Ring Recoveries Research Articles

Seasonal migrations and morphometry of the European Nightjar according to long-term (1957–2016) trapping and ringing in the Eastern Baltic

The results of trapping, measuring the size and weight of the body of the European Nightjar, as well as migration routes according to the data of the ringing in the Kaliningrad region during 1957–2016 are discussed. The annual number of migrating birds has fluctuated significantly for 60 years, and the number of those caught and ringed varied from one to 44 individuals in different years. They were most numerous in May, in the period 1969–1981. Four ring recoveries of Nightjars ringed by us were obtained, which gives the effectiveness of ringing of this species with nocturnal activity of only 0.92%. However, these ringing results indicate that in autumn the migration routes of Nightjar population from the western parts of Scandinavia and from southern Finland run through the eastern coast of the Baltic Sea, and later, on the way to Africa, their azimuth of flight varies from 178° to 203°. The longevity record according to the data from one male of the subspecies Caprimulgus europaeus zarudny E. Hartert, 1912 was 15 years. The migration routes of this species are discussed according to the latest literature data.

Annual survival rates of satellite-tracked adult European honey buzzards (Pernis apivorus) based on the Kaplan-Meier estimator and its probabilistic extension

Abstract The annual survival rate of adult raptors is an important parameter in population dynamics and is needed to derive measures for population stability and conservation management. Here we studied adult European honey buzzards (Pernis apivorus), a migratory land bird, using satellite telemetry throughout the year for up to three years. We used the Kaplan-Meier method of survival estimation in combination with the distribution density function for survival. This function describes the number of survivors N as a function of time t, based on the survival rate SR. This probabilistic extension of the Kaplan-Meier estimator results in a simple method that does not require a commercial statistical program to extract survival rates from event time analysis. It can be applied to analysing any event-time data, not only telemetry results but also ring recoveries, as demonstrated using European honey buzzards as an example. The average adult survival rate in our study, based on permanent satellite telemetry monitoring, was 0.44/year (linear correlation factor f = 0.99). This implies an adult mortality rate of 0.56 per year. It seems that particularly unfavourable weather conditions during the crossing of the Sahara and the Mediterranean led to this high mortality rate of our birds during migration from 2001 to 2011, but is likely to vary greatly from year to year. However, the loss rate in the wintering area was also high, at one third of the birds. More honey buzzards need to be tracked throughout the year to assess factors affecting survival and threats to populations adequately.

From Siberia to Indonesia: tracking the migration of the Arctic Warbler Phylloscopus borealis

Little is known regarding the migration routes of Siberian songbird populations. Here we provide the first geolocator tracking data for an Arctic Warbler breeding in Central Siberia and compare its movements with eight long-distance ring recoveries of this species. In autumn, the tracked individual migrated eastward to a stopover site in eastern Siberia, before migrating southward through Taiwan to its non-breeding sites in the Philippines and Indonesia. During spring migration, the bird spent at least one month at stopover sites in Mongolia, before migrating to its breeding site in June. Ring recovery data confirmed the movement between the Central Siberian breeding grounds and stopover sites in northern Mongolia.

Coarse to Fine Two-Stage Approach to Robust Tensor Completion of Visual Data.

Tensor completion is the problem of estimating the missing values of high-order data from partially observed entries. Data corruption due to prevailing outliers poses major challenges to traditional tensor completion algorithms, which catalyzed the development of robust algorithms that alleviate the effect of outliers. However, existing robust methods largely presume that the corruption is sparse, which may not hold in practice. In this article, we develop a two-stage robust tensor completion approach to deal with tensor completion of visual data with a large amount of gross corruption. A novel coarse-to-fine framework is proposed which uses a global coarse completion result to guide a local patch refinement process. To efficiently mitigate the effect of a large number of outliers on tensor recovery, we develop a new M-estimator-based robust tensor ring recovery method which can adaptively identify the outliers and alleviate their negative effect in the optimization. The experimental results demonstrate the superior performance of the proposed approach over state-of-the-art robust algorithms for tensor completion.

