Understanding how birds use stopover areas is essential for the effective conservation of migratory bird populations. Here, we evaluate the role of high-altitude grasslands in the Central-Eastern Pyrenees as autumn stopover habitat for the Iberian population of the Red-backed Shrike Lanius collurio. Using data from a standardized mist-netting program (2010–2024), we analysed age-related patterns in abundance, fuel load, fuel deposition rate and stopover duration. First-year birds were captured much more often (91.5%) and they did not have a longer stopover duration than adults. However, both age classes had a low mean fuel load (0.0338 ± 0.0536 SD, i.e. 3.4%) and a minimal fuel deposition rate, suggesting that the Pyrenees might not serve as a main refuelling site. Instead, the region may function as a transient area for the shrikes, particularly for first-year birds at the onset of their first migration. Despite the low fat accumulation, the high number of individuals using this area highlights its potential relevance. The mosaic of pastures and open habitats aligns with the shrikes' foraging preferences and may support a migration strategy based on short-distance flights with low energy reserves. Given the ongoing population decline and habitat loss, preserving these herbaceous areas is critical to ensure safe passage for species like the Red-backed Shrike. Our findings underscore the need to protect not only key fuelling sites but also early-phase resting habitats along migratory flyways.

We report a sighting of the Red-backed Shrike, a vagrant to peninsular India, from the coastal habitats of Thoothukudi (Tuticorin) District, Tamil Nadu. This observation is the second photographic record of the species for the state.

Abstract Avian brood parasitism is a widespread reproductive strategy in which parasitic birds exploit host nests to raise their offspring, often at a significant cost to the host species. Hosts counter parasitism through various defensive mechanisms, including egg rejection, which the either the visual presence or the vocalisations of the parasite near the nest can trigger. This study aimed to assess the response of Red-backed Shrikes ( Lanius collurio ), a species formerly commonly parasitised by the Common Cuckoo ( Cuculus canorus ) to simulated brood parasitism based solely on auditory cues, using playbacks of cuckoo vocalisations. Over two breeding seasons in eastern Poland, artificial Cuckoo eggs were placed in 63 Shrike nests, followed by playback experiments. The results revealed no significant effect of simulated parasite presence on egg rejection rates, and the playback of the Sparrowhawk call also did not affect the host’s responses. However, the observed pattern suggests a possible influence of incubation advancement on host responses. Defensive behaviour peaked during the egg-laying and early incubation phases, with over 90% of eggs rejected, and fell slightly during advanced egg incubation. These findings suggest that Shrikes do not rely on auditory cues to detect parasitic threats. This study highlights the critical role of the breeding stage in shaping anti-parasitic strategies, and suggests that a strong ability to recognise parasitic eggs may reduce dependence on additional sensory cues. Further research is needed to examine the interplay between auditory and visual stimuli across different host species and geographic regions.

Summary National and continental-scale bird monitoring schemes, such as the Pan-European Common Bird Monitoring Scheme (PECBMS), are essential for tracking bird population trends across broad spatial scales. However, while these frameworks provide invaluable data for population monitoring, they may be less accurate in estimating species densities at small spatial scales, particularly for habitat-specialist species like the Red-backed Shrike Lanius collurio. This species is listed in Annex I of the EU Birds Directive, and its effective monitoring is a legal conservation obligation for EU Member States under the Natura 2000 framework. Ensuring accurate data on its population status is therefore critical for meeting international biodiversity targets. To evaluate this limitation, we compared density estimates from the Common Breeding Birds Survey (MPPL) with those obtained from intensive, targeted surveys across 53 study plots, each covering an area of 1 km², in eastern Poland. Although density estimates from MPPL and the targeted field study were correlated, a deeper analysis revealed that MPPL (2.1 individuals/km²) consistently underestimated densities recorded during targeted surveys (3.9 breeding pairs/km²). Using Generalised Linear Models (GLMs), we explored the habitat characteristics that may contribute to these discrepancies. Only two predictors, i.e. the proportion of buffer zones around arable fields and around mixed crops, were significantly associated with underestimation. In both cases, a higher share of buffer zones led to a greater difference between MPPL and targeted estimates, indicating that landscape structure influences detectability. Differences in survey timing between the two approaches, with MPPL visits conducted earlier in the breeding season, coupled with species-specific breeding behaviours (including peak activity later in the breeding season) may have influenced these differences. This study highlights that although bird surveys are an indispensable tool for analysing trends and comparing densities between surfaces over large spatial domains, their usefulness for studies at small spatial scales may be limited.

