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Changes in the intensity and extent of farmland have a profound impact on life on Earth. Although nature-rich farmlands have conservation value, their promotion competes with the protection and restoration of natural habitat. Restoring the productive capacity of existing farmland can help maximize opportunities for the restoration of both nature-rich farmlands and natural habitat.

Determining the links between breeding populations and the pressures, threats and conditions they experience presents a challenge for the conservation of migratory birds which can use multiple sites separated by hundreds to thousands of kilometres. Furthermore, migratory connectivity – the connections made by migrating individuals between networks of breeding and non‐breeding sites – has important implications for population dynamics. The Whinchat Saxicola rubetra is declining across its range, and tracking data from a single African non‐breeding site implies high migratory spread. We used geolocators to describe the migration routes and non‐breeding areas of 20 Whinchats from three British breeding populations. As expected, migratory spread was high, with birds from the three populations overlapping across a wide area of West Africa. On average, in non‐breeding areas, British breeding Whinchats were located 652 km apart from one another, with some likely to share non‐breeding areas with individuals from breeding populations as far east as Russia. Four males made a direct non‐breeding season movement to a second, more westerly, non‐breeding location in January. Autumn migration was through Iberia and around the western edge of the Sahara Desert, whereas spring migration was more direct, indicating an anticlockwise loop migration. Weak migratory connectivity implies that Whinchat populations are somewhat buffered against local changes in non‐breeding conditions. If non‐breeding season processes have played a role in the species’ decline, then large‐scale drivers are likely to be the cause, although processes operating on migration, or interactions between breeding and non‐breeding processes, cannot be ruled out.

Migratory connectivity describes the extent to which different individuals from specific breeding populations use similar non‐breeding sites, with important consequences for the demography and population structure of birds. We used mark‐recapture data from the EUring data bank to describe the non‐breeding range of Twite Linaria flavirostris within Western Europe. We quantified the strength of migratory connectivity across all European breeding populations, and for the British and continental breeding populations separately. Twite from different parts of the British breeding range used different non‐breeding areas from one another, whereas Twite from different parts of the continental breeding range used similar non‐breeding areas. There was essentially no overlap during the non‐breeding season between British and continental Twite.

