Sedge Warbler Research Articles

Investigations of the tick burden on passeriform, water-associated and predatory birds reveal new tick-host associations and habitat-related factors of tick infestation.

Previous studies on the tick infestation of birds in the Carpathian Basin focused on songbirds (Passeriformes). Thus, the primary aim of the present work was to extend the scope of previous studies, i.e. to include aquatic (water-associated) bird species in a similar context, especially considering that these birds are usually long-distance migrants. Between March 2021 and August 2023, 11,919 birds representing 126 species were checked for the presence of ticks. From 352 birds belonging to 40 species, 905 ixodid ticks were collected. Tick species were identified morphologically and/or molecularly. Ticks from avian hosts belonged to seven species: Ixodes ricinus (n = 448), I. frontalis (n = 31), I. festai (n = 2), I. arboricola (n = 36), I. lividus (n = 4), Haemaphysalis concinna (n = 382) and Dermacentor reticulatus (n = 2). Nymphs of I. ricinus occurred with a single activity peak around March-May, whereas its larvae typically infested birds in May, June or July. By contrast, H. concinna usually had its activity maximum during the summer (nymphs in June-July, larvae later in July-August). Interestingly, two ornithophilic species, I. frontalis and I. arboricola, were most active around winter months (between October and April). A significantly lower ratio of aquatic birds was found tick-infested than songbirds. Several new tick-host associations were revealed, including I. ricinus from Greylag Goose (Anser anser) and D. reticulatus from Great Egret (Ardea alba) and Sedge Warbler (Acrocephalus schoenobaenus). Ticks were collected for the first time in Europe from two species of predatory birds as well as from Little Bittern (Ixobrychus minutus). Bird species typically inhabiting reedbeds were most frequently infested with H. concinna, and most ticks localized at their throat, as opposed to forest-dwelling avian hosts, on which I. ricinus predominated and ticks were more evenly distributed. In the evaluated region, aquatic birds appear to be less important in tick dispersal than songbirds. However, newly revealed tick-host associations in this category attest to their hitherto neglected contribution. The results suggest that the habitat type will have significant impact not only on the species composition but also on the feeding location of ticks on birds.

Species-specific and age-related migration strategies of three Acrocephalus warblers along the eastern European–African flyway

The species-specific and age-related autumn migration strategies of the sedge, reed and great reed warbler were investigated at stopover sites between central Europe and north-eastern Africa during autumn. Adult reed warblers accumulated larger fat reserves than juveniles and consequently were able to cover longer distances from most stopover sites. Juvenile sedge warblers, on the other hand, left Europe with significantly larger fat reserves than adults as opposed to the populations migrating along the western route. Both juvenile and adult great reed warblers were potentially able to make long flights without refuelling from the northern part of the Mediterranean region onwards. It was the proximity of large ecological barriers that had the most prominent influence on the potential flight distances of adult and juvenile Acrocephalus warblers during their southward migration. In reed and sedge warblers, the differences in mean flight distances covered by adults and juveniles were the largest (ca. 600 km) just before the crossing of the Mediterranean Sea, but smaller (ca. 200 and 400 km, respectively) in front of the Sahara Desert. Juvenile and adult great reed warblers were potentially able to cover 1660 km from Turkey, which was also supported by very low numbers of individuals caught at the Egyptian ringing sites. The results of this study carried out in the key regions of the eastern European–African flyway documented that migration strategies differed between adults and juveniles of three long-distance migrant species, yet this variation depended on the migration stage and the proximity of natural ecological barriers.

Ornithological and molecular evidence of a reproducing Hyalomma rufipes population under continental climate in Europe.

