Forage plants of an Arctic‐nesting herbivore show larger warming response in breeding than wintering grounds,potentially disrupting migration phenology

During spring migration, herbivorous waterfowl breeding in the Arctic depend on peaks in the supply of nitrogen‐rich forage plants, following a “green wave” of grass growth along their flyway to fuel migration and reproduction. The effects of climate warming on forage plant growth are expected to be larger at the Arctic breeding grounds than in temperate wintering grounds, potentially disrupting this green wave and causing waterfowl to mistime their arrival on the breeding grounds. We studied the potential effect of climate warming on timing of food peaks along the migratory flyway of the Russian population of barnacle geese using a warming experiment with open‐top chambers. We measured the effect of 1.0–1.7°C experimental warming on forage plant biomass and nitrogen concentration at three sites along the migratory flyway (temperate wintering site, temperate spring stopover site, and Arctic breeding site) during 2 months for two consecutive years. We found that experimental warming increased biomass accumulation and sped up the decline in nitrogen concentration of forage plants at the Arctic breeding site but not at temperate wintering and stop‐over sites. Increasing spring temperatures in the Arctic will thus shorten the food peak of nitrogen‐rich forage at the breeding grounds. Our results further suggest an advance of the local food peak in the Arctic under 1–2°C climate warming, which will likely cause migrating geese to mistime their arrival at the breeding grounds, particularly considering the Arctic warms faster than the temperate regions. The combination of a shorter food peak and mistimed arrival is likely to decrease goose reproductive success under climate warming by reducing growth and survival of goslings after hatching.     

Global change and the distributional dynamics of migratory bird populations wintering in Central America

Understanding the susceptibility of highly mobile taxa such as migratory birds to global change requires information on geographic patterns of occurrence across the annual cycle. Neotropical migrants that breed in North America and winter in Central America occur in high concentrations on their non‐breeding grounds where they spend the majority of the year and where habitat loss has been associated with population declines. Here, we use eBird data to model weekly patterns of abundance and occurrence for 21 forest passerine species that winter in Central America. We estimate species’ distributional dynamics across the annual cycle, which we use to determine how species are currently associated with public protected areas and projected changes in climate and land‐use. The effects of global change on the non‐breeding grounds is characterized by decreasing precipitation, especially during the summer, and the conversion of forest to cropland, grassland, or peri‐urban. The effects of global change on the breeding grounds are characterized by increasing winter precipitation, higher temperatures, and the conversion of forest to peri‐urban. During spring and autumn migration, species are projected to encounter higher temperatures, forests that have been converted to peri‐urban, and increased precipitation during spring migration. Based on current distributional dynamics, susceptibility to global change is characterized by the loss of forested habitats on the non‐breeding grounds, warming temperatures during migration and on the breeding grounds, and declining summer rainfall on the non‐breeding grounds. Public protected areas with low and medium protection status are more prevalent on the non‐breeding grounds, suggesting that management opportunities currently exist to mitigate near‐term non‐breeding habitat losses. These efforts would affect more individuals of more species during a longer period of the annual cycle, which may create additional opportunities for species to respond to changes in habitat or phenology that are likely to develop under climate change.     

Body condition and feather molt of a migratory shorebird during the non‐breeding season

Migratory shorebirds have some of the highest fat loads among birds, especially species which migrate long distances. The upland sandpiper Bartramia longicauda makes long‐distance migrations twice a year, but variation in body condition or timing of feather molt during the non‐breeding season has not been studied. Molt is an important part of the annual cycle of migratory birds because feather condition determines flight performance during migration, and long‐distance movements are energetically costly. However, variation in body condition during molt has been poorly studied. The objective of our field study was to examine the timing and patterns of feather molt of a long distance migratory shorebird during the non‐breeding season and test for relationships with body size, fat depots, mass, and sex. Field work was conducted at four ranches in the Northern Campos of Uruguay (Paysandú and Salto Departments). We captured and marked 62 sandpipers in a 2‐month period (Nov–Jan) during four non‐breeding seasons (2008–2012). Sex was determined by genetic analyses of blood samples taken at capture. Molt was measured in captured birds using rank scores based on published standards. Body mass and tarsus length measurements showed female‐biased sexual size dimorphism with males smaller than females. Size‐corrected body mass (body condition) showed a U‐shaped relationship with the day of the season, indicating that birds arrived at non‐breeding grounds in relatively good condition. Arriving in good body condition at non‐breeding grounds is probably important because of the energetic demands due to physiological adjustments after migration and the costs of feather molt.     

