Merops Apiaster Research Articles

Орнітофауна лучних екосистем у прикордонних районах Львівщини та Волині

Meadow ecosystems comprise a significant part of the area of Ukraine, especially in its western regions. Those ecosystems are subjects of concern today because of the active agricultural use and droughts that also threatens the animal population of meadows, including birds. Studies of meadow bird species of western Ukraine are limited to atlases, which results in a lack of precise data. This work was part of an international project on the conservation of the great snipe Gallinago media and allowed us to collect valuable data on the abundance and occurrence of meadow bird species nearby to the Polish and Belarusian borders of Ukraine — territories that are commonly ignored by Ukrainian researchers. The surveys of meadow birds conducted near the Ukrainian-Polish border in 2020 have shown that the general state of the marshes is worse compared to 2019: even close to the Western Bug river, only deep oxbow lakes were wet or contained some water, but minor lakes and wetlands of the valley were found to be dry. In total, we observed 141 bird species belonging to 17 orders. Among them, 26 were common by abundance and frequency, such as the great egret Ardea alba, the white stork Ciconia ciconia, the common quail Coturnix coturnix, the corn crake Crex crex, the northern lapwing Vanellus vanellus, the common redshank Tringa totanus, the common cuckoo Cuculus canorus, the Eurasian skylark Alauda arvensis, the meadow pipit Anthus pratensis, the western yellow wagtail Motacilla flava, the sedge warbler Acrocephalus schoenobaenus, the marsh warbler A. palustris, the great reed warbler A. arundinaceus, the common whitethroat Sylvia communis, the whinchat Saxicola rubetra, the thrush nightingale Luscinia luscinia, the common linnet Linaria cannabina, the corn bunting Emberiza calandra, the common reed bunting E. schoeniclus, and 7 more species, which were observed frequently though are not typical marshland species. We have identified the species that can be used as indicators of parameters of marsh ecosystems such as grass height (corn crake, western yellow wagtail, and sedge warbler), moisture (common redshank, common cuckoo, and the sedge and great reed warblers), and habitat type (corn crake, European bee-eater Merops apiaster, sedge warbler, common reed, and corn buntings).

Copying nesting attempts in a new site may be the wrong choice. A case in the European Bee-eater (<em>Merops apiaster</em>)

Insistent nesting attempts by a group of European Beeeaters in a new site, a pebbly bank of the middle course of Trebbia River, northern Italy, mostly failed because of the unmovable pebbles encountered during tunnel excavation. The birds later nested in an artificial sand heap, with full success that time. Various considerations suggest that birds insisted in the unsuitable site because they copied the nesting activity of model conspecifics. Finding social attraction and “public information” from conspecifics in a place where no breeding attempt was previously made would allow disentangling social philopatry from spatial philopatry.

To Avifauna of Nature Landmark Area "Budanova Gora" (Saratov Region, Russia)

Information about nesting birds’ fauna of nature landmark of regional significance Area "Budanova Gora" is presented in this work. During 2011–2021 two cluster plots of protected area were explored: erosive outlier with surrounding steppe biotopes and gully-beam network of five ravines. We revealed dominating bird species and actualized information about rare bird species from Red Data Books of Saratov Region and Russia: Eagle Owl (Bubo bubo), Roller (Coracias garrulus), Turtle-dove (Streptopelia turtur). Changes in nesting avifauna were estimated for ten years research and in comparing with early published data. The second cluster plot is characterized by greatest variety of birds, because of sclerophilic species: Bee-Eater (Merops apiaster), Roller, Pied Wheatear (Oenanthe pleshanka), Hoopoe (Upupa epops).

On the distribution of European Bee-eater in the Chelyabinsk region

On the distribution of European Bee-eater in the Chelyabinsk region

Acoustic Monitoring of Diurnally Migrating European Bee-Eaters Agrees with Data Derived from Citizen Science