Agri-Environment Measures (AEM) are the primary policy tools under the European Union’s Common Agricultural Policy to combat farmland biodiversity loss, yet their effectiveness is highly variable. This synthesis paper summarizes findings of a doctoral thesis investigating drivers of variation in modelled biodiversity responses to AEM: (1) the use of different land-use intensity (LUI) metrics, (2) the types of AEM and their species-specific scale of effect, (3) landscape structural complexity across different regions. First, virtual species (i.e. species with known species-environment relationships) were used to explore how using alternative LUI metrics in biodiversity models influences the estimated species-AEM relationships. Second, bird observations for the Mulde River Basin in Germany were used to model farmland bird responses to different AEM across scales. These relationships varied across species and AEM type, but were generally strongest at the landscape level as compared to locally. Lastly, landscape-moderated effects of AEM on red-backed shrike (Lanius collurio) occurrences were analyzed across three study regions in Germany, Spain and Czechia. Positive shrike-AEM associations were stronger in structurally simple compared to complex landscapes, but this effect was inconsistent across regions. These findings exemplify species-, scale- and landscape-dependent AEM effects, and support AEM’s spatial targeting and regional tailoring.

In this work, we review past records of the Red-backed Shrike Lanius collurio in Algeria. Furthermore, we report a new observation of the species made in November 2023 of a juvenile individual spotted in Tawandert in the extreme south of Algeria. The identification was based on the observed plumage characteristics, including a greyish-brown crown and nape, pale rufous back, and faint barring above and below, with the white primary patch already visible. This record, following one in Djanet in 1960 and another in Bou Hanifia in 1977, represents the third for this species in Algeria and the first sighting in over 50 years, as well as the first documented occurrence in the southern Sahara region of the country of a species that normally follows an easterly route during post-breeding migration.

The vocal mimicry exhibited by female Common Cuckoos (Cuculus canorus), specifically their imitation of raptor calls, has been proposed as a strategy to reduce aggression from host species. Although this hypothesis has been challenged by studies using visual models of cuckoos and hawks, playback-only experiments support the idea of vocal mimicry, i.e. that cuckoo (brood parasite) calls may acoustically mimic those of predators. In this study, we tested the responses of the Red-backed Shrike (Lanius collurio), a known host species, to three types of acoustic stimuli: the female cuckoo’s “bubbling call” (which mimics a predator), the call of the Eurasian Sparrowhawk (Accipiter nisus), and a control call from the Eurasian Collared Dove (Streptopelia decaocto). Playback experiments were conducted both on the breeding grounds in Poland and during migration in Cyprus. Our results revealed that while both cuckoo and sparrowhawk calls elicited behavioural responses, these reactions were clearly distinct. Shrikes responded to sparrowhawk calls by hiding, indicative of predator avoidance, whereas cuckoo calls triggered alertness or approach behaviours. Notably, no response to cuckoo calls was observed during migration, outside the breeding context. This seasonal variation, along with the limited defensive response to cuckoo calls, indicates that vocal mimicry in this context may not serve a protective function. Instead, our findings highlight the shrikes’ nuanced ability to discriminate between acoustic stimuli and respond adaptively based on ecological context. These findings challenge the broad applicability of the predator mimicry hypothesis in cuckoos and emphasise the need for further comparative studies involving diverse host species and multimodal (audiovisual) stimuli.