Spring migratory routes and stopover duration of satellite‐tracked Eurasian Teals Anas crecca wintering in Italy

Identifying an organism's migratory strategies and routes has important implications for conservation. For most species of European ducks, information on the general course of migration, revealed by ringing recoveries, is available, whereas tracking data on migratory movements are limited to the largest species. In the present paper, we report the results of a tracking study on 29 Eurasian Teals, the smallest European duck, captured during the wintering period at three Italian sites. The departure date of spring migration was determined for 21 individuals, and for 15 the entire spring migratory route was reconstructed. Most ducks departed from wintering grounds between mid‐February and March following straight and direct routes along the Black Sea‐Mediterranean flyway. The breeding sites, usually reached by May, were spread from central to north‐Eastern Europe to east of the Urals. The migratory speed was slow (approximately 36 km/day on average) because most birds stopped for several weeks at stopover sites, mainly in south‐eastern Europe, especially at the very beginning of migration. The active flight migration segments were covered at much higher speeds, up to 872 km/day. Stopover duration tended to be shorter when birds were closer to their breeding site. These results, based on the largest satellite tracking effort for this species, revealed for the first time the main features of the migratory strategies of individual Teals wintering in Europe, such as the migration timing and speed and stopover localization and duration.     

Broad wintering range and intercontinental migratory divide within a core population of the near‐threatened pallid harrier

Aim To identify the migration routes and wintering grounds of the core populations of the near‐threatened pallid harrier, Circus macrourus, and highlight conservation needs associated with these phases of the annual cycle. Location Breeding area: north‐central Kazakhstan; Wintering areas: Sahel belt (Burkina Faso to Ethiopia) and north‐west India. Methods We used ring recovery data from Kazakhstan and satellite tracking data from 2007 to 2008 on six adults breeding in north‐central Kazakhstan to determine migration routes and locate wintering areas. In addition, one first‐year male was tagged in winter 2007–2008 in India. Results Data evidenced an intercontinental migratory divide within the core pallid harrier population, with birds wintering in either Africa or India. The six individuals tagged in north‐central Kazakhstan followed a similar route (west of the Caspian Sea and Middle East) towards east Africa, before spreading along the Sahel belt to winter either in Sudan, Ethiopia, Niger or Burkina Faso. Spring migration followed a shorter, more direct route, with marked interindividual variation. The bird tagged in India spent the summer in central Kazakhstan. Half of the signal losses (either because of failure or bird mortality) occurred on the wintering areas and during migration. Main conclusions Our study shows that birds from one breeding area may winter over a strikingly broad range within and across continents. The intercontinental migratory divide of pallid harriers suggests the coexistence of distinct migratory strategies within the core breeding population, a characteristic most likely shared by a number of threatened species in central Asia. Conservation strategies for species like the pallid harrier, therefore, require considering very large spatial scales with possibly area‐specific conservation issues. We highlight urgent research priorities to effectively inform the conservation of these species.     