Usage of ring-recovery data for the background for the Migration Atlas of the European Anseriform birds

The atlas was prepared from the data on ring-recovery database of the Bird Ringing Centre of Russia (Institute of Ecology and Evolution of the Russian Academy of Sciences). We plan to publish an extended version of the atlas on the base of bird ring-recovery data. The Atlas will consist not only description of the migratory routes but a consideration of several population parameters of the focal species, as well as, the spatial distribution characteristics of recoveries and even probable practical use of the obtained population parameters values. More than 42000 ring recoveries of 36 European waterfowl species were used. Besides the standard description of the migratory routes, monthly distribution of recoveries, maps of direct and indirect recoveries, etc., the Atlas contains some additional information. In particular, the population structure of species: geographical populations were revealed. It is known that these populations served as a basement of the flyway conception. Then we elaborated math model allows calculating mean yearly mortality rate for each species, in different periods, males and females, etc. Ring-recovery data of a number of species shows the influence of the global warming on the waterfowl. Wintering sites usually are permanent; however breeding places shift more and more to the north. Therefore, mean distance between wintering and breeding places progressively increasing during 20th and the beginning of the 21th century. In addition, the distribution of recoveries in relation to each other along the area was described: 1) it was possible to calculate the degree of aggregation of recoveries (aggregation) for the species with the most numerous recoveries, specifically – to calculate the mean distance from each recovery to its nearest neighbour (mean minimal distance between recoveries); 2) degree of recovery concentration in groups (concentration) with different number of recoveries that located at not more than some distance (might be called as “key distance”) from each other. The distance between recoveries within such groups is less than the distance between groups (clusters). The distribution of recoveries in connection with ecological capacities of the area where these recoveries are located is described for the first time. The distribution of recoveries by their proximity to the different waterbodies is compared: to small and big rivers, lakes, and to the seashore. The exploratory analysis of the separate and mutual numbers dynamics in the two systematically close waterfowl species was performed.

Age, brood fate, and territory quality affect nest-site fidelity in white stork Ciconia ciconia

BackgroundA particular type of site fidelity is faithfulness to the nest site, where birds are not only reoccupying breeding territories but also reusing nests built in previous breeding seasons. Staying faithful to the nest site is believed to be an adaptive strategy, and based on the ability to predict an individual's own breeding success, a hypothesis of “win-stay:loose-switch” was proposed. In this study, we aimed to resolve which factors affect the nest-site fidelity of white stork Ciconia ciconia, species known for reusing nests available in the breeding sites. Basing on ring recoveries from 31 years of studies in Western and Southern Poland, we analysed the impact of intrinsic and extrinsic factors on nest-site fidelity.ResultsWe found that increasing age and breeding success (i.e. producing any fledglings or not) increased the probability of reusing the nest, but in the oldest individuals, the probability decreased. In turn, the probability of breeding success increased with age, the increasing number of reproductive events on the particular nest, and the presence on the nest in the previous year. However, the oldest individuals had lower probability of success, as the relationship was curvilinear. The number of fledglings, however, was influenced only by an individual's age. The number of reproductive events on the nest was, in turn, affected by age, with the youngest and oldest individuals using the current nest for the least number of years.ConclusionsOur study shows that the decision process of whether to stay faithful to the nest or switch is based on the experience from the previous breeding event, consistently with the “win-stay:loose-switch” hypothesis. Our results also show that site fidelity benefits white storks, as the probability of breeding success increases if the nest is reused. Results also show the senescence effect that lowers breeding success and site fidelity probabilities.

Tracking wintering areas and post-breeding migration of a declining farmland bird – An indispensable basis for successful conservation