Abstract Brood parasitism imposes strong selective pressures on host species, driving the evolution of eggshell coloration and egg discrimination mechanisms. We investigated changes in the egg appearance of Lanius collurio (Red-backed Shrike) over 130 years to understand their role in declining parasitism rates by Cuculus canorus (Common Cuckoo). We hypothesized that a decrease in intra-clutch variability accompanied by an increase in inter-clutch variability enhanced the shrike’s ability to distinguish parasitic eggs. We used calibrated digital photography to quantify eggshell coloration in both contemporary eggs and eggs from museum collections. Then, using visual modeling, we assessed intra- and inter-clutch variability by means of chromatic and achromatic contrasts as well as spotting pattern differences. The results revealed a significant increase in the divergence between inter- and intra-clutch chromatic contrast over time. A similar pattern was observed for pattern spectra differences. In the case of achromatic contrast, however, the opposite trend was noted. These findings suggest that long-term changes in the variability of eggshell coloration and patterning may have improved host defenses by increasing the detection and rejection of cuckoo eggs, potentially contributing to the decline in parasitism rates in L. collurio nests.

Migratory songbirds have an internal circannual genetic programme that controls the timing and extent of migratory flight activity, as demonstrated by experiments with birds held in cages. We used multisensor data loggers to record the timing and duration of all migratory flights during the annual cycle of 15 free-living individuals of red-backed shrikes Lanius collurio. Annual actograms unexpectedly revealed that the nocturnal migratory flights of the shrikes were organized in a highly structured way, with flights aggregated into segments that could be readily identified for all individuals, showing low variability and thus high consistency between individuals. These results suggest that the execution of migratory flights is under a high degree of control according to a rather detailed internal travelling plan for the annual migration cycle. Potentially, the control of migratory flight under natural conditions depends on a complex feedback process where external cues associated with the geographic, temporal and nutritional situation of the bird are required for the internal programme to properly regulate the successive segmental flight steps of the migratory journey. This would mean that the internal/genetic programme for control of bird migration is much more dynamic and complex than hereto assumed.

Blood parameters are widely used to evaluate the condition of birds. Typically, only a few parameters are used, such as the haemoglobin concentration, haematocrit, or the erythrocyte and leukocyte counts. The aim of this study was to present reference values of the haematological parameters of a free-living population of red-backed shrike (Lanius collurio) nestlings in east-central Poland. We assessed various blood parameters (haemoglobin concentration, erythrocyte and leukocyte, on blood smears for the erythrogram, leukogram and thrombocyte count), and examined their relationships with the brood size, biometrics conditions and hatching date. To reduce dimensionality and address the potential collinearity among variables, we conducted a Principal Component Analysis (PCA) and used the resulting components in Generalised Linear Mixed Models. None of the models yielded statistically significant effects. These results suggest a relatively stable physiological status among these nestlings, likely supported by a food-rich agricultural landscape. The haematological profiles presented here offer valuable baseline data for assessing the health of red-backed shrike populations and may support future comparative studies in wild birds.

Pigments present in avian eggshells are thought to serve many different adaptive functions. According to the sexually selected eggshell coloration hypothesis, the quantity of pigments in eggshells can serve as a signal of a female’s condition or of her maternal investment into eggs that elicits a higher investment from her partner. Here, we employed a comprehensive approach to test the sexually selected eggshell coloration hypothesis using a cup-nesting passerine with protoporphyrin-pigmented eggshells, the red-backed shrike Lanius collurio, as our model species. We used calibrated digital photography and visual modelling to assess eggshells appearance from an avian point of view. We estimated the condition of chicks and adult females using the Scaled Mass Index and additionally measured average width of growth bars on rectrices of adult females. We quantified the investment of males in terms of provisioning rates to offspring. We found that females in worse condition laid eggs with redder spots and the redness of spots was positively related to the condition of chicks. Visual modelling revealed that males were likely to perceive the variation in colour and brightness among clutches in the studied population, however, the provisioning rates of males were not related to any aspect of eggshell appearance. Thus, while eggshell coloration can act as a cue of female condition, we found no support for the signalling function of eggshell coloration in post-mating sexual selection in the red-backed shrike.