A bridge between oceans: overland migration of marine birds in a wind energy corridor

Located at the shortest overland route between the Gulf of Mexico and the Pacific Ocean, Mexico's Tehuantepec Isthmus is a globally important migratory corridor for many terrestrial bird species. The Pacific coast of the Isthmus also contains a significant wetland complex that supports large multi‐species aggregations of non‐breeding waterbirds during the boreal winter. In recent years, extensive wind energy development has occurred in the plains bordering these wetlands, directly along the migratory flyway. Using recent studies of movement patterns of three marine‐associated bird species – reddish egrets Egretta rufescens, brown pelicans Pelecanus occidentalis, and red knots Calidris canutus – from the northern Gulf of Mexico, we assess the use of the isthmus as a migratory corridor. Our data provide evidence that marine birds from the Gulf region regularly overwinter along the Pacific coast of Mexico and use the isthmus as a migratory corridor, creating the potential for interaction with terrestrial wind farms during non‐breeding. This study is the first to describe migration by marine‐associated bird species between the Gulf of Mexico and Pacific coast. These data contribute new information toward ongoing efforts to understand the complex migration patterns of mobile marine species, with the goal of informing integrated conservation efforts for species whose year‐round habitat needs cross ecoregional and geopolitical boundaries.     

Around the Mediterranean: an extreme example of loop migration in a long‐distance migratory passerine

An important issue in migration research is how small‐bodied passerines pass over vast geographical barriers; in European–African avian migration, these are represented by the Mediterranean Sea and the Sahara Desert. Eastern (passing eastern Mediterranean), central (passing Apennine Peninsula) and western (via western Mediterranean) major migration flyways are distinguished for European migratory birds. The autumn and spring migration routes may differ (loop migration) and there could be a certain level of individual flexibility in how individuals navigate themselves during a single migration cycle. We used light‐level loggers to map migration routes of barn swallows Hirundo rustica breeding in the centre of a wide putative contact zone between the northeastern and southernwestern European populations that differ in migration flyways utilised and wintering grounds. Our data documented high variation in migration patterns and wintering sites of tracked birds (n = 19 individuals) from a single breeding colony, with evidence for loop migration in all but one of the tracked swallows. In general, two migratory strategies were distinguished. In the first, birds wintering in a belt stretching from southcentral to southern Africa that used an eastern route for both the spring and autumn migration, then shifted their spring migration eastwards (anti‐clockwise loops, n = 12). In the second, birds used an eastern or central route to their wintering grounds in central Africa, shifting the spring migration route westward (clockwise loops, n = 7). In addition, we observed an extremely wide clockwise loop migration encompassing the entire Mediterranean, with one individual utilising both the eastern (autumn) and western (spring) migratory flyway during a single annual migration cycle. Further investigation is needed to ascertain whether clockwise migratory loops encircling the entire Mediterranean also occur other small long‐distance passerine species.     

Overtaking on migration: does longer distance migration always incur a penalty?

For many migratory bird species, the latitudinal range of the winter distribution spans thousands of kilometres, thus encompassing considerable variation in individual migration distances. Pressure to winter near breeding areas is thought to be a strong driver of the evolution of migration patterns, as individuals undertaking a shorter migration are generally considered to benefit from earlier arrival on the breeding grounds. However, the influence of migration distance on timing of arrival is difficult to quantify because of the large scales over which individuals must be tracked. Using a unique dataset of individually‐marked Icelandic black‐tailed godwits Limosa limosa islandica tracked throughout the migratory range by a network of hundreds of volunteer observers, we quantify the consequences of migrating different distances for the use of stop‐over sites and timing of arrival in Iceland. Modelling of potential flight distances and tracking of individuals from across the winter range shows that individuals wintering further from the breeding grounds must undertake a stop‐over during spring migration. However, despite travelling twice the distance and undertaking a stop‐over, individuals wintering furthest from the breeding grounds are able to overtake their conspecifics on spring migration and arrive earlier in Iceland. Wintering further from the breeding grounds can therefore be advantageous in migratory species, even when this requires the use of stop‐over sites which lengthen the migratory journey. As early arrival on breeding sites confers advantages for breeding success, the capacity of longer distance migrants to overtake conspecifics is likely to influence the fitness consequences of individual migration strategies. Variation in the quality of wintering and stopover sites throughout the range can therefore outweigh the benefits of wintering close to the breeding grounds, and may be a primary driver of the evolution of specific migration routes and patterns.     