Empirical evidence from many regions suggests that most species would be least negatively affected if human food demand were met through high-yield agricultural production and conservation of nonfarm ecosystems (land sparing), rather than through wildlife-friendly farming over a larger area (land sharing). However, repeated glaciation and a long history of agriculture may lead to different results in regions such as western Europe. We compared the consequences of land sparing and land sharing on breeding bird species in 2 lowland regions of England, The Fens, with 101 species, and Salisbury Plain, with 83. We derived density-yield responses for each species and then estimated regional population size under regional food production strategies, including land sharing and land sparing, a range of intermediate strategies, and a novel mixed strategy. In both regions, more species achieved maximum regional population size under land sparing than land sharing. In The Fens, the majority of birds were loser species (estimated to have smaller populations under all food production strategies than in the preagricultural baseline scenario), whereas in Salisbury Plain the majority were winners (smaller populations in the preagricultural baseline scenario). Loser species overwhelmingly achieved maximum regional population size under land sparing, whereas winner species achieved maximum regional population size under either land sharing or an intermediate strategy, highlighting the importance of defining which groups of species are the target of conservation. A novel 3-compartment strategy (combining high-yield farming, natural habitat, and low-yield farming) often performed better than either land sharing or land sparing. Our results support intermediate or 3-compartment land-sparing strategies to maximize bird populations across lowland agricultural landscapes. To deliver conservation outcomes, any shift toward land sparing must, however, ensure yield increases are sustainable in the long term, do not entail increased negative effects on surrounding areas, and are linked to allocation of land for nature.Conservación de Aves y el Continuo de Suelo Compartido-Reservado en Paisajes Dominados por Tierras de Cultivo en las Tierras Bajas de Inglaterra Resumen La evidencia empírica proveniente de muchas regiones sugiere que la mayoría de las especies se verían menos afectadas negativamente si se cumpliera con la demanda humana de alimentos por medio de una producción agrícola de alto rendimiento y la conservación de ecosistemas no agrícolas (dosificación de suelo) en lugar de hacerlo a través de la agricultura amigable con la fauna en un área mayor (partición de suelo). Sin embargo, la glaciación repetitiva y una larga historia agrícola podrían brindar diferentes resultados en regiones como Europa occidental. Comparamos las consecuencias de la dosificación y la partición de suelo sobre especies de aves en reproducción en dos regiones de tierras bajas en Inglaterra: Los Fens, con 101 especies, y la Planicie Salisbury, con 83 especies. Derivamos las respuestas con densidad de rendimiento para cada especie y después estimamos el tamaño poblacional regional bajo estrategias regionales de producción de alimentos, incluyendo la dosificación y la partición de suelo, una gama de estrategias intermedias y una novedosa estrategia mixta. En ambas regiones, más especies alcanzaron el tamaño poblacional máximo para la región bajo la dosificación del suelo que bajo la partición del suelo. En Los Fens, la mayoría de las aves fueron especies perdedoras (se estimó que tendrían tamaños poblacionales menores bajo todas las estrategias de producción de alimento que en el escenario pre-agrícola de la línea base) mientras que en la Planicie Salisbury, la mayoría de las especies fueron ganadoras (con poblaciones más pequeñas en el escenario pre-agrícola de la línea base). Las especies perdedoras tuvieron abrumadoramente un tamaño poblacional máximo para la región bajo la dosificación de suelo, mientras que las especies ganadoras tuvieron este máximo poblacional bajo la partición de suelo o alguna estrategia intermedia, lo que resalta la importancia de la definición de cuáles grupos de especies son el objetivo de conservación. Una estrategia novedosa de tres compartimentos (combina la agricultura de alto rendimiento, el hábitat natural y la agricultura de bajo rendimiento) muchas veces tuvo un mejor desempeño que la dosificación o la partición del suelo. Nuestros resultados respaldan a las estrategias de dosificación de suelo intermedias o de tres compartimentos para maximizar las poblaciones de aves en todos los paisajes agrícolas de las tierras bajas. Para brindar resultados de conservación, cualquier cambio hacia la dosificación del suelo, sin embargo, debe asegurar que los incrementos en el rendimiento son sustentables a largo plazo, no conllevan un incremento de efectos negativos en las áreas circundantes, y que están vinculados a la asignación de suelo para la naturaleza.来自许多地区的经验证据表明, 如果人类通过高产农业和保护非农业生态系统的方式 (土地分离) 来满足粮食需求, 而不是通过在较大范围内开展野生动物友好型农业 (土地共享), 那么大多数物种受到的负面影响会是最小的。然而, 一些地区 (如西欧) 经历过多次冰川作用, 且有着悠久的农业历史, 可能在这个问题上有所不同。我们比较了英国两个低地地区土地分离和土地共享对繁殖鸟类的影响, 其中东部沼泽地区 (The Fens) 有 101 种鸟, 索尔斯堡平原 (Salisbury Plain) 有 83 种鸟。我们估计了每个物种的密度-产量响应关系, 并评估了各种区域粮食生产策略下鸟类的区域种群大小, 这些策略包括土地分离、土地共享、一系列中间型策略以及一种新型混合策略。在这两个地区, 较多物种在土地分离策略 (而不是土地共享策略) 下的区域种群大小最大。在沼泽地区, 大部分鸟类物种属于失败者 (据估计, 它们在任何粮食生产策略下的种群数量都低于未发展农业时的基线水平); 而索尔斯堡平原的大多数鸟类物种都是成功者 (未发展农业时的基线水平更低) 。失败物种绝大多数都在土地分离策略下可以达到最大区域种群数量, 而成功物种则会在土地共享或中间型策略下达到最大区域种群数量。这一结果突显了确定保护目标中鸟类类型的重要性。此外, 还存在一种新型的三区分隔策略 (结合了高产农业、自然生境和低产农业), 它的效果往往比单一的土地分离或土地共享更好。我们的结果支持选择中间型或三区分隔型土地分离策略, 以求在低地农业景观中使鸟类种群数量最大化。然而, 要取得保护成效, 还应确保在向土地分离策略的转型中, 产量的增长可长期持续、不会为周围地区带来更多负面影响, 且与自然用地的分配相关联。【翻译: 胡怡思; 审校: 聂永刚】.