Preliminary data on the avifaunal diversity of the Corcova area (Mehedinți County) are presented in this study. Corcova commune, located in a hilly area, on the right bank of Motru River, in the eastern part of the Coșuștei Piedmont, is known as an important wine-growing center; the vineyards of Corcova were recognized in documents since the 15th century. The diversity of natural habitats (deciduous forests, meadows, pastures, hayfields, grassy lands, river courses, wetlands, ponds, riparian zones), which are interwoven with anthropogenic habitats (cultivated fields, access roads, rural perimeters, etc.) existing in the investigated area, represent suitable feeding, roosting and breeding sites for numerous bird species. The preliminary list includes 86 bird species observed in July-October 2023 and 2024. Of the birds highlighted, the species of European conservation concern listed in the Annexes of international legislation (Birds Directive EC /2009, Annex 1) caught our attention: Ciconia ciconia, Egretta garzetta, Pernis apivorus, Falco vespertinus, Alcedo atthis, Coracias garrulus, Picus canus, Dendrocoptes medius (Leiopicus medius), Dendrocopos syriacus, Lanius collurio, Ficedula albicollis, F. parva, Anthus campestris; and in need of conservation measures in order to mitigate the anthropogenic pressures and threats to which they are exposed (agricultural and forestry practices, extension of built-up areas, land use changes, fishing, etc.) and climatic pressures.

Summary Agricultural intensification has profoundly transformed Europe’s landscapes, driving widespread declines in farmland bird populations. Among the most pressing threats is the loss of meadows, either through conversion to arable land as a result of intensification, or through agropastoral abandonment leading to shrub encroachment. Although farmland bird populations in Central and Eastern Europe have historically declined more slowly than in other regions, recent evidence shows that even once-common species are now in decline. This highlights the urgent need to quantify these trends and identify their underlying drivers. In this study, we investigate habitat preferences and factors underlying the severe, over 30-year decline of Red-backed Shrike Lanius collurio , an iconic farmland species and key bioindicator of grassland biodiversity. Our research focused on a 440-ha alluvial floodplain in Slovenia’s Sub-Pannonian region, a site considered a national stronghold for the species. Territory surveys were conducted intermittently from 1992 to 2025, with detailed habitat mapping available from 2004 to 2022. Consistent with previous studies, our results indicated that breeding Red-backed Shrikes primarily occupied ecotonal habitats marked by extensive meadow cover, moderate shrub density, and high habitat heterogeneity. Alarmingly, between 1992 and 2025, the population declined by 92.44%, decreasing from 172 territories to just 13. The steep decline observed was likely driven by agricultural intensification, persisting under the Common Agricultural Policy (CAP), with conversion of meadows into arable land and the loss of traditional management leading to shrub encroachment. The latter emerged as the strongest predictor of population decline in the most recent years. Our findings emphasise the urgent need to protect, manage, and restore meadows to prevent further biodiversity loss. Considering the relatively better historical status of farmland bird populations in Central and Eastern Europe compared with their Western European counterparts, this worrying trend indicates that similar declines are likely widespread, highlighting the need for immediate research and targeted conservation efforts.

Predator recognition is essential for prey survival, allowing for appropriate antipredator strategies. Some bird species, such as the red-backed shrike (Lanius collurio), distinguish not only between predators and non-threatening species but also between different predator species. Earlier studies have identified general predator “key features”, especially beak shape and talons, as critical for predator recognition. The question, though, still remains of whether exchanging predator key features with those of nonpredatory species or, alternatively, completely removing them, have different or equal impact on recognition. Here we tested to ascertain whether the presence of the “incorrect key features” of a harmless pigeon (Columba livia) placed on a common kestrel (Falco tinnunculus) body impairs predator recognition more efficiently than the absence of any key features. We presented an unmodified kestrel dummy and two modified kestrel dummies (one with pigeon key features, the other lacking key features) to wild red-backed shrikes defending their nest. The shrikes attacked the unmodified dummy kestrel more intensively than both kestrel modifications when defending the nest. However, shrikes did not show different responses to the kestrel with pigeon key features and the featureless kestrel. Our findings show that the absence and exchange of key features have the same effect in this case. These results are discussed in the context of recognition of a specific predator species and predators as a category in general.