The decline of Afro‐Palaearctic migrants and an assessment of potential causes

There is compelling evidence that Afro‐Palaearctic (A‐P) migrant bird populations have declined in Europe in recent decades, often to a greater degree than resident or short‐distance migrants. There appear to have been two phases of decline. The first in the 1960s–1970s, and in some cases into the early 1980s, largely affected species wintering predominantly in the arid Sahelian zone, and the second since the 1980s has mostly affected species wintering in the humid tropics and Guinea forest zone. Potential drivers of these declines are diverse and are spread across and interact within the migratory cycle. Our knowledge of declining species is generally better for the breeding than the non‐breeding parts of their life cycles, but there are significant gaps in both for many species. On the breeding grounds, degradation of breeding habitats is the factor affecting the demography of the largest number of species, particularly within agricultural systems and woodland and forests. In the non‐breeding areas, the interacting factors of anthropogenic habitat degradation and climatic conditions, particularly drought in the Sahel zone, appear to be the most important factors. Based on our synthesis of existing information, we suggest four priorities for further research: (1) use of new and emerging tracking technologies to identify migratory pathways and strategies, understand migratory connectivity and enable field research to be targeted more effectively; (2) undertake detailed field studies in sub‐Saharan Africa and at staging sites, where we understand little about distribution patterns, habitat use and foraging ecology; (3) make better use of the wealth of data from the European breeding grounds to explore spatial and temporal patterns in demographic parameters and relate these to migratory pathways and large‐scale patterns of habitat change and climatic factors; and (4) make better use of remote sensing to improve our understanding of how and where land cover is changing across these extensive areas and how this impacts A‐P migrants. This research needs to inform and underpin a flyway approach to conservation, evaluating a suite of drivers across the migratory cycle and combining this with an understanding of land management practices that integrate the needs of birds and people in these areas.     

Non‐breeding range size predicts the magnitude of population trends in trans‐Saharan migratory passerine birds

Understanding why populations of some migratory species show a directional change over time, i.e. increase or decrease, while others do not, remains a challenge for ecological research. One possible explanation is that species with smaller non‐breeding ranges may have more pronounced directional population trends, and their populations are thus more sensitive to the variation in environmental conditions in their non‐breeding quarters. According to the serial residency hypothesis, this sensitivity should lead to higher magnitudes (i.e. absolute values) of population trends for species with smaller non‐breeding ranges, with the direction of trend being either positive or negative depending on the nature of the environmental change. We tested this hypothesis using population trends over 2001–2012 for 36 sub‐Saharan migratory passerine birds breeding in Europe. Namely, we related the magnitude of the species' population trends to the size of their sub‐Saharan non‐breeding grounds, whilst controlling for factors including number of migration routes, non‐breeding habitat niche and wetness, breeding habitat type and life‐history strategy. The magnitude of species' population trends grew with decreasing absolute size of sub‐Saharan non‐breeding ranges, and this result remained significant when non‐breeding range size was expressed relative to the size of the breeding range. After repeating the analysis with the trend direction, the relationship with the non‐breeding range size disappeared, indicating that both population decreases and increases are frequent amongst species with small non‐breeding range sizes. Therefore, species with small non‐breeding ranges are at a higher risk of population decline due to adverse factors such as habitat loss or climatic extremes, but their populations are also more likely to increase when suitable conditions appear. As non‐breeding ranges may originate from stochasticity of non‐breeding site selection in naive birds (‘serial‐residency’ hypothesis), it is crucial to maintain a network of stable and resilient habitats over large areas of birds’ non‐breeding quarters.     