Reports on adult Hyalomma ticks in certain regions of the Carpathian Basin date back to the 19th century. These ticks were thought to emerge from nymphs dropping from birds, then molting to adults. Although the role of migratory birds in carrying ticks of this genus is known from all parts of Europe, in most countries no contemporaneous multiregional surveillance of bird-associated ticks was reported which could allow the recognition of hotspots in this context. From 38 passeriform bird species 956 ixodid ticks were collected at seven locations in Hungary. Tick species were identified as Ixodes ricinus (n = 598), Ixodes frontalis (n = 18), Ixodes lividus (n = 6), Haemaphysalis concinna (n = 321), and D. reticulatus (n = 1). All 12 Hyalomma sp. ticks (11 engorged nymphs and 1 unengorged larva) were identified as H. rufipes based on three mitochondrial markers. This species was only found in the Transdanubian region and along its southeastern border. The Common Blackbird and the European Robin were the two main hosts of I. ricinus and I. frontalis, whereas H. concinna was almost exclusively collected form long-distance migrants. The predominant hosts of H. rufipes were reed-associated bird species, the Sedge Warbler and the Bearded Reedling, both in their nesting period. This study provides ornithological explanation for the regional, century-long presence of adult Hyalomma ticks under continental climate in the Transdanubian Region of the Carpathian Basin. More importantly, the autochthonous occurrence of a H. rufipes population was revealed for the first time in Europe, based on the following observations: (1) the bird species infested with H. rufipes are not known to migrate during their nesting period; (2) one larva was not yet engorged; (3) the larva and the nymphs must have belonged to different local generations; and (4) all H. rufipes found in the relevant location were identical in their haplotypes based on three maternally inherited mitochondrial markers, probably reflecting founder effect. This study also demonstrated regional and temporal differences in tick species carried by birds.

Fuel load and flight range estimation of migrating passerines in the western part of the Carpathian Basin during the autumn migration

Estimating fuel load and potential flight ranges of migrant passerines are basic issues in understanding bird migration strategies. Thirteen sub-Saharan and three pre-Saharan migrant passerine species were analysed in this study. The birds were captured at the Tömörd Bird Ringing Station in the western part of the Carpathian Basin. A general linear model with body mass as the dependent variable and fat score, muscle score and wing length as independent variables were used to estimate lean body mass (body mass without fuel deposits) and fuel load. In ten of the species studied, models considering interactions between factors fit the data better than the main-effect models. Body mass was positively correlated with the fat score in all species, with muscle score in ten species and wing length in 14 species. During autumn, fuel load tended to be larger in the sub-Saharan migrants, especially in four species which pass over the Mediterranean Sea, Common Nightingale (Luscinia megarhynchos), Icterine Warbler (Hippolais icterina), Garden Warbler (Sylvia borin) and Barred Warbler (Curruca nisoria). Nine sub-Saharan migrants, Marsh Warbler (Acrocephalus palustris), Sedge Warbler (A. schoenobaenus), Eurasian Reed Warbler (A. scirpaceus), European Pied Flycatcher (Ficedula hypoleuca), Spotted Flycatcher (Muscicapa striata), Wood Warbler (Phylloscopus sibilatrix), Willow Warbler (Ph. trochilus), Common Whitethroat (C. communis) and Lesser Whitethroat (C. curruca) had estimated flight ranges similar (<1300 km) to two pre-Saharans, European Robin (Erithacus rubecula) and Eurasian Blackap (S. atricapilla). The three short-distance migrants, including the Common Chiffchaff (Ph. collybita) with the shortest distance, had sufficient fuel load to reach their southern European wintering sites without needing to refuel at stopover sites.

Chewing lice of passerine birds in reed beds in Slovakia, with a special focus on Panurus biarmicus.

A total of 1185 passerine birds representing five species were examined for chewing lice in reed beds in southwestern Slovakia in spring (April) 2008, 2009 and 2016. Additional collecting focused only on chewing lice from Panurus biarmicus (Linnaeus, 1758) (Passeriformes: Panuridae) was carried out in spring (April), summer (July) and autumn (October) 2019. A total of 283 (24%) birds were parasitized by 10 species of chewing lice of four genera: Penenirmus, Menacanthus, Philopterus, and Brueelia. Most birds showed only very light (1-10 lice/host; 74%) to light infestations (11-20 lice/host; 16%). The authors found significantly higher prevalences and mean abundances of chewing lice on residents/short-distance migrants, that is, P. biarmicus, Acrocephalus melanopogon (Temminck, 1823) (Passeriformes: Acrocephalidae), than on long-distance migratory birds, that is, Acrocephalus scirpaceus (Hermann, 1804), Acrocephalus schoenobaenus (Linnaeus, 1758) (Passeriformes: Acrocephalidae), Locustella luscinioides (Savi, 1824) (Passeriformes: Locustellidae). No significant difference was found in the total mean intensity of chewing lice between these two groups of birds. Ischnoceran lice were more prevalent and abundant than amblyceran lice on residents and short-distance migrants, whereas the opposite was found on bird species that migrate long distances. A total of 146 (58%, n=251) P. biarmicus were parasitized by 1490 chewing lice. Males of P. biarmicus showed higher prevalence and mean abundance than females with gradually descending values of prevalence, mean abundance and mean intensity from spring to autumn. The knowledge of the occurrence and population dynamics of lice on wild passerine birds can be useful in endangered species conservation programs and can also be applied to captive passerine birds, which may be analogous to resident birds in this sense.