Land sparing has been proposed as a strategy to reconcile biodiversity conservation with agricultural production, with empirical studies on five continents indicating that most species would benefit if food demand was met through high‐yield farming combined with the protection or restoration of natural habitat. Most such studies come from landscapes covered by large areas of natural habitat and without a long history of intense human modification. However, much of Europe consists of human‐dominated landscapes, where biodiversity responses to land sparing may differ. To test this, we use estimates of bird population density in different (semi‐)natural habitats, and forecasts of population density in farmland habitat, to assess the future consequences for birds of land‐sparing scenarios in the United Kingdom. Our scenarios predict that whilst up to 18 of the 156 species assessed (predominantly farmland associated species) might decline in UK conservation status under land sparing, up to 35 UK bird species (mainly woodland and wetland species) might improve in status. This contrasts with a maximum of eight species likely to improve in conservation status without land sparing, with up to seven species deteriorating. Combining land sparing with demand management measures (reducing food waste and the consumption of animal products) led to more positive population changes under all scenarios. Synthesis and applications. Land sparing has the potential to benefit UK bird populations in aggregate but would likely have negative impacts on farmland bird species. These findings are likely to be applicable across human‐dominated landscapes beyond the UK, though effects on other taxa, implementation mechanisms and the sustainability of higher yields all require careful consideration.

1. Understanding how to allocate land for the sustainable delivery of multiple, competing objectives is a major societal challenge. The land sharing‐sparing framework presents a heuristic for understanding the trade‐off between food production and biodiversity conservation by comparing region‐wide land‐use scenarios which are equivalent in terms of overall food production. 2. Here, for two contrasting regions of lowland England (The Fens and Salisbury Plain), we use empirical data and predictive models to compare a suite of spatially explicit scenarios reflecting the full range of the sharing‐sparing continuum, including mixed scenarios which combine elements of both sharing and sparing. We evaluate a range of outcomes (bird populations, global warming potential (GWP), nitrogen and phosphorus pollution and outdoor recreation), to identify approaches to regional land‐use planning with the potential to deliver multiple societal benefits. 3. Land‐sharing scenarios (which reduce the dominance of productive agricultural land in farmed areas and the area of larger unfarmed areas) result in negative outcomes, particularly for birds and GWP. In contrast, many land‐sparing scenarios (including mixed scenarios which increase the area of lower‐yield farmland alongside larger unfarmed areas) resulted in improvements in all or most outcomes, although for recreation and nutrient export differences between scenarios were modest. 4. Importantly, environmental outcomes also depended on the spatial arrangement of spared land, the types of natural or semi‐natural habitat promoted on spared land, whether some lower‐yield farmland is delivered alongside larger unfarmed areas, and the overall region‐wide food production target. 5. Policy implications. Our study suggests that land‐sparing strategies which increase the area of natural and semi‐natural areas can improve environmental outcomes, despite the costs associated with high‐yield agriculture. However, high‐yield agriculture should not compromise future production or the conservation value of spared land, and explicit policies such as certification or payments for ecosystem services are required to link sustainable high‐yield production to habitat conservation. Our study also highlights the importance of mitigating projected increases in food demand.