The use of Autonomous Recording Units (ARUs) for wildlife monitoring has increased in recent years. Acoustic monitoring has been used for a wide range of research topics, but it has rarely been used for monitoring wildlife migrations. In this work we evaluate the use of acoustic monitoring to characterise the diurnal migration pattern of a bird species, the European Bee-eater Merops apiaster. We set up 3–4 acoustic monitoring stations daily from 11 August to 21 September 2017 in north-eastern Spain, during post-breeding migration of the species. We used the Vocal Activity Rate (VAR), defined as the number of calls per unit time, as an index of Bee-eater abundance to describe the daily and seasonal migration pattern of the species. We also assessed the relationship between daily mean VAR estimated by ARUs, with citizen science data uploaded to the platform Ornitho.cat over a large spatial scale. According to mean VAR, intensity of migration increased weekly until the last week of August when it peaked, with species abundance decreasing to the lowest values in the study area by late September. A significantly higher number of calls was detected in the first and last hours of the day. Our results agree with previously published seasonal and daily migration patterns described for the species. VAR was significantly, positively correlated with the percentage of citizen science records of Bee-eater uploaded to complete checklists, used as an independent source to compare migration timing. Overall, our results, validated through citizen science data, show that acoustic monitoring can effectively provide complementary data for monitoring the bird migration of vocally active species. The use of ARUs may help to improve our understanding of migratory behaviour and be useful for a wide range of purposes.

Population- and age-specific patterns of haemosporidian assemblages and infection levels in European bee-eaters (Merops apiaster)

Amongst other factors, host behaviour critically determines the patterns with which blood parasites occur in wild host populations. In particular, migratory hosts that sequentially occupy distant sites within and across years are expected to show distinct patterns of blood parasitism depending on their population-specific schedules and whereabouts. Here, we monitored haemosporidian parasitism in two populations of European bee-eaters (Merops apiaster), breeding in Portugal and Germany, with fundamentally different spatiotemporal migration patterns and colonisation histories. We describe and compare the composition of their parasite fauna as well as host population-, age- and sex-specific patterns in the frequency and intensity of infections. We found haemosporidian prevalence to be higher in Portugal compared with Germany and the prevalence generally increased with host age in both populations. Bee-eaters breeding in Portugal and wintering in western Africa mostly hosted parasites of the genus Haemoproteus, while Plasmodium lineages prevailed in birds breeding in Germany and wintering in central Africa. We found 18 genetic lineages, of which nine uniquely occurred in Germany, three uniquely in Portugal and six occurred in both breeding populations. The infection intensities (= % infected per inspected erythrocytes) ranged from 0.002% up to maximally 2.5% in Portugal and 9.6% in Germany. The intensity was higher in Germany compared with Portugal, vastly varied between the parasite genera (Haemoproteus > Plasmodium), but also differed between lineages of the same genus. Our results suggest that populations from different parts of a host’s breeding range differ in prevalence and the composition of their haemosporidian assemblages, rather than in the intensity of their infections. Whether these patterns are mainly caused by differential habitat use throughout the annual cycle and/or the population-specific co-evolutionary backgrounds of a host species in range expansion remains to be elucidated.

Population- and age-specific patterns of haemosporidian assemblages and infection levels in European bee-eaters (Merops apiaster)

Population- and age-specific patterns of haemosporidian assemblages and infection levels in European bee-eaters (Merops apiaster)

Bird collisions with power lines in Nakhchivan Autonomous Republic

The article summarizes the results of research in four selected sites (observations) on the impact of surface power lines on bird death in the area of Nakhchivan Autonomous Republic in 2016-2017. Studies show that electrical wires have a major impact on bird death during the spring migration and nesting period. We determined that 225 individual of 27 species were killed by electric shock in selected areas, while 16 individuals belonging to 3 predator bird species were exposed to this threat. Two of these species are in the World Red List. The next plot with high mortality rate was the Cananbar well - Shikhmahmud plain (2 km), although we did not make a research here for the first two months. An average mortality rate of birds here were 2.72 individuals/km. The electric poles in the selected Nakhchivan - Shikhmahmud road (4 km) consisted mainly of wooden material and were sometimes replaced with reinforced concrete. We attribute the fact that the percentage of deaths in this area is lower than other stations because of the poles are more wooden. Among the dead birds some species belonging to the Red List of the World (Falco naumanni and Coracias garrulus). As we already mentioned, beside the overhead electric wires were mainly dangerous to Ciconia ciconia, Buteo rufinus and eagles. The dead and wounded species were recorded only one to four km from the electric line. Among the most common species exposed electric shocks were: Columba livia, Merops apiaster, Corvus frugilegus, Sturnus vulgaris and Passer domesticus. A total of 3,225 birds from 26 species were killed by the private electric shock during the study, four birds could not be identified (unknown species). When looking at the process from a landscape-species perspective, bird species - those most exposed to the electric wires are: less open, open space (loos); forest landscape (fl); residential areas (ra) and less grove areas (lga).