Interactive effects of arrival date, territory quality and male polyterritorial behaviour on the mating system of the sedge warbler Acrocephalus schoenobaenus: a path analysis

Classical models predict that male fitness is based on resources monopolized and invested in reproduction, and/or on individual quality providing offspring with sexually attractive traits or viable genes. However, these factors are frequently correlated, making their relative influence on male fitness difficult to describe and quantify. We analysed the relative influence of the main features of the sedge warbler's Acrocephalus schoenobaenus breeding system, i.e. age, arrival date, territory quality, male sexual activity (song and polyterritorial behaviour), on males' mating success, fledging success and local recruitment. Results show that this species' breeding system involves three main paths: 1) earlier‐arriving males have higher mating success, regardless of territory quality, 2) the quality of territories pre‐empted by earlier males directly influences recruitment and 3) mating success is influenced by male sexual activity (polyterritorial behaviour), but an additional territory also affects recruitment directly. As arrival date plays a significant role in all the paths, the whole system seems to depend on male quality; although the benefits accruing to male fitness are obtained not only through sexual selection but also through resource monopolization.

Blood Metabolites and Profiling Stored Adipose Tissue Reveal the Differential Migratory Strategies of Eurasian Reed and Sedge Warblers

The overall speed of bird migration is limited by the amount of fuel stores acquired during the initial phases of migration. The ability to mobilize fat is crucial for migratory birds that can exhibit different migratory strategies. Birds mobilize triglycerides during nocturnal flight thus increasing circulating fatty acids and glycerol to meet the metabolic demands of flight. Eurasian Reed (Acrocephalus scirpaceus) and Sedge (Acrocephalus schoenobaenus) Warblers were captured at Portuguese stopover sites during spring and autumn migration. These species were selected based on their different migration strategies and dietary preferences during migration. Blood metabolites and fat composition were analyzed to determine their nutritional states. Sedge Warblers had higher blood triglyceride and glycerol levels during post-flight fasting than in non-fasting periods. Furthermore, Sedge Warblers had higher triglyceride and glycerol levels than Eurasian Reed Warblers in both post-flight fasting and non-fasting condition. The differences found may reflect distinct approaches in re-feeding activity (e.g., feeding intensely) associated with the number of stopovers during migratory cycle. Dietary preferences affect the fat composition available for oxidation during long-term exercise in migratory flight. Nuclear magnetic resonance analysis of subcutaneous fat composition revealed that Sedge Warblers presented higher levels of polyunsaturated fatty acid levels than Eurasian Reed Warblers. The distinct lipidic profiles observed and differences in feeding ecology may explain the different migration strategies of these species. Overall and despite their ecological similarity, our study species showed pronounced differences in blood metabolites levels and subcutaneous fatty acids composition, likely attributed to the migratory strategy and foraging preferences during their migratory cycle.

When to depart from a stopover site? Time since arrival matters more than current weather conditions

