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Aggression towards brood parasites is an important component of host frontline defences. Hosts sometimes adjust this behaviour based on their previous experience with the parasites. Here, we explore whether host aggression towards the parasite dummy is affected by (1) the number of parasite visits prior to the dummy experiment and (2) the time elapsed since the last parasite visit (both identified from continuous video-recordings of host nests). As a model species, we used the great reed warbler (Acrocephalus arundinaceus), which is a major host of the common cuckoo (Cuculus canorus). At our study site, this host shows high aggression towards the cuckoo and experiences high parasitism rates. We found that the hosts increased their aggression towards the parasite dummy with increasing number of previous parasite visits. Moreover, the hosts retained aggression at high levels if the last parasite visit occurred recently. However, these behavioural patterns were or tended to be significant only in host males. Our findings underscore the importance of individual experience in shaping host aggression towards brood parasites, at least in the more aggressive sex. Therefore, we recommend considering the information on prior host‒parasite interactions when planning dummy experiments, because it may contribute to a deeper understanding of the variability in host defences against brood parasitism. Significance statement: This study reveals that the great reed warbler, one of the major common cuckoo hosts, adjusts its anti-cuckoo aggression based on the number of prior cuckoo visits. Male great reed warblers, in particular, become more aggressive with repeated cuckoo visits and when the visit occurred recently. These findings emphasize the role of individual experience in shaping defensive behaviours against brood parasitism and offer deeper insights into the variability of host defences. Understanding how the previous exposures to the parasite influence host aggression can refine experimental approaches and improve our knowledge of host-parasite interactions. [ABSTRACT FROM AUTHOR]

Aim: Ongoing climate changes represent a major determinant of demographic processes in many organisms worldwide. Birds, and especially long‐distance migrants, are particularly sensitive to such changes. To better understand these impacts on long‐distance migrants' breeding productivity, we tested three hypotheses focused on (i) the shape of the relationships with different climate variables, including previously rarely tested quadratic responses, and on regional differences in these relationships predicted by (ii) mean climatic conditions and (iii) by the rate of climate change in respective regions ranging from Spain to Finland. Location: Europe. Time Period: 2004–2021. Major Taxa Studied: Long‐distance migratory passerine birds. Methods: We calculated breeding productivity from constant effort ringing sites from 11 European countries covering 34° of latitude, and extracted temperature‐ and precipitation‐related climate variables from E‐OBS and NASA MODIS datasets. To test our hypotheses, we fitted GLMM and Bayesian meta‐analytic models. Results: We revealed hump‐shaped responses of productivity to temperature, growing degree‐days, green‐up onset date, and precipitation anomaly, and negative responses to intense and prolonged rains across the regions. The effects of March temperature and April growing degree‐days were more negative in cold than in warm regions, except for the region with the highest accumulated heat, whereas increasing June precipitation anomalies were associated with higher productivity in both dry and wet regions. Productivity responses to climate were unrelated to the rate of climate warming. Main Conclusions: The influence of climate on bird productivity proved to be frequently nonlinear, as expected by ecological theory. The rate of climate change is less important than regional interannual variability in climate (which is predicted to increase), but this may change with the progression of climate change in the future. Productivity declines in long‐distance migratory songbirds are particularly expected if out‐of‐norm water excess increases in frequency or strength. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Breeding simultaneously with other members of a population can be induced socially or by the seasonality of climatic conditions or availability of resources. Simultaneous breeding has several fitness benefits, including mate choice, food acquisition or protection against nest predators or brood parasites. In this study, we investigate how spring temperatures at a breeding site affect breeding synchrony and brood parasitism in a great reed warbler (Acrocephalus arundinaceus) population heavily parasitised by the common cuckoo (Cuculus canorus). We predict that in colder springs, the hosts will start breeding later and, thus, their nest attempts will be more synchronised, resulting in a lower proportion of parasitised nests than in warmer springs. Our results confirmed that the hosts started to breed significantly later in colder springs and were more synchronised than in warmer springs. Nevertheless, we found no significant effect of host breeding synchrony on the proportion of parasitised nests. This finding challenges the widely accepted scenario that synchronised breeding leads to a lower proportion of parasitised nests in a host population. It is possible that in strongly parasitised host populations, the high parasite density makes the host breeding synchrony less effective in mitigating the negative impact of brood parasitism. Further research is needed to explore the potential influence of parasite density on the effectiveness of host breeding synchrony as an antiparasitic defence. [ABSTRACT FROM AUTHOR]