Conservation science is a crisis-oriented discipline focused on delivering robust answers to reducing human impacts on nature. To explore how the field might have changed during the past two decades, we analyzed 3,245 applications for oral presentations submitted to the Student Conference on Conservation Science (SCCS) in Cambridge, UK. SCCS has been running every year since 2000, aims for global representation by providing bursaries to early-career conservationists from lower-income countries, and has never had a thematic focus, beyond conservation in the broadest sense. We found that the majority of submissions to SCCS were based on primary biological data collection from local scale field studies in the tropics, contrary to established literature which highlights gaps in tropical research. Our results showed a small increase over time in submissions framed around how nature benefits people as well as a small increase in submissions integrating social science. Our findings also suggest that students and early-career conservationists could provide pathways to increased availability of data from the tropics and for addressing well-known biases in the published literature towards wealthier countries. We hope this research will motivate efforts to support student projects, ensuring data and results are published and made publicly available.

To maximize the effectiveness of conservation interventions, it is crucial to have an understanding of how intraspecific variation determines the relative importance of potential limiting factors. For bird populations, limiting factors include nest‐site availability and foraging resources, with the former often addressed through the provision of artificial nestboxes. However, the effectiveness of artificial nestboxes depends on the relative importance of nest‐site vs. foraging resource limitations. Here, we investigate factors driving variation in breeding density, nestbox occupation and productivity in two contrasting study populations of the European Roller Coracias garrulus, an obligate cavity‐nesting insectivorous bird. Breeding density was more than four times higher at the French study site than at the Latvian site, and there was a positive correlation between breeding density (at the 1‐km2 scale) and nest‐site availability in France, whereas there was a positive correlation between breeding density and foraging resource availability in Latvia. Similarly, the probability of a nestbox being occupied increased with predicted foraging resource availability in Latvia but not in France. We detected no positive effect of foraging resource availability on productivity at either site, with most variation in breeding success driven by temporal effects: a seasonal decline in France and strong interannual fluctuations in Latvia. Our results indicate that the factors limiting local breeding density can vary across a species' range, resulting in different conservation priorities. Nestbox provisioning is a sufficient short‐term conservation solution at our French study site, where foraging resources are typically abundant, but in Latvia the restoration of foraging habitat may be more important. density can vary across a species’ range, resulting in different conservation priorities. Nest-box provisioning is a sufficient short-term conservation solution at our French study site, where foraging resources are typically abundant, but in Latvia the restoration of foraging habitat may be more important.

In the version of this Article originally published, ammonia and NO emissions (and associated N deposition), nitrate leaching, and the CO emitted during urea hydrolysis following application to land were all accidentally omitted in the comparison of the greenhouse gas impacts of using ammonium nitrate and urea to produce wheat grain.

A recent paper claiming evidence of global insect declines achieved huge media attention, including claims of "insectaggedon" and a "collapse of nature." Here, we argue that while many insects are declining in many places around the world, the study has important limitations that should be highlighted. We emphasise the robust evidence of large and rapid insect declines present in the literature, while also highlighting the limitations of the original study.

How society responds to rising human food needs will be pivotal to the future of global biodiversity1–3. Cutting food waste and consumption of ruminant meat are essential2–5 . On the supply side, detailed field data from five continents consistently show extinctions would be greatly reduced if residual demand could be met by land sparing - boosting yields (production per unit area) on existing farmland while conserving (or restoring) remaining natural habitats6,7. But limiting the land cost of agriculture through high-yield farming raises other important concerns because when expressed per unit area, high-yield systems can generate high levels of negative externalities such as greenhouse gas (GHG) emissions and nutrient emissions 8,9losses8,9. However, such metrics systematically underestimate the overall impacts of lower-yield systems. Here we instead develop a framework quantifying externality costs (including off-site effects) per unit of production. Applying this more comprehensive approach to five key externalities and four major farm sectors, we discover that, rather than associations between externality and land costs of alternative production systems being characterised by trade-offs (i.e. negative correlations), those for which we could find data more commonly exhibit positive correlations. Per- unit production, systems which take up less land often generate fewer externalities. For GHG emissions (the best-documented externality) these associations become more strongly positive once the effects of land use are included. Our conclusions are limited by data availability – remarkably few studies quantify externalities alongside yields, and many important externalities remain largely unmeasured. Moreover, some high-yield systems we examined have high externality costs, even per- unit of production, and none can generate environmental benefits unless linked with efforts to limit rebound effects10,11. However, our results identify several promising ways of increasing yields while lowering other environmental impacts, and more generally suggest that trade-offs among key cost metrics are not as ubiquitous as sometimes perceived.