AbstractOn the journey to wintering sites, most migratory birds alternate between flights and stopovers, where they rest and refuel. In contrast to the time-minimization strategy commonly assumed to drive the pre-breeding migration, birds are rather expected to follow an energy minimization during post-breeding migration. It is the cumulative duration of flights and stopovers that determines the total energy requirements and duration of the journey. Since migrating birds actually spend most of the time at stopovers sites, selection to minimize the amount of energy or time spent on migration is likely to operate on the effectiveness of stopover rest and refueling. Here, we address the relative contribution of factors acting on departure decisions from a stopover site during the post-breeding migration in a long-distance migratory songbird. When capture probability is low, it is impossible to measure fattening over the entire duration of the stopover. To get around this limitation, we use time since arrival (TSA) as a proxy for the progressive temporal change occurring in the internal state of an individual (i.e. rest, physiological recovery, and fuel loading) during the stopover. We develop a capture–recapture model to address the respective effects of estimated TSA and of weather conditions on departure probability. Using a 20-year dataset for Sedge Warblers (Acrocephalus schoenobaenus), we show that TSA served as a surrogate of the most important information that birds use when deciding to depart from a stopover site, while low humidity and rising atmospheric pressure only slightly increase daily departure probability. Hence, a bird would resume migration mainly according to the time it had to rest and refuel, and then fine-tuning departure decision according to weather conditions. The generality of these results needs to be assessed by applying this modeling framework to other migratory species and at sites or times with greater weather variability.

Vocal learning in animals and humans.

Vocal learning in animals and humans.

Differences in a Cage Escape Behaviour between Two Migrating Warblers of Different Stop-Over Strategy.

Simple SummaryCognitive abilities play an important role for migratory birds that are briefly visiting a variety of unfamiliar stop-over habitats. Here, we compared cognitive abilities-linked behaviour (escape from an experimental cage) between two long-distant migrants differing in refuelling strategy during autumn migration, Sedge Warbler (not territorial, searching for locally superabundant food) and Reed Warbler (territorial, foraging on a common prey). We performed a cage experiment on individuals captured in mist-nets. After two minutes of acclimatization in the cage, we remotely opened the cage door and recorded the bird’s reaction. We measured latency that individuals needed to escape from a cage. Sedge warblers were more likely to escape from the cage than Reed Warblers. Sedge warblers generally escaped earlier after the door was opened and were more likely to escape at any given time than Reed Warblers. We interpret the prevalence of non-escaped individuals as a general feature of migratory birds. In contrast to resident species, they are more likely to enter an unfamiliar environment, but they are less explorative. Differences in escape latency between the studied species may be linked to various refuelling strategies in the context of specialist-generalist foraging. Our study provides ecological insight into the cognitive abilities-linked behaviour of wild animals.Cognitive abilities play an important role for migratory birds that are briefly visiting a variety of unfamiliar stop-over habitats. Here, we compared cognitive abilities-linked behaviour (escape from an experimental cage) between two long-distant migrants differing in stop-over ecology, Sedge Warbler (Acrocephalus schoenobaenus; not territorial, searching for locally superabundant food) and Reed Warbler (A. scirpaceus; territorial, foraging on a common prey) during the autumn migration. After two minutes of acclimatization in the cage, we remotely opened the cage door and recorded the bird’s reaction. We measured latency that individuals needed to escape from a cage. Sedge warblers were 1.61 times more likely to escape from the cage than Reed Warblers. Sedge warblers generally escaped earlier after the door was opened and were 1.79 times more likely to escape at any given time than Reed Warblers. We interpret the prevalence of non-escaped individuals as a general feature of migratory birds. In contrast to resident species, they are more likely to enter an unfamiliar environment, but they are less explorative. We attributed inter-species differences in escape latency to species-specific autumn stop-over refuelling strategies in the context of specialist-generalist foraging. Our study provides ecological insight into the cognitive abilities-linked behaviour of wild animals.

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).