Developing and validating a nestling photographic aging guide for cavity-nesting birds: an example with the European Bee-eater (Merops apiaster)

BackgroundAccurate estimation of nestlings’ age is essential in avian demography studies as well as in population ecology and conservation. For example, it can be useful for synchronizing nest visits with events of particular interest, such as the age at which young can be safely ringed, or in choosing the best period to attain the most accurate calculation of laying or hatching dates.MethodsWe constructed a photographic guide for aging European Bee-eaters (Merops apiaster) nestlings to 3-day age classes and evaluated the aging method by performing a validation exercise with several observers with no previous experience in aging bee-eater nestlings.ResultsThe aging guide for bee-eater nestlings allowed estimating age to within 3 days with an average accuracy of 0.85. We found the optimal period for aging nestlings was between days 13‒18 (with accuracy between 0.94 and 0.99), during which the status of feather development was more easily distinguishable from the preceding and subsequent age classes. During the first 3 days after hatching, nestlings could also be aged with high accuracy (0.93). The small size of the nestling in relation to the eggs and the nestling’s inability to raise its head during these first days allowed for good discrimination from the subsequent age class. Between days 25 and 28, nestlings were correctly aged in only half of assignments (0.55 sensitivity) and nestlings belonging to class 7 (days 7‒9) were the least correctly identified (0.38 sensitivity). However, by visiting the nests at 12 days intervals it is possible to achieve the highest accuracy in age estimation with the smallest disturbance and logistic investment.ConclusionsThis study highlighted how indirect methods and a simple protocol can be established and employed to quickly estimate nestling age in cases where handling nestlings is challenging or impossible, while minimizing disturbance in and around the nest.

Space Use and Daily Movement Patterns of the European Bee-Eater Merops apiaster during Breeding and Post-Breeding

In July 2016, six European Bee-eaters Merops apiaster were tagged with radio transmitters in order to determine their space use during breeding and post-breeding. During breeding, home-range sizes were 2.0–5.5 km2 (95% kernel contour of minimum convex polygon, MCP95) and the median distance between position points and the nesting burrow was 0.20 km (Q1–Q3: 0.10–0.38 km). After Bee-eaters had fledged, adult birds increased their home range to 10.6–175.2 km2 (MCP95) and the median moving distance to the nesting burrow to 3.90 km (Q1–Q3: 1.83–5.25 km). In the last study week, two birds always flew together in larger flocks, while other tagged birds used other locations, this may indicate stable foraging groups of birds from different colonies. Space use was significantly influenced only by cloudiness during breeding and not by temperature or precipitation. In the early breeding season, only males stayed overnight in roosting trees; subsequently, both males and females stayed there. From about the end of the second week after hatching no adult birds were in the breeding colony at night. The results of this pilot study must however be verified with a broader-scaled study approach.

The discriminant power of biometrics for sex determination in European Bee-eaters Merops apiaster

ABSTRACT Capsule A combination of several biometric measures enables the reliable sexing of the European Bee-eater Merops apiaster, a species with subtle sex differences in plumage and morphometry. Aims To explore variation in biometrics and their suitability to discriminate sex in adult European Bee-eaters Merops apiaster. Methods We sampled populations of a long-distance migratory species with low sexual size dimorphism, the European Bee-eater Merops apiaster, from colonies in western Iberia (Portugal) and Central Europe (Germany) to investigate body size variation and derive population-specific and general sex discriminant functions. Results Overall, male Bee-eaters were larger than females while Bee-eaters from Germany and Portugal did not differ in size, except for primary length and tail length. The best single measurement to discriminate sex was wing length for Portuguese birds and tail tip length for German birds, as in the combined dataset. Multivariate discriminant functions of head-bill, wing and tail tip lengths provided the highest discriminant accuracy, discriminating sex for 91% of the birds from Portugal, 96% from Germany and 94% when using the combined dataset. Nonetheless, the discriminant accuracy remained high in the functions using only two variables for Portugal (head-bill and tail tip 91%, head-bill and wing 88%, wing and tail tip 88%), Germany (head-bill and tail tip 95%, wing and tail tip 97%) and in the combined dataset (head-bill and tail tip 92%, wing and tail tip 93%). Conclusions Population specific discriminant functions allow sexing of European Bee-eaters by morphometry with high degree of accuracy at least for Iberia and Central European populations. Such discriminant functions can be used to assign the sex of adult Bee-eaters reliably and swiftly while the bird is still in the hand, highlighting the potential of these functions for rapidly sexing species with low degrees of sexual size and plumage dimorphism.