The pull of the Central Flyway? Veeries breeding in western Canada migrate using an ancestral eastern route

Understanding non‐breeding season movements and identifying wintering areas of different populations of migratory birds is important for establishing patterns of migratory connectivity over the annual cycle. We analyzed archival solar geolocation (N = 5) and global positioning data (N = 1) to investigate migration routes, stopover sites, and wintering areas of a western‐most breeding population of Veeries (Catharus fuscescens) in the Pemberton Valley, British Columbia, Canada. Geolocation data were analyzed using a Bayesian state‐space model to improve likely position estimates. We compared our results with those from a Veery population located ~250 km east across a mountain chain in the Okanagan Valley, British Columbia, and with an eastern population in Delaware, U.S.A. Migrating Veeries from the Pemberton Valley used an eastern trajectory through the Rocky Mountains to the Great Plains to join a central flyway during fall and spring migration, a route similar to that used by Veeries breeding in the Okanagan Valley. However, wintering destinations of Pemberton Valley birds were more varied, with inter‐individual wintering distances ~1000 km greater than birds from the Okanagan Valley population and ~500 km from the previously known winter range of Veeries. The observed eastern migration path likely follows an ancestral route that evolved following the most recent glacial retreat. Consistent with patterns observed from the Okanagan and Delaware populations, Veeries from the Pemberton Valley undertook an intra‐tropical migration on the wintering grounds, but this winter movement differed from those of previously studied populations. Such winter movements may thus be idiosyncratic or show coarse population associations. Intra‐wintering‐ground movements likely occur either in response to seasonal changes in habitat suitability or as a means of optimizing pre‐migratory fueling prior to long‐distance spring movements to North America.     

Climatic effects on timing of spring migration and breeding in a long-distance migrant, the pied flycatcher Ficedula hypoleuca

Climate change has advanced the breeding dates of many bird species, but for few species we know whether this advancement is sufficient to track the advancement of the underlying levels of the food chain. For the long-distance migratory pied flycatcher Ficedula hypoleuca the advancement in breeding time has been insufficient to maintain the synchrony with their main food sources. The timing of arrival in the breeding areas from their African wintering grounds is likely to constrain the advancement of breeding date. We hypothesise that this is because in Africa they cannot predict the advancement of spring in their breeding habitat. However, long-distance migrants may advance their arrival time by migrating faster when circumstances en route are favourable. In this study we show that both arrival and breeding date depend on temperatures at their main North African staging grounds, as well as on temperature at the breeding grounds. Male arrival and average laying date were not correlated, but the positive effect of temperature in North Africa on breeding dates suggests that breeding date is indeed constrained by arrival of females. Long-distance migrants thus are able to adjust arrival and hence breeding by faster spring migration, but the degree of adjustment is probably limited as timing schedules in spring are tight. Furthermore, as climate change is affecting temperatures differently along the migratory flyway and the breeding areas, it is unlikely that arrival dates are advanced at the same rate as the timing of breeding should advance, given the advancement of the underlying levels of the food chain.     

Circannual variation in blood parasitism in a sub‐Saharan migrant passerine bird,the garden warbler

Knowing the natural dynamics of pathogens in migratory birds is important, for example, to understand the factors that influence the transport of pathogens to and their transmission in new geographical areas, whereas the transmission of other pathogens might be restricted to a specific area. We studied haemosporidian blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon in a migratory bird, the garden warbler Sylvia borin. Birds were sampled in spring, summer and early autumn at breeding grounds in Sweden, on migration at Capri, Italy and on arrival and departure from wintering staging areas in West Africa: mapping recoveries of garden warblers ringed in Fennoscandia and Capri showed that these sites are most probably on the migratory flyway of garden warblers breeding at Kvismaren. Overall, haemosporidian prevalence was 39%, involving 24 different parasite lineages. Prevalence varied significantly over the migratory cycle, with relatively high prevalence of blood parasites in the population on breeding grounds and at the onset of autumn migration, followed by marked declines in prevalence during migration both on spring and autumn passage. Importantly, we found that when examining circannual variation in the different lineages, significantly different prevalence profiles emerged both between and within genera. Our results suggest that differences in prevalence profiles are the result of either different parasite transmission strategies or coevolution between the host and the various parasite lineages. When separating parasites into common vs. rare lineages, we found that two peaks in the prevalence of rare parasites occur; on arrival at Swedish breeding grounds, and after the wintering period in Africa. Our results stress the importance of appropriate taxonomic resolution when examining host‐parasite interactions, as variation in prevalence both between and within parasite genera can show markedly different patterns.     