Long-distance migratory bird populations are likely to be declining because of climate change shifting habitats or anthropogenic habitat loss [1], but this may be mediated by the size of the non-breeding area over which a population spreads (migratory spread), and migration distance (or number of stop-over sites). High migratory spread may make populations more resilient to climate change because they already encompass shifting habitats, but less resilient to uneven habitat loss that may not affect populations with low migratory spread [2] (Figure 1C). As migration distance increases so the probability of encountering a stop-over site with negative environmental change increases [3] (Figure 1D). Consequently, if habitat shift through climate change is the main driver of declines we predict more positive population trends for high spread migrants, but the reverse for outright habitat loss (Figure 1E); we also predict negative population trends for longer distance migrants (Figure 1F). But these relationships may vary between flyways, which differ profoundly in their climate variation, human population change and geography. Here we show that climate change may be more important in Neotropic migrant population declines whereas habitat loss may be more important in the Afro-Palearctic. Postprint

Businesses are under constant pressure to make tighter budgets go further than ever. In this article, Tom Finch describes how re-examining a home's supply chain can not only help cut costs, but also aid during an inspection from the Care Quality Commission

TF benefitted from a Natural Environment Research Council studentship (student number 6109659) and AF from a Natural Environment research grant NE/K006321/1. 1. Estimating how much long-distance migrant populations spread out and mix during the non-breeding season (migratory connectivity) is essential for understanding and predicting population dynamics in the face of global change. 2. We quantify variation in population spread and inter-population mixing in long- distance, terrestrial migrant land-bird populations (712 individuals from 98 populations of 45 species, from tagging studies in the Neotropic and Afro-Palearctic flyways). We evaluate the Mantel test as a metric of migratory connectivity, and explore the extent to which variance in population spread can be explained simply by geography. 3. The mean distance between two individuals from the same population during the non- breeding season was 743 km, covering 10–20% of the maximum width of Africa / South America. Individuals from different breeding populations tended to mix during the non-breeding season, though spatial segregation was maintained in species with relatively large non-breeding ranges (and, to a lesser extent, those with low population-level spread). A substantial amount of between-population variation in population spread was predicted simply by geography, with populations using non- breeding zones with limited land availability (e.g. Central America compared to South America) showing lower population spread. 4. The high levels of population spread suggest that deterministic migration strategies are not generally adaptive; this makes sense in the context of the recent evolution of the systems, and the spatial and temporal unpredictability of non-breeding habitat. 5. The conservation implications of generally low connectivity are that the loss (or protection) of any non-breeding site will have a diffuse but widespread effect on many breeding populations. Although low connectivity should engender population resilience to shifts in habitat (e.g. due to climate change), we suggest it may increase susceptibility to habitat loss. We hypothesise that because a migrant species cannot adapt to both simultaneously, migrants generally may be more susceptible to population declines in the face of concurrent anthropogenic habitat and climate change. Publisher PDF

The relation between obesity and Social Withdrawal Syndrome (SWS) was examined using the data gathered by Rotenberg, Bharathi, Davies, and Finch (2013). One hundred and 35 undergraduates (80 females; Mage=21years-10months) completed standardized scales that assessed the SWS (low emotional trust beliefs in close others, low disclosure to close others, and high loneliness). BMI was calculated from self-reported weight and height. As hypothesized, quadratic relations were found in which participants with BMI>30 (i.e., obese) demonstrated the SWS pattern of low emotional trust beliefs in close others, low disclosure to close others, and high loneliness. As further evidence, lower emotional trust in close others, lower disclosure to close others, and greater loneliness were found for obese participants (>30 BMI, n=27) than both normal weight (