Development of Trypanosoma everetti in Culicoides biting midges

Trypanosoma species (Trypanosomatida, Kinetoplastea) are almost exclusively heteroxenous flagellated parasites, which have been extensively studied as the causative agents of severe trypanosomiasis in humans and domestic animals. However, the biology of avian trypanosomes remains insufficiently known, particularly in wildlife, despite information that some species might be pathogenic and affect the fitness of intensively infected individuals. Avian trypanosomes are cosmopolitans. Due to regular bird seasonal migrations, this host–parasite system might provide new insight for better understanding mechanisms of transcontinental dispersal of pathogens, their ecological plasticity, specificity and speciation. Trypanosoma everetti parasitizes numerous bird species globally, but data on its biology are scarce and its vectors remain unknown. This study aimed to test experimentally whether widespread Culicoides (Diptera: Ceratopogonidae) biting midges are susceptible to infection with this parasite. Two common house martins Delichon urbicum and two sedge warblers Acrocephalus schoenobaenus naturally infected with T. everetti were caught in the wild after arrival from African wintering grounds. Laboratory reared Culicoides nubeculosus and wild-caught Culicoides impunctatus biting midges were exposed by allowing them to take infected blood meals. The experimentally infected and control insects were maintained in the laboratory and dissected at intervals to follow the development of the parasite. Infections were determined using microscopic examination and PCR-based testing. Four closely related haplotypes of T. everetti were found, and each was present in different individual parasite-donor birds. These parasites readily developed and produced metacyclic trypomastigotes in C. nubeculosus and C. impunctatus biting midges. Molecular characterisation of T. everetti was developed. According to Bayesian phylogenetic analysis using a DNA fragment encoding 18S rRNA, the five species of small avian trypanosomes were closely related. Wild caught Culicoides biting midges were also collected and screened for the presence of natural infections. In all, 6.8% of wild-caught biting midges belonging to five Culicoides species were PCR-positive for kinetoplastids, including Trypanosoma species. Culicoides biting midges are readily susceptible and likely naturally transmit avian trypanosomes and thus, should be targeted in epidemiology research of avian trypanosomiasis.

No Evidence for an Effect of Vegetation Productivity on the Structure and Diversity of a Reed-Bed Associated Passerine Assemblage during Autumn Migration

The structure of a species assemblage at given sites constitutes a key ecological parameter to understand the dynamics of bird assemblages. The aim of this paper is to (1) quantify how variable is a passerine assemblage associated with an inter-tidal reedbed area at a main stopover site in the Atlantic flyway in northern Iberia and to explore potential factors explaining the variation, with emphasis on the vegetation productivity, and (2) to test whether inter-annual fluctuations reflect possible demographic trends. Migratory birds, especially those species which show high flexibility to stop over in some places or others using an opportunistic strategy, should be expected to land in larger numbers and stay for longer periods at given stopover sites in years with higher vegetation productivity, thus with a higher amount of insect prey, since this would permit achieving higher fuel deposition rates. We used ringing data collected at Txingudi marshlands during the autumn migration of 2007–2016. The assemblage had a relatively simple structure, because few species dominated in number over the rest. Reed Warblers Acrocephalus scirpaceus dominated the assemblage in nine out of ten study years, supporting the importance of the site for the species. As compared with the other two most abundant passerines (the Sedge and Willow Warblers, A. schoenobaenus and Phylloscopus trochilus, respectively), the ratio between these three warblers varied from year to year, with the Willow Warblers having much higher annual fluctuations than the other two species. This is likely linked to an opportunistic exploitation of the reed bed by this species, but we did not find significant effect of vegetation productivity (quantified by Normalized Difference Vegetation Index, NDVI) on the structure and diversity of the bird assemblage. Annual fluctuations in species' contribution to the assemblage did not vary linearly, except for the Bluethroat Luscinia svecica. Only for Bluethroats the proportion of captures and the mean number of captures declined from year to year. The structure and diversity of the assemblage did not seem to be affected by local conditions hence factors working at larger spatial scales or at the origin region of the migrants captured at Txingudi apparently may be more relevant at explaining the structural traits of the assemblage.

The role of peri-urban wetland and meadow habitats in the protection of trans-Saharan migrant passerine species in a central European city

Densities were estimated for several passerine longdistance migrant species associated with peri-urban wetlands and meadows in the city of Wroclaw (293 km2), SW Poland. Acrocephalus arundinaceus, A. scirpaceus, Locustella naevia and Lanius collurio nested in a crude density of more than 0.2 pairs/territorial males per 100 ha. The group of four other species (Saxicola torquatus, Locustella fluviatilis, L. luscinioides and Acrocephalus schoenobaenus) bred in a crude density between 1.1 and 1.5 pairs per 10 km2. The least numerous were the Sylvia nisoria (0.06 pairs per 100 ha) and Remiz pendulinus (0.02 pairs per 100 ha). Most of these species nested in the city in higher crude density than in a neighbouring rural area, richer of suitable habitats. Most breeding pairs occupied extensive peri-urban wetlands and meadows. These habitats could play an important role in conservation of these trans-Saharan migrants, as well as other water and marshland bird species. Such habitats are postulated to be protected as nature reserves or Special Protection Areas of the Natura 2000.