Connecting the dots: Stopover strategies of an intercontinental migratory songbird in the context of the annual cycle

The phases of the annual cycle for migratory species are inextricably linked. Yet, less than five percent of ecological studies examine seasonal interactions. In this study, we utilized stable hydrogen isotopes to geographically link individual black‐and‐white warblers (Mniotilta varia) captured during spring migration with breeding destinations to understand a migrant's stopover strategy in the context of other phases of the annual cycle. We found that stopover strategy is not only a function of a bird's current energetic state, but also the distance remaining to breeding destination and a bird's time‐schedule, which has previously been linked to habitat conditions experienced in the preceding phase of the annual cycle. Birds in close proximity to their breeding destination accumulate additional energy reserves prior to arrival on the breeding grounds, as reflected by higher migratory condition upon arrival, higher refueling rates measured via blood plasma metabolites, and longer stopover durations compared to birds migrating to breeding destinations farther from the stopover site. However, late birds near their breeding destination were more likely to depart on the day of arrival (i.e., transients), and among birds that stopped over at the site, the average duration of stopover was almost half the time of early conspecifics, suggesting late birds are trying to catch‐up with the overall time‐schedule of migration for optimal arrival time on the breeding grounds. In contrast, birds with long distances remaining to breeding destinations were more likely to depart on the day of arrival and primarily used stopover to rest before quickly resuming migration, adopting similar strategies regardless of a bird's time‐schedule. Our study demonstrates that migrants adjust their en route strategies in relation to their time‐schedule and distance remaining to their breeding destination, highlighting that strategies of migration should be examined in the context of other phases of the annual cycle.     

Does migration promote or restrict circumpolar breeding ranges of arctic birds?

Aim Migration has been suggested to promote large breeding ranges among birds because of the greater mobility of migratory compared with non‐migratory species, but migration has also been suggested to restrict breeding ranges because of evolutionary constraints imposed by the genetically based migration control programme. We aim to investigate the association between migration and the breeding ranges of both land birds and pelagic birds breeding in the Arctic region. Location The Arctic region. Methods Information on breeding and wintering ranges and migratory status of bird species breeding in the arctic tundra biome was compiled from the literature. The association between breeding range, migration distance and primary winter habitat was tested using multivariate generalized linear models and pair‐wise Mann–Whitney U‐tests. Phylogenetic effects were tested for using Mantel’s permutation tests. Results We found different relationships depending on the species’ major winter habitat. Among birds that are pelagic during winter, long‐distance migrants have the largest breeding ranges, while among terrestrial birds, residents and short‐distance migrants have the largest breeding ranges. Breeding ranges of coastal birds of all migratory distance classes are comparatively restricted. Main conclusions As a new explanation for this pattern we suggest that the possibility of colonizing large winter ranges is a key factor for the subsequent expansion of breeding ranges in arctic bird communities and possibly also in bird communities of other regions of the world. Because of the reversal in the relative extent of continents and oceans between the hemispheres, longitudinally wide winter ranges are more likely for long‐distance than short‐distance migrants among pelagic birds, while the reverse holds true for birds that use terrestrial winter habitats. For coastal birds both continents and oceans form barriers restricting colonization of extensive winter quarters and consequently also of extensive breeding ranges, regardless of the distance to the winter quarters.     