FIRST RECORDS OF THE CHEWING LICE (PHTHIRAPTERA) ASSOCIATED WITH MEROPIDAE SPECIES IN BISKRA (NORTHERN SAHARA, ALGERIA)

Ponte Academic JournalApr 2020, Volume 76, Issue 4 FIRST RECORDS OF THE CHEWING LICE (PHTHIRAPTERA) ASSOCIATED WITH MEROPIDAE SPECIES IN BISKRA (NORTHERN SAHARA, ALGERIA)Author(s): TORKI Somia ,MARNICHE Faiza, DIK Bilal, GUEZOUL OmarJ. Ponte - Apr 2020 - Volume 76 - Issue 4 doi: 10.21506/j.ponte.2020.4.1 Abstract:Studies on Meropidae ectoparasites are scarcely reported in Algeria. This paper aims to provide an in-depth analysis of the ectoparasites of Merops apiaster and M. persicus. Beekeepers captured the bee-eaters used in this survey in April 2018 using glue to protect their hives. The captured individuals were transported to the laboratory to collect ectoparasites. The 4 bee-eaters examined were infested as follows: 2 with Merops apiaster and 2 with M. persicus. 3 species of the ectoparasites found on individuals belong to the Meropidae family, namely Meromenopon meropis, Meropoecus meropis and Meropsiella erythropteri. Download full text:Check if you have access through your login credentials or your institution Username Password

Development of the information system for forecasting collision between birds and wind farms

The information system for processing the results of observations of birds on the territory of a wind farm was created. The information system ensures the storage and processing of the monitoring results, conducting statistical analysis of data and obtaining the forecast of the possibility of a collision of birds with blades of wind plants. Mathematical model of forecasting makes it possible to perform calculations in the case of incomplete information about the parameters of a wind wheel. The paper considers as an example the environmental situation on the territory of wind farm Primorsk-1, which is located on the coast of the Sea of Azov. The information on 5923 registered birds of 45 species was processed. 72 birds of four species were identified in the dangerous zone of a collision of birds with rotor blades at the altitudes of 48 and 182 m: Larus ridibundus (43 birds), Merops apiaster (15 birds), Buteo buteo and Circus aeruginosus, respectively, 5 and 9 birds. Evaluation of risks of collisions was performed for one year of the wind park operation, taking into consideration the behavior of birds in different seasons of a year cycle (wintering, migration, and nesting). Based on the obtained data, the analysis of the possibility of the death of birds due to their collision with rotor blades was performed. The calculations were carried out using the model that was constructed according to the recommendations of the Fund Scottish natural heritage. The probability of collision of a bird while being in the rotor space slightly depends on its geometrical dimensions and is within 11–14 %. Prediction of the total number of collisions in calculation per one turbine a year is at the level of 0.07–0.25 birds. Almost half out of this number refers to Larus ridibundus. The total number of collisions of all birds within one year of the operation of a wind farm with 26 turbines is nearly 1.7–6.5 birds. The obtained data are consistent with the results of the studies of European researchers.

The Bee-eater (Merops apiaster) nesting in mountain areas

[The European Bee-eater (Merops apiaster), usually breeding in lower, warm latitudes up to July isotherm of 21°C (Cramp, 1985), has recently begun his expansion in northern Italy. Gregarious throughout the year, the European Bee-eater is a summer visitor in Europe. In 2017 a new breeding colony of four-five breeding pairs, has been found out in mountain habitat facing the plain at 1,250 meters a.s.l. in Italian western Alps, showing his expansion not only in northern latitudes but even in altitudinal environment].
 
 [Article in Italian]

Vocal activity rate index: a useful method to infer terrestrial bird abundance with acoustic monitoring

Autonomous recording units have been widely used in a large number of bird studies in recent years, but challenges remain in estimating abundance based on acoustic monitoring. We tested whether vocal activity rate index (VAR; the number of songs per unit time for a species), recorded using autonomous recording units, was related to population abundance in two terrestrial bird species, the European Bee‐eater Merops apiaster and the Dupont's Lark Chersophilus duponti. We took recordings at sites where censuses were also carried out to estimate local populations around recorders. We found a positive and significant relationship for the two monitored species. Although our results are not conclusive, the strong and significant relationship found for both monitored species suggests that VAR may be used to infer bird abundance around recorders in terrestrial species. We describe five logical steps for using the VAR with autonomous recording units in other species to guide future studies.