The rapid growth of online tools to communicate scientific research raises the important question of whether online attention is associated with citations in the scholarly literature. The Altmetric Attention Score (AAS) quantifies the attention received by a scientific publication on various online platforms including news, blogs and social media. It has been advanced as a rapid way of gauging the impact of a piece of research, both in terms of potential future scholarly citations and wider online engagement. Here, we explore variation in the AAS of 2677 research articles published in 10 ornithological journals between 2012 and 2016. On average, AAS increased sevenfold in just five years, primarily due to increased activity on Twitter which contributed 75% of the total score. For a subset of 878 articles published in 2014, including an additional 323 ornithology articles from non-specialist journals, an increase in AAS from 1 to 20 resulted in a predicted 112% increase in citation count from 2.6 to 5.5 citations per article. This effect interacted with journal impact factor, with weaker effects of AAS in higher impact factor journals. Our results suggest that altmetrics (or the online activity they measure), as well as complementing traditional measures of scholarly impact in ornithology such as citations, may also anticipate or even drive them.

Long distance migrants are declining more rapidly than residents, with birds that breed in Europe and winter in tropical Africa providing particularly clear examples. Causal mechanisms may include climate change, but are poorly understood partly because carry-over effects from non-breeding ranges can influence breeding performance. Using long-term data spanning four decades we assess how climatic variation in migrants’ winter, passage and breeding ranges determine timing of breeding and reproductive success. We do so for three Afro-European avian migrants of regional conservation concern (redstart, spotted flycatcher and wood warbler). We find that carry-over effects from passage regions consistently had stronger impacts on breeding phenology than breeding climate. Warm Mediterranean passage conditions promoted earlier breeding in all species, and redstarts also bred earlier following higher Sahel rainfall. Warmer springs on the breeding grounds promoted slightly earlier breeding in redstart and wood warbler, but not spotted flycatcher. Carry-over effects also typically influenced breeding performance to a greater extent than weather on the breeding grounds. Greater rainfall in the Sahel increased redstart brood size, warmer Mediterranean passage conditions increased spotted flycatcher brood size and, to a lesser extent, the number of wood warbler fledglings. In contrast to the concern regarding climate change impacts on migrants’ breeding grounds we found no evidence that warmer temperatures on the breeding grounds were associated with reduced reproductive performance. We thus find that climatic variation on the non-breeding grounds, especially passage regions, typically influenced migrants’ breeding phenology and demography more strongly than equivalent variation on the breeding sites. Such carry-over effects should be considered when assessing the causes of migrants’ marked population declines.

Despite recent advances in avian tracking technology, archival devices still present several limitations. Traditional ring recoveries provide a complementary method for studying migratory movements, particularly for cohorts of birds with a low return rate to the breeding site. Here we provide the first international analysis of ring recovery data in the European Roller Coracias garrulus, a long-distance migrant of conservation concern. Our data comprise 58 records of Rollers ringed during the breeding season and recovered during the non-breeding season. Most records come from Eastern Europe, half are of juveniles and over three quarters are of dead birds. Thus, ring recoveries provide migration data for cohorts of Rollers—juveniles and unsuccessful migrants—for which no information currently exists, complementing recent tracking studies. Qualitatively, our results are consistent with direct tracking studies, illustrating a broad-front migration across the Mediterranean Basin in autumn and the use of the Arabian Peninsula by Rollers from eastern populations in spring. Autumn movements were, on average, in a more southerly direction for juveniles than adults, which were more easterly. Juvenile autumn recovery direction also appeared to be more variable than in adults, though this difference was not statistically significant. This is consistent with juveniles following a naïve vector-based orientation program, and perhaps explains the ‘moderate’ migratory connectivity previously described for the Roller. In the first (qualitative) analysis of Roller non-breeding season mortality, we highlight the high prevalence of shooting. The recovery age ratio was juvenile-biased in autumn but adult-biased in spring. Although not statistically significant, this difference points towards a higher non-breeding season mortality of juveniles than adults. Our study demonstrates the complementarity of ring recoveries to direct tracking, providing an insight into the migration of juvenile Rollers and non-breeding season mortality.