Discovering the migration and non‐breeding areas of sand martins and house martins breeding in the Pannonian basin (central‐eastern Europe)

The central‐eastern European populations of sand martin and house martin have declined in the last decades. The drivers for this decline cannot be identified as long as the whereabouts of these long distance migrants remain unknown outside the breeding season. Ringing recoveries of sand martins from central‐eastern Europe are widely scattered in the Mediterranean basin and in Africa, suggesting various migration routes and a broad non‐breeding range. The European populations of house martins are assumed to be longitudinally separated across their non‐breeding range and thus narrow population‐specific non‐breeding areas are expected. By using geolocators, we identified for the first time, the migration routes and non‐breeding areas of sand martins (n = 4) and house martins (n = 5) breeding in central‐eastern Europe. In autumn, the Carpathian Bend and northern parts of the Balkan Peninsula serve as important pre‐migration areas for both species. All individuals crossed the Mediterranean Sea from Greece to Libya. Sand martins spent the non‐breeding season in northern Cameroon and the Lake Chad Basin, within less than a 700 km radius, while house martins were widely scattered in three distinct regions in central, eastern, and southern Africa. Thus, for both species, the expected strength of migratory connectivity could not be confirmed. House martins, but not sand martins, migrated about twice as fast in spring compared to autumn. The spring migration started with a net average speed of > 400 km d^–1 for sand martins, and > 800 km d^–1 for house martins. However, both species used several stopover sites for 0.5–4 d and were stationary for nearly half of their spring migration. Arrival at breeding grounds was mainly related to departure from the last sub‐Saharan non‐breeding site rather than distance, route, or stopovers. We assume a strong carry‐over effect on timing in spring.     

Cross‐continental migratory connectivity and spatiotemporal migratory patterns in the great reed warbler

Migratory connectivity describes to which degree different breeding populations have distinct (non‐overlapping) non‐breeding sites. Uncovering the level of migratory connectivity is crucial for effective conservation actions and for understanding of the evolution of local adaptations and migratory routes. Here we investigate migration patterns in a passerine bird, the great reed warbler Acrocephalus arundinaceus, over its wide Western Palearctic breeding range using geolocators from Spain, Sweden, Czech Republic, Bulgaria and Turkey. We found moderate migratory connectivity: a highly significant spatial structure in the connections between breeding and sub‐Saharan non‐breeding grounds, but at the same time a partial overlap between individual populations, particularly along the Gulf of Guinea where the majority of birds from the Spanish, Swedish and Czech populations spent their non‐breeding period. The post‐breeding migration routes were similar in direction and rather parallel for the five populations. Birds from Turkey showed the most distinctive migratory routes and sub‐Saharan non‐breeding range, with a post‐breeding migration to east Africa and, together with birds from Bulgaria, a previously unknown pre‐breeding migration over the Arabian Peninsula indicating counter‐clockwise loop migration. The distances between breeding and sub‐Saharan non‐breeding sites, as well as between first and final sub‐Saharan non‐breeding sites, differed among populations. However, the total speed of migration did not differ significantly between populations; neither during post‐breeding migration in autumn, nor pre‐breeding migration in spring. There was also no significant relationship between the total speed of migration and distance between breeding and non‐breeding sites (neither post‐ nor pre‐breeding) and, surprisingly, the total speed of migration generally did not differ significantly between post‐breeding and pre‐breeding migration. Future challenges include understanding whether non‐breeding environmental conditions may have influenced the differences in migratory patterns that we observed between populations, and to which extent non‐breeding habitat fluctuations and loss may affect population sizes of migrants.     