Estimation of Local Heading Patterns of Nocturnal Migrants using Orientation Cages

Abstract Busse P. 2018. Estimation of local heading patterns of nocturnal Migrants using orientation cages. Ring 40: 31-58 The main aim of this paper is to compare the results of two data evaluation procedures used for presenting the data from the orientation cage field tests. Both procedures accept multimodality of the data and multimodality of the headings of an individual bird as well as migrating population. The goal is to reach acceptable level of migration patterns presentation in biological sense, taking under consideration a flexibility of the real movements, depending on specific weather and landscape parameters. Such knowledge is absolutely necessary for estimating migration bottle-necks and the long-term studies on influence of the climate changes on migration patterns. The material used for the comparison of the procedures was collected in years 2001-2007 by the team of the Bulgarian Ringing Station Kalimok (44°00’N, 26°26’E) within the frame of the SEEN (SE European Bird Migration Network) activity and kindly shared for evaluation. The data were obtained using the standard SEEN methods, with the standard Busse’s cage working procedure of the field tests. The material contains data on four species of nocturnal migrants living in different habitats: the Great Reed Warbler, Acrocephalus arundinaceus (ACR.ARU), the Sedge Warbler, A. schoenobaenus (ACR.ENO), the Willow Warbler, Phylloscopus trochilus (PHY.LUS) and the Whitethroat, Sylvia communis (SYL.COM). There are confirmed earlier conclusions that so called „classic” unimodal procedure is not applicable to the orientation cage data resulted from any field procedure. There are available two evaluation procedures that base on the same general assumptions: multimodality of distributions that reflects combination of several unimodal partial distributions, that can be described both using sophisticated Bayesian „Calculation” method and much simpler „Estimation” procedure. Results of both procedures are enough close to each other that they can be used for describing local and general heading patterns of migration of the nocturnal migratory movements studied using orientation cages.

Fuelling strategies differ among juvenile Sedge and Reed Warblers along the eastern European flyway during autumn migration

In this study, we investigated fattening strategies of juvenile Sedge and Reed Warblers during their autumn migration. We analysed fat scores of birds captured at five ringing sites situated between the southern Baltic Sea coast and Asia Minor. In Eastern Europe these two species had similarly low fat reserves. Their fat load increased in the Balkans. Remarkable differences between the species were noted in Asia Minor, where fat reserves of Sedge Warblers were more than two-fold higher compared to Reed Warblers. As high as 90% of Sedge and only 30% of Reed Warblers captured in Asia Minor had the potential capability to cross the Mediterranean Sea in one non-stop flight. Moreover, two-thirds of those Sedge Warblers were able to continue their long flight without refuelling and reach the southern edge of the Sahara desert, while in Reed Warblers only 6% of individuals were potentially able to use the same strategy. The results of the study show clear differences in potential flight ranges of the studied species, revealing different fattening strategies of the Sedge and Reed Warbler in the Balkans and Asia Minor.

Blood parasites shape extreme major histocompatibility complex diversity in a migratory passerine.

Pathogens are one of the main forces driving the evolution and maintenance of the highly polymorphic genes of the vertebrate major histocompatibility complex (MHC). Although MHC proteins are crucial in pathogen recognition, it is still poorly understood how pathogen-mediated selection promotes and maintains MHC diversity, and especially so in host species with highly duplicated MHC genes. Sedge warblers (Acrocephalus schoenobaenus) have highly duplicated MHC genes, and using data from high-throughput MHC genotyping, we were able to investigate to what extent avian malaria parasites explain temporal MHC class I supertype fluctuations in a long-term study population. We investigated infection status and infection intensities of two different strains of Haemoproteus, that is avian malaria parasites that are known to have significant fitness consequences in sedge warblers. We found that prevalence of avian malaria in carriers of specific MHC class I supertypes was a significant predictor of their frequency changes between years. This finding suggests that avian malaria infections partly drive the temporal fluctuations of the MHC class I supertypes. Furthermore, we found that individuals with a large number of different supertypes had higher resistance to avian malaria, but there was no evidence for an optimal MHC class I diversity. Thus, the two studied malaria parasite strains appear to select for a high MHC class I supertype diversity. Such selection may explain the maintenance of the extremely high number of MHC class I gene copies in sedge warblers and possibly also in other passerines where avian malaria is a common disease.