One hundred and thirty-seven undergraduates (81 females; mean age = 21 years–10 months) completed the Bulimic SEDS subscale and standardized measures of trust beliefs in close others (mother, father, and friend), disclosure to them, and loneliness. Structural Equation Modelling yielded: (1) a negative path between Bulimic Symptoms and trust beliefs, (2) a positive path between trust beliefs and disclosure, (3) a negative path between trust beliefs and loneliness, and (4) a negative path between disclosure and loneliness. As expected, trust beliefs statistically mediated the relations between Bulimic Symptoms and both disclosure and loneliness and disclosure statistically mediated the relation between trust beliefs and loneliness. The findings supported the conclusion that individuals with bulimia nervosa are prone to the social withdrawal syndrome comprising a coherent and integrated pattern of low trust beliefs in close others, low disclosure to close others, and high loneliness.

In common with many other insectivorous birds, the Common Swift Apus apus is undergoing population declines, with an estimated 57% reduction in abundance between 1995 and 2017 in the UK. The ultimate drivers of this decline are poorly understood, but links have been drawn to reductions in the abundance and availability of insect prey, as well as loss of nesting sites. The aim of this study is to improve understanding of the demographic and environmental drivers of Swift decline in Great Britain, with a particular focus on weather and aphid biomass. We explore spatio-temporal trends in the biomass of aphids, an important source of food for these aerial feeders, from a network of seventeen 12.2 m suction-traps. We then use data from national nest recording and ringing schemes to describe temporal trends in, and covariates of, Swift breeding success and annual survival. Demographic data are sparse prior to the mid-1990s but show stable adult survival, a reduction in first-year survival and an increase in nest failure rate since the mid-1970s. Despite marked declines in aphid biomass across much of southern and eastern England during this period, we find no association between aphid biomass and Swift demography. Weather was a stronger correlate of variation in Swift demography, with increased precipitation associated with smaller brood size, higher nest failure rate and lower first-year survival. Our data suggest that falling first-year survival, partly linked to wetter summers, may be the most likely demographic driver of population decline. Given that the only convincing correlates of Swift demography were weather-related, we suggest it would be precautionary for conservation efforts to continue to focus on ensuring that safe and productive nesting sites are in sufficient supply. Further research to identify habitats and land management practices which provide foraging resources, particularly during periods of inclement weather, is required, and future demographic modelling exercises would benefit from increased nest recording and ringing efforts.

Aim The extent to which individuals from different breeding populations mix throughout the non-breeding season (i.e. ‘migratory connectivity’) has important consequences for population dynamics and conservation. Given recent declines of long-distance migrant birds, multipopulation tracking studies are crucial in order to assess the strength of migratory connectivity and to identify key sites en route. Here, we present the first large-scale analysis of migration patterns and migratory connectivity in the globally near-threatened European roller Coracias garrulus. Location Breeding area: Europe; passage area: Mediterranean, sub-Saharan Africa, Arabian Peninsula; wintering area: southern Africa. Methods We synthesize new geolocator data with existing geolocator, satellite tag and ring recovery data from eight countries across Europe. We describe routes and stopover sites, analyse the spatial pattern of winter sites with respect to breeding origin and quantify the strength of connectivity between breeding and winter sites. Results We demonstrate the importance of the northern savanna zone as a stopover region and reveal the easterly spring loop (via Arabia) and leapfrog migration of rollers from eastern populations. Whilst there was some overlap between individuals from different populations over winter, their distribution was non-random, with positive correlations between breeding and autumn/winter longitude as well as between pairwise distance matrices of breeding and winter sites. Connectivity was stronger for eastern populations than western ones. Main conclusions The moderate levels of connectivity detected here may increase the resilience of breeding populations to localized habitat loss on the winter quarters. We also highlight the passage regions crucial for the successful conservation of roller populations, including the Sahel/Sudan savanna for all populations, and the Horn of Africa/Arabian Peninsula for north-eastern rollers.