The European Union is the world's largest producer of sugar beet and one of the main consumer markets in the world. The EU market is very specific as for 50 years, it was one of the most regulated markets in the agri-food sector. For more than three decades, the Union maintained an extremely costly supply management regime in its domestic sugar market through heavy price support and import duties. This system resulted in domestic prices being three times higher than the world market prices and a surplus of production, which could only be exported thanks to substantial subsidies. The aim of this article is to identify the trends and determinants of the EU sugar market to predict its future development as accurately as possible. The research method used is a two-equation econometric model determining the supply of sugar and its price on the European Union market. The results of the econometric model show that sugar supply in the EU market is determined by the volume of sugar production, initial sugar stocks, import of raw sugar, and sugar beet yield per hectare. Furthermore, the model implies that the price of sugar is determined by the sugar price in the previous period and by political changes. The econometric model served as a basis for the calculation of predicted volume of sugar supply and sugar prices inside the European Union. The prediction implies that between 2023 and 2032, sugar supply will decline by 4.5%. At the same time, the price of sugar on the EU market will increase by 11.5% in the period considered. [ABSTRACT FROM AUTHOR]

Geographic distribution models of environmentally stable isotopes (the so‐called "isoscapes") are widely employed in animal ecology, and wildlife forensics and conservation. However, the application of isoscapes is limited to elements and regions for which the spatial patterns have been estimated. Here, we focused on the ubiquitous yet less commonly used stable sulfur isotopes (δ34S). To predict the European δ34S isoscape, we used 242 feather samples from Eurasian Reed Warbler (Acrocephalus scirpaceus) formed at 69 European wetland sites. We quantified the relationships between sample δ34S and environmental covariates using a random forest regression model and applied the model to predict the geographic distribution of δ34S. We also quantified within‐site variation in δ34S and complementarity with other isotopes on both individual and isoscape levels. The predicted feather δ34S isoscape shows only slight differences between the central and southern parts of Europe while the coastal regions were most enriched in 34S. The most important covariates of δ34S were distance to coastline, surface elevation, and atmospheric concentrations of SO2 gases. The absence of a systematic spatial pattern impedes the application of the δ34S isoscape, but high complementarity with other isoscapes advocates the combination of multiple isoscapes to increase the precision of animal tracing. Feather δ34S compositions showed considerable within‐site variation with highest values in inland parts of Europe, likely attributed to wetland anaerobic conditions and redox sensitivity of sulfur. The complex European geography and topography as well as using δ34S samples from wetlands may contribute to the absence of a systematic spatial gradient of δ34S values in Europe. We thus encourage future studies to focus on the geographic distribution of δ34S using tissues from diverse taxa collected in various habitats over large land masses in the world (i.e., Africa, South America, or East Asia). [ABSTRACT FROM AUTHOR]

Stable isotope analysis provides valuable insights into the ecology of long-distance migratory birds during periods spent away from a specific study site. In a previous study, Swedish great reed warblers (Acrocephalus arundinaceus) infected with haemosporidian parasites differed in feather isotope ratios compared to non-infected birds, suggesting that infected and non-infected birds spent the non-breeding season in different locations or habitats. Here, we use a novel dataset comprising geolocator data, isotopes, and haemosporidian infection status of 92 individuals from four Eurasian populations to investigate whether parasite transmission varies with geography or habitats. We found that the probability of harbouring Plasmodium and Leucocytozoon parasites was higher in birds moulting in the eastern region of the non-breeding grounds. However, no geographic pattern occurred for Haemoproteus infections or overall infection status. In contrast to the previous study, we did not find any relationship between feather isotope ratios and overall haemosporidian infection for the entire current dataset. Plasmodium-infected birds had lower feather δ15N values indicating that they occupied more mesic habitats. Leucocytozoon-infected birds had higher feather δ34S values suggesting more coastal sites or wetlands with anoxic sulphate reduction. As the composition and prevalence of haemosporidian parasites differed between the old and the current dataset, we suggest that the differences might be a consequence of temporal dynamics of haemosporidian parasites. Our results emphasize the importance of replicating studies conducted on a single population over a restricted time period, as the patterns can become more complex for data from wider geographical areas and different time periods. [ABSTRACT FROM AUTHOR]