Migratory movements of waterfowl in Central Asia and avian influenza emergence: sporadic transmission of H5N1 from east to west

Waterfowl in the genera Anas and Tadorna are suspected as vectors in the long‐distance transmission of highly pathogenic avian influenza H5N1. The former Soviet Republics of Central Asia are situated at an important migratory crossroads for these and other species of birds that bridges regions where the disease is prevalent. However, waterfowl movements through Central Asia are poorly quantified. In this study, historical data derived from over 80 years of bird ringing are combined with recent satellite tracking data to delineate migration routes, movement chronology and habitat use patterns of waterfowl in relation to H5N1 outbreak locations. Results confirm migratory linkage between breeding and moulting areas in northern Kazakhstan and southern Siberia, with non‐breeding areas in the Caspian, Black and eastern Mediterranean Sea basins, as well as with South Asia. However, unlike the situation in neighbouring regions, most notably western China, H5N1 outbreaks have not been recurrent in Central Asia after they were first reported during summer 2005 and spring 2006. These findings have implications in relation to potential sampling biases, species‐specific variation in migratory behaviour and continuing regional H5N1 transmission risks.     

Individual variation in migratory movements and winter behaviour of Iberian Lesser Kestrels Falco naumanni revealed by geolocators

The population decline of the Lesser Kestrel Falco naumanni has been the subject of studies across its Western Palaearctic breeding range, but little is known about its use of pre‐migratory areas or African wintering quarters. We used geolocators to describe the temporal and spatial patterns of Portuguese Lesser Kestrel migration and wintering behaviour. Data on the complete migration were obtained from four individuals and another three provided further information. Prior to southward migration, Lesser Kestrels showed two different behaviours: northward‐orientated movements to Spain and movements in the proximity of the breeding area. Autumn migration took place mostly in late September; spring departures occurred mainly in the first half of February. Wintering grounds included Senegal, Mauritania and Mali, with individuals overlapping considerably in Senegal. Movements registered within the wintering grounds suggest itinerant behaviour in relation to local flushes of prey. During spring migration, birds crossed the Sahara Desert through Mauritania, Western Sahara and Morocco before passing over the Mediterranean to reach Portugal. Autumn migration lasted 4.8 ± 1.1 days, and spring migration lasted 4.1 ± 0.3 days. The mean daily flight range varied between approximately 300 and 850 km for an entire journey of around 2500 km. Effective protection of roosting sites in both pre‐migratory and wintering areas and maintaining grasshopper populations in Sahelian wintering quarters appear crucial in preserving this threatened migratory raptor across its African–Eurasian flyway. There was no evidence of any deleterious effects of fitting birds with loggers.     

Migratory movements and wintering areas of Leach's Storm‐Petrels tracked using geolocators

Accumulating evidence suggests that Atlantic populations of Leach's Storm‐Petrels (Oceanodroma leucorhoa) are experiencing significant declines. To better understand possible causes of these declines, we used geolocators to document movements of these small (～50‐g) pelagic seabirds during migration and the non‐breeding period. During 2012 and 2013, movement tracks were obtained from two birds that traveled in a clock‐wise direction from two breeding colonies in eastern Canada (Bon Portage Island, Nova Scotia, and Gull Island, Newfoundland) to winter in tropical waters. The bird from Bon Portage Island started its migration towards Cape Verde in October, arrived at its wintering area off the coast of eastern Brazil in January, and started migration back to Nova Scotia in April. The bird from Gull Island staged off Newfoundland in November and then again off Cape Verde in January before its geolocator stopped working. Movements of Leach's Storm‐Petrels in our study and those of several other procellariiforms during the non‐breeding period are likely facilitated by the prevailing easterly trade winds and the Antilles and Gulf Stream currents. Although staging and wintering areas used by Leach's Storm‐Petrels in our study were characterized by low productivity, the West Africa and northeastern Brazilian waters are actively used by fisheries and discards can attract Leach's Storm‐Petrels. Our results provide an initial step towards understanding movements of Leach's Storm‐Petrels during the non‐breeding period, but further tracking is required to confirm generality of their migratory routes, staging areas, and wintering ranges.