early to reach definitive conclusions about the success or failure of the scheme. The findings of this study will assist in the development of ELS by feeding into the 5‐year review scheduled for 2010 and have implications for the development of similar schemes elsewhere in Europe.

Using repeated winter surveys to estimate changes in abundance of seed‐eating passerines

Capsule Winter Atlas surveys of 16 species on lowland farmland revealed significant changes in count for four species. Aims To estimate changes in abundance between the early 1980s and late 1990s, of wintering seed‐eating passerines, in ‘core’ areas of lowland Scotland. Methods Ninety‐five Scottish 10‐km squares were selected that held high numbers of seed‐eating passerines in the 1981–84 Atlas of Wintering Birds in Britain and Ireland. The same survey methods were used to resurvey these in winters 1997/98 and 1998/99, and visits were matched as closely as possible for duration and date. Analyses compared counts between the two survey periods for 16 species of seed‐eating passerines and, for 12 of these, differences were also compared with national breeding population trend information for the same period. Results Mean Corn Bunting Emberiza calandra count per visit declined by 62% between the early 1980s and late 1990s, a difference which was statistically significant (P = 0.026). Significant increases were recorded for Yellowhammer Emberiza citrinella (up 62%), Common Linnet Carduelis cannabina (up 3.4‐fold) and European Goldfinch Carduelis carduelis (up 13‐fold). For 12 species for which national breeding population trend data were available, trends were weakly positively correlated (r s = 0.43, P = 0.08) with those from our results, but several species trends were more positive in our study. This difference was particularly marked for Eurasian Tree Sparrow Passer montanus, Goldfinch and Linnet. Conclusion Repeating Winter Atlas surveys offers a useful additional method for assessing population trends. They are particularly useful in a region with low observer coverage and for species that are poorly covered by long‐term bird monitoring data sets. It would be valuable to validate this approach at a regional level, especially in a region for which detailed long‐term bird monitoring data are available.

The effect of supplementary winter seed food on breeding populations of farmland birds: evidence from two large‐scale experiments

Summary Low winter food availability is probably critical in the declines of many farmland bird species in Europe, leading to the implementation of ameliorative agri‐environment scheme options. To date, however, there has been no experimental test of the effectiveness of such options. We report the results of two large‐scale, 3‐year, controlled experiments investigating the effects of supplementary winter seed provision on breeding farmland bird abundance. In each experiment, the use of winter feeding sites by birds was monitored and the availability of alternative, seed‐rich habitat in the surrounding area was measured. The Winter Food for Birds (WFFB) project also included variable levels of food provision. Breeding bird abundance was then monitored in experimental and control areas. The Bird Aid project targeted yellowhammer Emberiza citrinella L., corn bunting Emberiza calandra L. and tree sparrow Passer montanus L., while WFFB considered 11 species that used supplementary winter food. Comparisons of trends in breeding abundance between experimental and control areas revealed little evidence for positive effects of feeding, but there was great variation in the use of feeding sites by each species, and therefore in the seed quantity birds received. Declines for yellowhammer, robin and dunnock were less steep where more food was provided in WFFB areas (a fourfold difference in seed provision across 1·5 times the land area). Analysing trends with respect to weight‐of‐use of winter food revealed significant, positive relationships for yellowhammer (both projects) and up to five other species, depending on the control terms applied. Thus, positive effects of feeding on population change depend on the effective supply of seed to the species of interest. The hypothesis that winter food is currently limiting the populations concerned is also supported. Synthesis and applications. Effective winter food provision to farmland bird populations has the potential to halt, and perhaps to reverse, declines in abundance. In practice, this means that agri‐environment measures supplying significant quantities of winter food, such as stubbles preceded by low‐input cereals, should succeed in changing population trends if they provide resources at the times of greatest need and if there is sufficient uptake.