The recent colonization of new breeding territories in Central Spain by the Red-backed Shrike (Lanius collurio) at the end of the 20th century is of significant biogeographical and ecological interest.This geographical expansion is paradoxical given the declining trend of the species across much of its global range.This paper presents findings on the biogeographical patterns and distribution range of the Red-backed Shrike in the Iberian Central system, as well as its habitat preferences, altitudinal shifts, potential distribution, and estimated population during the breeding period in the Community of Madrid (Spain), based on field work conducted between 2018 and 2020.The breeding population in the study area is consistently composed of approximately 500 pairs, with a preference for cool, open areas such as pastures or mosaics of meadows with thorny shrubs, situated above 1,000 m above sea level.These characteristics differentiate this population from those in the Spanish Eurosiberian region.Additionally, the anthropic and socio-economic peculiarities of the study area should be considered when establishing appropriate conservation measures to prevent local extinction in our changing world.

data on migratory birds in their non-breeding grounds are scarce.After ringing and gathering biometric and moult data for more than twenty years in the countries of the southern part of Africa, we are now summarizing our findings.Here, our focus is on the plumage of first-year and adult Red-backed Shrikes Lanius collurio developing during their stay as an aide for the age distinction in the field.We present moult data of both age groups and show moult progression and plumage variation by photographic evidence.

Epidermoptidae (Acariformes: Astigmata) are permanent ectoparasites of birds; representatives of some genera have evolved phoretic associations with louse flies (Hippoboscidae). Moreover, mites of some genera hyperparasitise their phoretic carriers, using them for oviposition and in some cases for feeding. In the course of research focused on bird migrations and avian ectoparasites carried out in Eastern Slovakia in 2022 and 2023, we collected 76 hippoboscid flies of 7 species from 71 birds of 20 species; of these flies, 6 individuals (8 %) were parasitised by epidermoptid mites. Promyialges italicus Faradonbeh et al., 2019 was found on the wings of Ornithomya avicularia (Linnaeus, 1758) and O. biloba Dufour, 1827, both from barn swallow, Hirundo rustica Linnaeus, 1758. Myialges anchora Sergent and Trouessart, 1907 was found on the abdomens of louse flies of three species: Ornithoica turdi (Olivier in Latreille, 1811), Ornithomya fringillina Curtis, 1836, and O. avicularia (Linnaeus, 1758) from the three different avian hosts: Lanius collurio Linnaeus, 1758, Acrocephalus arundinaceus (Linnaeus, 1758), and Turdus merula Linnaeus, 1758, respectively. Promyialges italicus has been recorded on a host other than Pseudolynchia canariensis (Macquart in Webb and Berthelot, 1839) for the first time. Neither species of this mite has been reported in Slovakia.

West Nile fever is a very dangerous zoonotic viral disease of animals and humans. It is a naturally occurring focal disease, the natural cycle of which involves a natural reservoir of pathogens, such as wild birds, and vectors, such as mosquitoes, ticks, etc. Today, the problem of West Nile fever is becoming increasingly relevant from an epidemiological point of view. Natural foci of this disease pathogen have been present in Ukraine for a long time in the southern and eastern regions, but now, due to climate change, there are changes in the ecology of both natural carriers and vectors, which significantly changes the epidemiological risks to humans. Over the past few years, in particular, in 2024, an increase in human cases, including fatalities, has been recorded in Ukraine. At the same time, there is a lack of up-to-date information on the circulation of West Nile virus and other flaviviruses (Usutu virus, etc.) in the natural reservoir and among vectors in Ukraine. Our research aimed to conduct serological monitoring in Ukraine among wild forest birds, which are one of the main natural reservoirs of the West Nile virus. During 2023-2024, 268 blood samples and 9 egg yolks of wild Passeriformes (families buntings, finches, true sparrows, tits, bushtits, shrikes, wagtails, Hirundinidae) and Piciformes were collected in Kharkiv, Kyiv, Poltava, Odesa, and Khmelnytsky regions. Blood serum and egg yolks were tested in the ELISA ID.Vet - ID Screen West Nile. It was found that antibodies to WN virus were present in blood samples from Great Tits (seroprevalence from 20% to 100% depending on the region), Song Thrush (60–100%), Blackbird (93%-100%), Chaffinch (100%), Goldfinch (100%), House Sparrow (100%), Greenfinch (10% and 100%), hawfinch (100%), Jays (50%), Field Sparrow (20% and 25%), and Great Reed warbler (40%), reed warbler (33.3%), Сommon whitethroat (25%), Robin (100%), Yellowhammer (100%), Blackcap (100%), Spotted flycatcher (100%), Pied flycatcher (100%), Thrush nightingale(100%). No antibodies to the WN virus were detected in the barn Swallow, Sedge Warbler, Paddyfield Warbler, Collared Flycatcher, Reed Bunting, Spanish Sparrow, Common Woodpecker, Goldfinch, Red-backed Shrike. Seropositivity was found in wild birds from all regions studied. The highest percentage of seropositive birds was found in Poltava (86%, 58%) and Khmelnytsky (67%) regions, and the lowest in Kyiv (9%) and Odesa (17.1%) regions. We also found a difference in seropositivity in different years. Thus, in 2023 it was 27.4%, and in 2024 it was 50.5%