Many farmland birds, such as the Eurasian Curlew (Numenius arquata; here in after Curlew), are in steep decline. So far, decreased reproduction and, hence, an insufficient number of offspring to compensate for adult mortality has been considered the main driver of the recent population collapse. However, despite extensive conservation measures in most breeding areas, there are no signs of a general reversal of the population trend. Accordingly, conservation has to focus on decreasing adult mortality outside the breeding areas as well. For Curlews breeding in NW Germany, ring recoveries suggest that the main wintering areas are the coastlines of western France and southern England. However, such data are often biased in space and time. Here, we used GPS tracking to investigate the wintering areas and post-breeding migration of Curlews of the main German breeding population based on large sample size. Altogether, we tagged 86 adult breeding birds at 23 subareas across a transect of about 250 km (in length) in NW Germany. Curlews started post-breeding migration right after finishing breeding or attempting to breed, which was mainly in mid-June. We identified the coastlines of Great Britain/Ireland, western France and the Netherlands, in particular the Rhine-Meuse-Delta and the Wadden Sea, as the main wintering areas of Curlews breeding in NW Germany. We found a latitudinal structuration of migration, with birds nesting further north using more northerly wintering areas. However, in some cases, wintering areas of birds of the same subpopulation were located more than a thousand kilometres apart from each other. All three main stopover areas identified by our study (German/Dutch Wadden Sea, Dutch Rhine-Meuse-Delta, French Normandy) overlap in large parts with the main wintering areas. Since Curlews spend most of the year outside their breeding areas, and wintering and stopover areas also suffer from rapid environmental change, conservation has to additionally focus on these areas. Nearly one third (29%) of the tracked birds wintered in France or used French stopover areas. Accordingly, they might potentially be affected by a resumption of hunting, which is currently in discussion in France. Our study provides an important basis for the protection of wintering and stopover areas of the main German breeding population but also for other wader species migrating along the East Atlantic Flyway.

Non-breeding sites, loop migration and flight activity patterns over the annual cycle in the Lesser Grey Shrike Lanius minor from a north-western edge of its range

The Lesser Grey Shrike is a typical Palaearctic songbird for which we have limited knowledge of its migration ecology. All that is known about its non-breeding movements is inferred from observational data of birds on passage. The few available ring recovery data do not link breeding and African non-breeding grounds. By deploying two types of loggers, light-level geolocators and multi-sensor loggers, on birds from a declining Slovak breeding population, we present the first direct evidence for non-breeding grounds, loop migration, stopover sites and the timing of annual cycle events. With barometric data, we provide details on flight altitudes during migration. The two tracked birds migrated in a clear anti-clockwise loop to S Africa. Autumn migration tracks went through the Balkan Peninsula, Mediterranean Sea towards Libya with unusually long stays around N Chad and Niger. The next stopovers were in Angola, and the main non-breeding sites were in Botswana. Spring migration commenced on March 29 and April 7 and the birds took routes along East African countries, with stopovers later in Somalia and Saudi Arabia, before crossing the eastern Mediterranean Sea. Nocturnal migration dominated, but for three days in August, while crossing the Sahara Desert, the bird extended flights into the day with a sudden increase in flight altitudes at dawn. Flight altitudes were higher during barrier crossing and during the last phase of spring migration compared to the remaining periods, with the most extreme event recorded at 4530 m asl.

The northern hawk owl Surnia ulula invasions in Europe

Abstract The northern hawk owl is a real irruptive species that respond to irregular changes in the food supply. When prey levels are adequate, it breeds and winters within northern forests. Decreased prey availability can start winter invasions, the timing and magnitude of which are the subject of this study. Mainly the citizen data were extracted from the national bird websites to obtain data on the number of northern hawk owls observed in 2010–22. This paper demonstrates that through citizen data large amounts of information can be collected over wide areas, entire Europe in this case. From Finland to Poland and Czechia the invasions years were very similar, 2013–14, 2017–18 and 2021–22 but in Sweden and Norway three clear irruption years were a year or two before. In Denmark, the clear invasions years were 2013–14, 2016–17 and 2019–20 but Poland, peak years were not at all as clear as in the other countries. The invasions started earliest in Finland in September and peaked in November. In Estonia and Latvia peaks occurred from November to January. In Poland, irruption peaked a month later in December but continued until April like in Finland, Estonia and Latvia. The origin of the irrupting owls in the region has been debated. In Norway, authors are convinced that owls originate from Fennoscandia but this paper indicates that mass invasions have to originate from northern Russia. However, only in Denmark there was one Russian northern hawk owl ring recovery. Further ring recoveries and preferably GPS tagging and satellite tracking of the northern hawk owls are awaited to have a better picture of invasion movements and future conservation needs.