Pliocene Origin, Ice Ages and Postglacial Population Expansion Have Influenced a Panmictic Phylogeography of the European Bee-Eater Merops apiaster

Oscillations of periods with low and high temperatures during the Quaternary in the northern hemisphere have influenced the genetic composition of birds of the Palearctic. During the last glaciation, ending about 12,000 years ago, a wide area of the northern Palearctic was under lasting ice and, consequently, breeding sites for most bird species were not available. At the same time, a high diversity of habitats was accessible in the subtropical and tropical zones providing breeding grounds and refugia for birds. As a result of long-term climatic oscillations, the migration systems of birds developed. When populations of birds concentrated in refugia during ice ages, genetic differentiation and gene flow between populations from distinct areas was favored. In the present study, we explored the current genetic status of populations of the migratory European bee-eater. We included samples from the entire Palearctic-African distribution range and analyzed them via mitochondrial and nuclear DNA markers. DNA data indicated high genetic connectivity and panmixia between populations from Europe, Asia and Africa. Negative outcomes of Fu’s Fs and Tajima’s D tests point to recent expansion events of the European bee-eater. Speciation of Merops apiaster started during the Pliocene around three million years ago (Mya), with the establishment of haplotype lineages dated to the Middle Pleistocene period circa 0.7 Mya. M. apiaster, which breed in Southern Africa are not distinguished from their European counterparts, indicating a recent separation event. The diversification process of the European bee-eater was influenced by climatic variation during the late Tertiary and Quaternary. Bee-eaters must have repeatedly retracted to refugia in the Mediterranean and subtropical Africa and Asia during ice ages and expanded northwards during warm periods. These processes favored genetic differentiation and repeated lineage mixings, leading to a genetic panmixia, which we still observe today.

ОСОБЛИВОСТІ РЕЛЬЄФОУТВОРЮВАЛЬНОЇ ДІЯЛЬНОСТІ ОКРЕМИХ ПРЕДСТАВНИКІВ ОРНІТОФАУНИ УКРАЇНИ

Some types of birds in the course of their life create forms of the earth’s surface, which sometimes can be present on quite large territories. Most often these landforms have the rank of pico-, nano- and, more rarely, microrelief. Depending on the character of influence on the earth’s surface and existing relief, birds can perform the roles of “constructors”, “destructors”, “compilers” and “conveyors”. “Constructors” create accumulative biogenic relief forms, “destructors” take an active part in the formation of denudation relief forms, “compilers” participate in the accumulation of sediment, while “conveyors” take part in the relocation of sediment. As a result of their activities, two types of relief are formed, namely accumulative (formed by “constructors” and “compilers”) and denudation (created be “destructors”). Among the accumulative biogenic relief forms created by birds within the territory of Ukraine, there can be named mounds at the foot of steep slopes and hills within the nesting cells, created by sand martins and bee-eaters; nest cones of flamingos; nests of Eurasian coots, etc. As regards the denudation relief forms, burrowing nests of many birds can be specified. It should be mentioned, that the biogenic denudation relief forms created by birds (burrowing nests) are found in different parts of our country much more frequently than accumulative ones. In many cases, they form a porous surface of mural slopes, composed of friable material. The results of field research of biogenic relief forms within the territory of Ukraine give grounds to assert that the most extensive relief-forming activity among the birds within our state is done by European sand martins and European bee-eaters. Sand martins, which nest in large colonies up to 1.5 (sometimes even more) thousand pairs, in the course of their life, have a very significant influence on the earth’s surface and existing relief. They build their nests-burrows oh high steep shores of large bodies of water made of soft loose soil. More rarely, birds use quarry slopes, hills on the roadside or construction sites. The horizontally located hole is excavated at the top part of the precipice at a height of at least 1-1.5 m from its bottom. Its length ranges from 20 cm to 1 m, although sometimes it can reach 1.5 and even 2 m. The height of the entrance in the hole is 50-100 mm, and the width is 60-120 mm. The hole ends with a small extension (a nesting cell) the size of 80-120 mm × 100-120 mm. There is a litter composed of grass, straws, feathers and so on in the nesting cell. Its thickness in the central part can reach 2.5 cm. With height, the density of holes increases and their number can reach more than two dozen per 1 m². During the field research, the areas of slopes with holes of sand martins up to 1 km long were identified. The construction and functioning of nests provoke the emergence of the scree-forming process, which leads to the formation of screen cones. The height of individual cones can reach 1m. Bee-eaters also equip burrowing nests and form a porous surface of slopes. These birds nest in colonies ranging in numbers from several birds to several dozen or even hundreds of pairs. They mostly equip nests at a height of 3-5 m from the bottom of the precipice. For digging holes, bee-eaters prefer loam, although the soil does not play a large role. In a dense soil, the birds dig a hole with a short passage from 0.5 to 1 m, whereas in a loose soil it is built with a long passage, up to 1.5 (sometimes 2-3) m. The holes of bee-eaters are almost always horizontal and end with an extended nesting cell, which does not have a picohill in the middle. Biogenic relief forms within the territory of Ukraine are also created by common kingfishers, blue-cheeked bee-eaters, European rollers, rosy starlings, woodpeckers, Eurasian coots and flamingos, but the scale of their relief-forming activity influence on earth’s surface is considerably smaller in comparison with sand martins and bee-eaters.

