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Capsule: Transect-based common bird monitoring methods and opportunistic data from citizen scientists are not equal alternatives to mapping of raptors in study plots.Aims: To analyse the ef...

Precise timing of migration is crucial for animals targeting seasonal resources at locations encountered across their annual cycle. Upon departure, long-distance migrants need to anticipate unknown environmental conditions at their arrival site, and they do so with their internal annual clock. Here, we tested the hypothesis that long-distance migrants synchronize their circannual clock according to the phenology of their environment during the breeding season and therefore adjust their spring departure date according to the conditions encountered at their breeding site the year before. To this end, we used tracking data of Eurasian curlews from different locations and combined movement data with satellite-extracted green-up dates at their breeding site. The spring departure date was better explained by green-up date of the previous year, while arrival date at the breeding site was better explained by latitude and longitude of the breeding site, suggesting that other factors impacted migration timing en route . On a broader temporal scale, our results suggest that long-distance migrants may be able to adjust their migration timing to advancing spring dates in the context of climate change.

SummaryThe Numeniini is a tribe of 13 wader species (Scolopacidae, Charadriiformes) of which seven are Near Threatened or globally threatened, including two Critically Endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian- Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species.

Ortolan buntings Emberiza hotulana have undergone one of the most severe population declines of any European farmland bird over the last thirty years. The aim of this study was to find out which habitat features, including crop characteristics, ortolan bunting prefers in Estonia in breeding areas. This study compared currently occupied and unoccupied ortolan bunting territories. Occupied areas contained significantly more tall broadleaf trees, crop types, structural elements (trees, bushes, roads, overhead power lines and buildings) and spring wheat, but also had lower crop drilling densities. Ortolan bunting territories were best described by a logistic regression model containing six variables: amount of structural point elements, length of power lines, amount of tall broadleaf trees and number of different crops had a positive effect, whereas crop density and area of autumn-sown crops had a negative effect. Based on the findings of this study, the following conservation measures can be recommended: lower crop densities; spring rather than autumn-sown crops; small-field systems containing a variety of crops; scattered scrub preserved or planted; habitat patches of permanent grasslands, hedges and tall broadleaf trees retained within the agricultural landscape.

Anthropogenic activities, such as agricultural intensification, caused large declines in biodiversity, including farmland birds. In addition to demographic consequences, anthropogenic activities can result in loss of genetic diversity, reduction of gene flow and altered genetic structure. We investigated the distribution of the genetic variation of a declining farmland and long- distance migratory bird, the ortolan bunting Emberiza hortulana, across its European breeding range to assess the impact of human-driven population declines on genetic diversity and structure in order to advise conservation priorities. The large population declines observed have not resulted in dramatic loss of genetic diversity, which is moderate to high and constant across all sampled breeding sites. Extensive gene flow occurs across the breeding range, even across a migratory divide, which contributes little to genetic structuring. However, gene flow is asymmetric, with the large eastern populations acting as source populations for the smaller western ones. Furthermore, breeding populations that underwent the largest declines, in Fennoscandia and Baltic countries, appear to be recently isolated, with no gene exchange occurring with the eastern or the western populations. These are signs for concern as declines in the eastern populations could affect the strength of gene flow and in turn affect the western populations. The genetic, and demographic, isolation of the northern populations make them particularly sensitive to loss of genetic diversity and to extinction as no immigration is occurring to counter-act the drastic declines. In such a situation, conservation efforts are needed across the whole breeding range: in particular, protect- ing the eastern populations due to their key role in maintaining gene flow across the range, and focussing on the northern populations due to their recent isolation and endangered status.

Farmland biodiversity dramatically declined in Europe during the 20th century. Agri-environment schemes (AES) were introduced in the late 1980s in European Union countries as a solution to combat biodiversity decline. We examined the effectiveness of AES in enhancing biodiversity in a new EU member country (Estonia) over the period of 2010–2012. We compared species numbers and abundance of bumblebees and birds, plus cover of flowers, between three farming systems in two regions of Estonia. Farm types included conventional and two under AES (organic and a less strict environmentally friendly management agreement). Environmentally friendly management practices in Estonia include diversified crop rotations, at least 15% of arable land (including rotational grasslands) under legumes, permanent grassland strips, protection of landscape elements, reduced applications of agrochemicals, etc. The two selected regions (North and South) differed in landscape structure, soil types and crop yields. Flower cover and bird species richness and abundance without the dominant species (skylark) were higher on organic farms. Bumblebee species richness was significantly higher under both types of AES than under conventional farming. Flower cover, abundance and species richness of bumblebees and birds were significantly higher in the more heterogeneous landscapes of Southern Estonia. Environmentally friendly management may be a viable alternative to organic farming for a widely accepted, simple but large-scale greening of agricultural landscapes.