Farmland, a vital terrestrial environment, has seen significant changes due to intensified agricultural practices and plastic pollution. Assessing plastic pollution in farmed areas remains challenging, and understanding its impacts on agricultural ecosystems is limited. The aim of the was to determine whether plastic pollution in agricultural landscapes depends on the type of crops. We used the Red-backed Shrike (Lanius collurio), an indicator bird species and investigated plastic contamination of 122 of its nests. We found plastic waste in 82.1 % of nests, totalling 6234 items weighing 197.2 g. On average, each nest contained 55.7 waste items, constituting approximately 4.3 % of the nest's mass. Plastic string fibres were predominant, making up 95.6 % of the items and 90.7 % of the mass. This variation may be due to different straw and hay management practices and varying levels of vigilance in removing plastic remnants. Contamination levels varied significantly among farmland types, with cultivated fields showing the highest contamination and meadows the lowest.

Every year, several hundred million birds cross the Mediterranean on their migration from Eurasia to their wintering quarters in Africa. As many migrants travel at night or at high altitudes, direct observations of bird migration are difficult and thus our information about migrating species, numbers and timing is incomplete. An indirect way to assess autumn migration is the analysis of prey remains of Eleonora’s Falcons (Falco eleonorae). These falcons breed in large colonies on islands in the Mediterranean and on the Canary Islands. Many migrants have to pass these islands on their flight to their African wintering quarters. Eleonora’s Falcons appear to be adapted to the autumn bird migration and raise their young between August and October, when migrating birds are abundant. When nestlings have to be fed, falcons exclusively hunt small birds of 10 to 150 g body mass, whereas they prey mostly on aerial invertebrates (Coleoptera, Hymenoptera, Diptera, Orthoptera, Hemiptera, Odonata, Lepidoptera) from November to July. We studied Eleonora’s Falcons from 1965 to 2001 on a rocky islet, north of Crete, which harboured a colony of about 200 breeding pairs. In 1969, 1971, 1977, and 1988 we systematically monitored and collected the pluckings and cached food items in 22 to 36 nest sites each year. Pluckings were systematically analysed later in Germany using a reference collection of bird feathers for identification. In total, we determined more than 111 prey species (mostly Passerines) comprising more than 13,450 individuals. The top 12 prey species were: Willow Warbler (27.8% of all prey items), Red-backed Shrike (10.7%), Spotted Flycatcher (9.9%), Whinchat (8.8%), Common Whitethroat (5.1%), Wood Warbler (3.8), Tree Pipit (2.9%), Icterine Warbler (2.5%), Greater Short-toed Lark (2.5%), Northern Wheatear (1.8%), Common Nightingale (1.6%), and European Pied Flycatcher (1.5%). Eleonora’s Falcons are selective hunters to some degree; thus, the phenology and abundance data derived from the plucking analyses are biased towards slow-flying species or smaller birds (only up to a body mass of 150 g). When the young falcons develop and grow, food demand increases concomitantly. Comparing the total weight of prey over time indicates a correlation with food demand and in consequence with the number of prey items brought to the nest sites by the falcons.