Busse’s flat orientation cage vs. Emlen’s funnel – compatibility, differences and conclusions

Abstract This paper focuses on field practice using different types of orientation cages. The two orientation cage designs most commonly used in field work, i.e. Emlen’s funnel and Busse’s flat orientation cage, are described in detail and compared for compatibility of results, simplicity of use and time effectiveness. Apart from cage designs and field procedures (60-min nocturnal tests in Emlen’s funnel vs. 10-min diurnal tests according to Busse’s procedure), the standard data evaluation procedures are compared and discussed. The data used in the discussion were collected for four species of nocturnal migrants (the Reed Warbler, the Sedge Warbler, the Willow Warbler and the Whitethroat) at the Kalimok Bird Station (Bulgaria): altogether 141 individuals were tested in Emlen’s funnel in 2001 and 788 in Busse’s cage in 2001-2007. The following conclusions were drawn: (1) Busse’s flat cage design and its standard procedures yield results fully compatible with those obtained using Emlen’s funnel and the associated procedures; this means full compatibility in terms of the directionality of tested birds in the diurnal and nocturnal tests; (2) the procedures compared have distinct differences in terms of constraints on the methods: – Emlen’s cage is extremely stressful for the bird and should be avoided as much as possible in practice due to animal welfare concerns; – Emlen’s standard procedure of testing the bird for 60 minutes is completely useless, as this is inefficient in terms of quality of results and causes more stress to the bird than is necessary; – Busse’s 10-minute standard makes it possible to collect a vast amount of data (12 birds per hour and person) in real field work, even performed in wilderness areas; (3) At the stage of evaluation of raw data it is essential to use evaluation tools which take into account the fact that raw data items show a high percentage of multimodal distributions, and therefore tools assuming unimodal distribution are unsuitable.

Diet Analysis of Wetland Passerine Nestlings Using Neck Collars or Faecal Sampling Produces Similar Results

Two methods are commonly used to study the diet of nestling passerines: the neck collar method and faecal sampling. Most studies apply either method, however, few methodological studies comparing both methods exist and are mainly limited to farmland birds. Furthermore, existing methodological studies only include high-level taxonomic diet categories. Here, we compared both methods using two wetland species, the Reed Bunting Emberiza schoeniclus and the Sedge Warbler Acrocephalus schoenobaenus, and included family level as a lower taxonomic prey level. We found no differences between the two methods in the dietary composition of high-level taxonomic categories (mainly orders) and only small differences in some orders at the family level. Hence, we recommend using the less invasive and easily accessible faecal sampling method rather than the use of neck collars in diet composition studies.

Chewing lice from wild birds in northern Greece

Greece represents an important area for wild birds due to its geographical position and habitat diversity. Although the bird species in Greece are well recorded, the information about the chewing lice that infest them is practically non-existent. Thus, the aim of the present study was to record the species of lice infesting wild birds in northern Greece and furthermore, to associate the infestation prevalence with factors such as the age, sex, migration and social behaviour of the host as well as the time of the year. In total 729 birds, (belonging to 9 orders, 32 families and 68 species) were examined in 7 localities of northern Greece, during 9 ringing sessions from June 2013 until October 2015. Eighty (11%) of the birds were found to be infested with lice. In 31 different bird species, 560 specimens of lice, belonging to 33 species were recorded. Mixed infestations were recorded in 11 cases where birds were infested with 2–3 different lice species. Four new host-parasite associations were recorded i.e. Menacanthus curuccae from Acrocephalus melanopogon, Menacanthus agilis from Cettia cetti, Myrsidea sp. from Acrocephalus schoenobaenus, and Philopretus citrinellae from Spinus spinus. Moreover, Menacanthus sinuatus was detected on Poecile lugubris, rendering this report the first record of louse infestation in this bird species. The statistical analysis of the data collected showed no association between parasitological parameters (prevalence, mean and median intensity and mean abundance) in two different periods of the year (breeding vs post-breeding season). However, there was a statistically significant difference in the prevalence of infestation between a) migrating and sedentary passerine birds (7.4% vs 13.2%), b) colonial and territorial birds (54.5% vs 9.6%), and c) female and male birds in breeding period (2.6% vs 15.6%).