Landscape structure affects farmland bird species richness and diversity at different scales. We develop a predictive, metric-based model for farmland bird species richness in different bird guilds and study how the research area size influences the relationship between bird diversity and landscape metrics. Thirty research locations (randomly selected, each containing four counting points) were located in three counties of Estonia. In early summer 2002 and 2004, two bird counts per point were carried out in each research location. Three landscape metrics (patch density, edge density and Shannon’s diversity index) were calculated at three spatial scales: 100- and 200-m buffer zones around the count points and in a 1 km2 at 1 m × 1 m grain size. Using generalized additive mixed models with repeated measures, we found in most cases that the proportion of variance explained between the bird variables and landscape metrics increased with an increased study area thus demonstrating the effect of scale. Thus, a larger research area is recommended for landscape metrics. At large scales, however, all used landscape metrics were equally good predictors for bird species richness.

Global climate change is a major threat to biodiversity. Large-scale analyses have generally focused on the impacts of climate change on the geographic ranges of species, and on phenology, the timing of ecological phenomena. Here, we use long-term monitoring of the abundance of breeding birds across Europe and the USA to produce, for both regions, composite population indices for two groups of species: those for which climate suitability has been either improving or declining since 1980. The ratio of these composite indices, the Climate Impact Indicator (CII), reflects the divergent fates of species favored or disadvantaged by climate change. The trend in CII is positive and similar in the two regions. On both continents, interspecific and spatial variation in population abundance trends are well predicted by climate suitability trends. This work has been part-funded by the Royal Society for the Protection of Birds, the European Environment Agency, European Commission, and by Durham University’s Grevillea Trust.

Among 66 Estonian farms, representing three subsidy types, birds (especially Sylvia communis and Saxicola rubetra) were more abundant in organic farms that received the largest subsidies and were typically situated in structurally diverse landscapes with a high share of grasslands. Vertical landscape elements most clearly promoted species richness of breeding birds and S. communis. However, among management-related environmental factors considered, only fertilizer input was consistently subsidy-type dependent (highest inputs at medium subsidy levels). High inputs reduced species richness of breeding birds and the density of Alauda arvensis. When environmental factors were accounted for, no significant influences of the subsidy type on birds were observed, but region-specificity remained significant. Our results indicate that differentiation of national subsidies in the AES framework does not necessarily lead to distinct environmental effects, and that targeting of the subsidies on particular species is necessary to effectively improve current environmental conditions.

There was a clear indication that the more intensively farmed areas across the Baltic States of Estonia, Latvia and Lithuania provided habitat for fewer bird species and individuals. The abundance of farmland specialist birds was significantly lower by 20% in the more intensive areas as compared to less intensive ones. The difference could partly be explained by the more heterogeneous landscape and field areas in the latter. An analysis of the data from homogeneous arable fields indicated that agricultural intensification was reflected in a tangible decrease in farmland bird abundance, especially in species in need of edge structures. Considerable improvements are needed in conservation safeguards for the region facing intensification of production.

Following recent updates proposed by BirdLife International and further updates across Europe gathered in the context of a continent-wide study of the migration strategy of the species, we propose here an update of national population sizes and associated recent trends of the Ortolan Bunting (Emberiza hortulana). Previous estimates for the period 1999-2002 reported 5'200'000 to 16'000'000 breeding pairs, for an area extending east to European Russia, and south to the Caucasus and Turkey. The countries holding the largest populations were Turkey (3-10 million pairs) and Russia (1.5-5.0 million pairs). The updated results give approximately 3'319'000 to 7'057'000 pairs in Europe (for the period 2012-2014), representing a c. 50% decrease in numbers over the last decade. This decrease is partly due to overestimates proposed in previous reports for the key country, Turkey, which is now considered to support only 5000'000 to 1'000'000 pairs. Russia still holds 2.0-4.3 million pairs, although with an estimated decline of c. 15-30% since 2000. Overall, within the 39 European countries assessed here, recent decadal trends (on average 2000-2012) in population size are reported as unknown in 15 countries, increasing in 2 countries (Germany and Serbia), stable or fluctuating in 6 countries, and decreasing in 16 countries including recent extinctions in Belgium, Hungary, Slovakia and the Netherlands. Overall, declining populations are mostly located in northern Europe, and fourteen of the 15 northern European countries with a known national trend have declining breeding populations, suggesting that northern breeders are of particular conservation concern.

The general structure of farmland bird communities in Estonia, Latvia and Lithuania was explored based on the large-scale survey in 2002. Input of major farmed habitats to the species richness and abundance of all bird species and groups of farmland specialist and declining species, as well as the abundance of individual farmland species across the region were assessed. The contribution of these to the communities. characteristics and the abundance of a number of farmland species varied across the region. Fewer species were associated with crop fields, especially where farmland was dominated by arable production. There abandoned fields featured as a positive predictor. More species were related to the presence of natural grasslands in the North and seeded grassland in the South of the region. The variation reflected the geographical position and differences in the fragmentation level of farmland, soil types and vegetation development pattern. The results are discussed in relation to agri-environment plann...