Are Roadkills Density-Dependent? Case Study of the Barn Owl (Tyto alba)

Even though birds are some of the most common road-killed animals, it remains to be determined whether avian roadkills are related to breeding numbers and breeding success, mainly due to a lack of study areas that monitor breeding populations and roadkills. We studied whether barn owl breeding numbers and breeding success are related to roadkills. We monitored yearly barn owl breeding numbers (2174 breeding attempts and 1682 adults ringed) and breeding success (9380 nestlings ringed) and monitored 95 km of roads weekly for roadkills from 2009 to 2017 in the Beit Shean and Emek Yizreel Valleys, Israel. During the study period, we documented 1073 road-killed barn owls, of which 328 were ring recoveries. The highest mortality occurred between July to September, coinciding with the barn owl post-fledging period. The number of breeding pairs and the number of nestlings ringed were positively related to the total number of barn owl roadkill, the proportion of roadkill ring recoveries, and the proportion of ring recovered roadkills in the first year of their life. First-year owls represent the majority of ringed owls, accounting for 64.6%, while adult owls compose 35.4%. Notably, a substantial fraction of adult ring recoveries, encompassing 67.2%, may pertain to floaters since we did not observe these individuals as breeding adults. Even though more females were found as roadkill ring recoveries, the proportion of male/female ring recoveries from roadkills was similar to that of adults ringed at the nest boxes. This study is the first that shows that barn owl roadkills are density-dependent and demonstrate the importance of monitoring breeding and population numbers in roadkill studies.

Современный статус балобана в России и в Казахстане

Современный статус балобана в России и в Казахстане

MIGRATORY CONNECTIONS IN WATERFOWL OF NORTHERN WESTERN SIBERIA, BASED ON RING-RECOVERY DATA

Migratory connections in waterfowl in the north of Western Siberia are discussed as based on ring recoveries from the database of the Bird Ringing Center of Russia, A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences. Altogether, 3531 recoveries from waterfowl of 29 species were used. The waterfowl in the region are characterized by exceptionally wide migratory connections, occurring in different seasons in most regions of the Old World within the Northern Hemisphere: from Iceland to the Japanese Islands and from West Africa to the Indian Subcontinent and the Yangtze River basin. The long-distance flights of birds to molting sites, the interannual change of nesting grounds and wintering regions, as well as the distribution on wintering grounds are discussed. Ten wintering regions have been allocated. The available material on the migration of waterfowl is evaluated from the viewpoint of completing the description of their seasonal distribution and its significance in the study of ecological connections of the territory of Western Siberia.

The Black Sea-Eastern Mediterranean flyway of the globally threatened European turtle dove (Streptopelia turtur)

The European turtle dove Streptopelia turtur (hereafter turtle dove), is a widespread species in the Palearctic. Due to a large and rapid decline in its abundance, it was classified as "vulnerable" on the International Union for Conservation of Nature's Red List in 2015 and is now regarded as a globally threatened species. The objective of this study was to provide new information on the flyways of this turtle dove population by analyzing available ring recoveries and citizen science sightings data from the Global Biodiversity Information Facility. A new flyway (possibly stretching through the Black and Caspian Seas, Turkey, the Middle East, and Egypt toward the Eastern Sahel) is suggested for turtle doves breeding in Northern and Eastern Europe.

Should I stay or should I fly? Migration phenology, individual-based migration decision and seasonal changes in foraging behaviour of Common Woodpigeons