Software for analyzing the probability of collisions of birds with rotors of wind electrical installations

The program "Birds" has been developed for analyzing the risks of bird collisions with turbines of wind power stations. The mathematical model of the program is based on the recommendations of the Scottish Natural Heritage Foundation. The source database contains the necessary information in relation to the operating conditions of the wind farm "Primorsk-1", which is supposed to be built on the coast of the Azov Sea in the Zaporizhia region. If necessary, the user can enter his own values and get results on the interaction of birds with wind turbine rotors on the following indicators: bird flight time through the rotor space, probability of collision of one individual with the turbine, depending on its flight characteristics and parameters of the wind electrical installation, number of bird collisions at a given time interval. The program was tested using the example of calculating the number of collisions of birds with rotors during one year of operation of the Primorsk-1 wind park. It is shown that the probability of a collision of one bird with the rotor depends little on its geometric dimensions and is in the range of 11-15%. The total number of collisions of all birds on the territory of the wind farm will be 6,4 birds, which corresponds to 0.25 individuals per turbine. Most of this amount (about 4.8) refers to two species: Merops apiaster and Larus ridibundus.

European bee-eaters (Merops apiaster) and apiculture: understanding their interactions and the usefulness of nonlethal techniques to prevent damage at apiaries

Finding a balance between wildlife conservation and land use protection when conflicts arise requires applying measures based on scientific knowledge and applicability. This is because of the complexity of interactions and the social dimensions of human–wildlife relationships. One of the conflicts in the Mediterranean basin is between European bee-eaters Merops apiaster and beekeeping. The objective of this study was to evaluate the activity of bee-eaters in relation to honey bees Apis mellifera in Extremadura (W Spain), and the possible correlation with traits and viability of beehives. We also aimed to assess the effectiveness of damage prevention measures, to be able to predict whether they could assist in the future sustainability of apicultural management. A monitoring program was conducted in 58 apiaries to observe bee and bee-eater activity and abundance. Additionally, we measured the effect of environmental variables and the amount of resources in the hives, by means of honey, pollen, and brood. We found that bee-eater negatively correlated to honey bee activity and the more abundant it was the fewer resources (honey, pollen, and brood) and lower abundance of bees in the hives, mainly during their migratory season (August). However, there were no negative effects on the survival and viability of the hives. The preventive and deterrent measures offered promising results, especially the installation of shading meshes around the apiary that prevented the predation of bees in the immediate surroundings of the beehives. Further studies on the effectiveness of preventive techniques and their practical implementation through different mechanisms of economic compensation must be enhanced to reduce this social conflict.

Spatiotemporal Group Dynamics in a Long-Distance Migratory Bird

Thousands of species migrate [1]. Though we have some understanding of where and when they travel, we still have very little insight into who migrates with whom and for how long. Group formation is pivotal in allowing individuals to interact, transfer information, and adapt to changing conditions [2]. Yet it is remarkably difficult to infer group membership in migrating animals without being able to directly observe them. Here, we use novel lightweight atmospheric pressure loggers to monitor group dynamics in a small migratory bird, the European bee-eater (Merops apiaster). We present the first evidence of a migratory bird flying together with non-kin of different ages and sexes at all stages of the life cycle. In fact, 49% stay together throughout the annual cycle, never separating longer than 5days at a time despite the ∼14,000-km journey. Of those that separated for longer, 89% reunited within less than a month with individuals they had previously spent time with, having flown up to 5,000km apart. These birds were not only using the same non-breeding sites, but also displayed coordinated foraging behaviors-these are unlikely to result from chance encounters in response to the same environmental conditions alone. Better understanding of migratory group dynamics, using the presented methods, could help improve our understanding of collective decision making during large-scale movements.