Migration is used by many species as a strategy to deal with a seasonally changing environment. For some species, migration patterns can vary across different or even within the same breeding area. The Common Woodpigeon Columba palumbus, an abundant and widespread Palearctic species, exhibits three migratory strategies (strictly migratory, partially migratory and resident) across its European breeding grounds. Based on ring recoveries and satellite tracking data, we investigated the migration and foraging behaviour of Woodpigeons breeding in Southwestern Europe (Portugal) and Central Europe (Germany). We found that individuals could be classified as residents (Portugal) or partial migrants (Germany), with migrating individuals following the European sector of the East Atlantic flyway, and mainly wintering in France. In addition to general data on migration phenology, we provide evidence for different migration strategies (migration of varying distances or resident behaviour), low wintering site fidelity and the use of multiple wintering sites. Furthermore, tracking data provided information on migratory behaviour in consecutive years, clearly showing that individuals may switch migratory strategies (resident vs. migrant) between years, i.e. are facultative partial migrants. While individuals from Portugal mainly stayed within a large park (‘green urban area’) year-round, Woodpigeons from the city of Giessen (Germany) regularly left the urban area to forage on surrounding farmland (with an average distance covered of 5.7 km), particularly from July to September. Overall, our results highlight the behavioural plasticity in Woodpigeons in terms of foraging and migration strategies within and amongst individuals as well as populations.

Additions to ring resightings and recoveries of migratory shorebirds at Marine National Park and Sanctuary, Gujarat, India

Additions to ring resightings and recoveries of migratory shorebirds at Marine National Park and Sanctuary, Gujarat, India

Identifying the winter grounds of the recently described Barbary Reed Warbler (Acrocephalus baeticatus ambiguus)

The Iberian and North African populations of reed warblers have been described recently as a separate taxon, ambiguus, forming a sister clade to the Sahelian subspecies minor of African Reed Warbler Acrocephalus baeticatus. Although the breeding range of ambiguus has been identified, the migration strategy of its populations remained unknown. We deployed geolocators and sampled the innermost primary from breeding adults in Spain for stable hydrogen (δ2H) analyses and also analysed stable carbon (δ13C) and nitrogen (δ15N) isotopes in feathers collected in two reed warbler taxa (Acrocephalus scirpaceus and Acrocephalus baeticatus ambiguus) in Morocco, to identify the moulting and wintering sites of these populations. Ring recoveries, geolocator tracks and probabilistic assignments to origin from δ2H values indicate that Spanish ambiguus are likely to moult south of the Sahara and winter in West Africa, probably from Mauretania to southern Mali and Ivory Coast. Moroccan ambiguus, however, undergo post‐breeding moult north of the Sahara, and possibly then migrate to West Africa. With other populations of ambiguus breeding from Algeria to Libya and probably wintering further east in the Sahelian belt, the Barbary Reed Warbler can therefore be considered a trans‐Saharan migrant, with a post‐breeding moult strategy that varies between populations, and probably structured according to breeding latitude.

Diet of breeding Eleonora's falcon Falco eleonorae in Algeria: Insights for the autumn trans-Mediterranean avian migration.

How environmental changes are affecting bird population dynamics is one of the most challenging conservation issues. Dietary studies of top avian predators could offer scope to monitor anthropogenic drivers of ecosystem changes. We investigated the diet of breeding Eleonora's falcon in an area of Northeastern Algeria in the years 2010–2012. Feathers and insect remains originating from prey plucking behavior were analyzed, providing insights into the seasonally changing diet of this raptor, as well as the trans‐Mediterranean avian migration. A total of 77 species of birds (16 Sylviidae, 11 Turdidae, and 4 Emberizidae), 3 species of insects, and 1 lizard were identified among prey remains, reflecting a diverse diet. Diet composition and prey abundance varied seasonally, faithfully correlating with the passage of migrant birds as recorded from bird ring recoveries. Our findings suggest that dietary studies of predators might be deployed to investigate changes in bird migration. We discuss our results in the context of trans‐Mediterranean migration, with early‐season prey mainly comprising trans‐Saharan migrants (Apus apus and Merops apiaster) and late‐season prey being dominated by Mediterranean winter migrants (Erithacus rubecula, Turdus philomelos, Sylvia atricapilla, and Sturnus vulgaris). Notably, we observed a significant reduction in species richness of passerine remains in 2012, potentially highlighting a decline in the diversity of avian migrants.

Analysis of the Recovery Data of the Great Cormorant Phalacrocorax carbo Ringed in the Russian Federation and on the Territory of Former Soviet States in 1939–2014

This study is based on recoveries of c. 86,850 Great Cormorants ringed in the Russian Federation during 1939–2014. Data were obtained from the Bird Ringing Centre of Russia. During 1939 to 2014 a total of 1667 Cormorant recoveries (1.9%) were added to the ringing database. The majority of the recoveries were made in the Caspian Sea, Azov Sea, Black Sea, Baltic Sea and in Kazakhstan inland waterbodies, including the Aral Sea (seven recoveries), Lake Alakol (46), Lake Balkhash (28), Kapchagay Reservoir (10) and Lake Zaysan (5). Non-breeding birds (assuming breeding at age > 3 years) comprised 89% of ring recoveries from 1939 to 1974, 95% from 1975 to 1990 and 100% from 1991 to 2014. This study is the first to describe the migration patterns for this species on a continental scale. From Kaliningrad in the west to Vladivostok in the east seven mega clusters of waterbodies and wetlands exist where Cormorants breed and were ringed. Although showing some overlap, birds belonging to a certain cluster were recovered in distinct wintering areas, often more than 2000 km from the breeding areas and separated by high mountain ranges. The general migration pattern is discussed for four geographic regions. The occurrence of east–west migration patterns is briefly discussed and deserves further study as well as the role of high mountain ridges possibly shaping the movements between summer and winter areas.

Revealing different migration strategies in a Baltic Common Tern (Sterna hirundo) population with light-level geolocators

The Common Tern (Sterna hirundo) is one of Germany’s farthest migrating bird species. Ringing studies have shown the use of the East Atlantic flyway, and according to their main wintering areas at the western and southern African coasts, German and European Common Tern populations have been divided into two allohiemic groups. However, first ring recoveries of German Common Terns in Israel indicated that some of the birds breeding in eastern Germany cross central Europe and migrate along the eastern African coast. To investigate the migratory behavior of Common Terns from East Germany, we fitted 40 Common Terns breeding in a colony at the German Baltic coast with light-level geolocators. Twenty-four loggers with analyzable datasets could be retrieved, revealing two different migratory strategies within one population. Seventeen individuals (70.83%) used the eastern Atlantic flyway and spent the winter at the western African coast, the Gulf of Guinea and the southern African coast, while the other individuals (n = 7; 29.17%) crossed central Europe, migrated along the eastern African coast and overwintered in the Mozambique Channel and South African coast. We, therefore, suggest to add a third allohiemic group to complement the picture of European Common Tern migration. Moreover, our results provide new knowledge and open new questions, which can be used for future studies regarding the evolution of different migratory strategies and its consequences in relation to climate change.

Migration distance affects how closely Eurasian wigeons follow spring phenology during migration

BackgroundThe timing of migration for herbivorous migratory birds is thought to coincide with spring phenology as emerging vegetation supplies them with the resources to fuel migration, and, in species with a capital breeding strategy also provides individuals with energy for use on the breeding grounds. Individuals with very long migration distances might however have to trade off between utilising optimal conditions en route and reaching the breeding grounds early, potentially leading to them overtaking spring on the way. Here, we investigate whether migration distance affects how closely individually tracked Eurasian wigeons follow spring phenology during spring migration.MethodsWe captured wigeons in the Netherlands and Lithuania and tracked them throughout spring migration to identify staging sites and timing of arrival. Using temperature-derived indicators of spring phenology, we investigated how maximum longitude reached and migration distance affected how closely wigeons followed spring. We further estimated the impact of tagging on wigeon migration by comparing spring migratory timing between tracked individuals and ring recovery data sets.ResultsWigeons migrated to locations between 300 and 4000 km from the capture site, and migrated up to 1000 km in a single day. We found that wigeons migrating to more north-easterly locations followed spring phenology more closely, and increasingly so the greater distance they had covered during migration. Yet we also found that despite tags equalling only around 2% of individual’s body mass, individuals were on average 11–12 days slower than ring-marked individuals from the same general population.DiscussionOverall, our results suggest that migratory strategy can vary dependent on migration distance within species, and even within the same migratory corridor. Individual decisions thus depend not only on environmental cues, but potentially also trade-offs made during later life-history stages.