Background: Pandemics as health and humanitarian crises have exerted traceable impacts on food security. Almost all past and current pandemics have created a food crisis that affects a share of the global population and threaten global food security. With the more frequent outbreaks of emerging and re-emerging diseases or pandemics, this paper looks at the various types of impacts from the current coronavirus crisis and past pandemics to identify their major impact on food security. Scope: To this effect, key strategies that could be put in place to ensure the efficient resilience of food systems before, during, and after the pandemics to mitigate the negative impact of the pandemics on global food security are recommended. The most recent effects of the current coronavirus crisis have been disruptions in the flow of farm labourers and inefficient farm operations leading to postharvest food losses. Key findings and conclusions: Modification of diets between social groups has also been observed. Future response orientations to prevent and mitigate the effects of pandemics on food security will consider pro-active and adapted policy, program, and institutional actions towards the systemic development of global food systems as an interconnected network. Highlights: • Before the 20thcentury hunger and illnesses might be traced to climatic changes. • The catastrophes in human history elicit various reactions – defence, reflection. • In the 19thcentury, lower quality of food further exacerbated the effects of famines. • Skills required for effectivemanagement of the flow of goods and services are in high demand. • Alternative food resources exist during pandemic and food shortage. • Strategizing to ensure food access and self-sufficiency during a pandemic is possible. [ABSTRACT FROM AUTHOR]

This research investigates the proactive and reactive measures applied by Czech and Hungarian auto- motive companies following Russia’s invasion of Ukraine. We apply a qualitative methodology and analyse interviews with company managers to learn about the applied measures. The results reveal that the resilience gained during the COVID-19 pandemic involved proactive measures, which companies have kept in place. Reactive measures involved production replanning and alternative transportation. Adopting multiple sourcing strategies in the automotive sector is limited and more reactive rather than proactive. The important antecedents of agility are information sharing and cooperation within multinationals. [ABSTRACT FROM AUTHOR]

Climatic conditions affect animals but range‐wide impacts at the population level remain largely unknown, especially in migratory species. However, studying climate–population relationships is still challenging in small migrants due to a lack of efficient and cost‐effective geographic tracking method.Spatial distribution patterns of environmental stable isotopes (so called 'isoscapes') generally overcome these limitations but none of the currently available isoscapes provide a substantial longitudinal gradient in species‐rich sub‐Saharan Africa. In this region, sulphur (δ34S) has not been sufficiently explored on a larger scale.We developed a δ34S isoscape to trace animal origins in sub‐Saharan Africa by coupling known‐origin samples from tracked migratory birds with continental remotely sensed environmental data building on environment–δ34S relationships using a flexible machine learning technique. Furthermore, we link population‐specific nonbreeding grounds with interannual climatic variation that might translate to breeding population trends.The predicted δ34S isotopic map featured east–west and coast‐to‐inland isotopic gradients and was applied to predict nonbreeding grounds of three breeding populations of Eurasian Reed Warblers Acrocephalus scirpaceus with two distinct migratory phenotypes. Breeding populations as well as migratory phenotypes exhibited large‐scale segregation within the African nonbreeding range. These regions also differed substantially in the interannual climatic variation, with higher interannual variability in the eastern part of the range during 2001–2012. Over the same period, the eastern European breeding population seemed to have experienced a more steep decline in population size.The link between migratory patterns and large‐scale climatic variability appears important to better understand population trajectories in many declining migratory animals. We believe animal tracing using sulphur isotopes will facilitate these efforts and offers manifold ecological and forensic applications in the biodiversity hotspot of sub‐Saharan Africa. [ABSTRACT FROM AUTHOR]

Wild mushroom foraging has a long tradition, especially in the region of Central Europe. Wild mushrooms are a valuable food resource, as they provide nutritional benefits to the European population. They offer a relatively high content of protein and are traditionally used in many European cuisines as a substitute for meat. This is particularly true in times of crisis, such as wars and pandemics. The study presented in this paper shows that wild mushrooms can substitute around 0.2 percent of daily protein intake and contribute around 3% to the agricultural output of the Czech economy, which was selected as a representative for Central Europe. The calculated real price of wild mushrooms indicates their increasing popularity as a source of food protein in Central Europe, while their price seems to be independent of the quantity supplied. [ABSTRACT FROM AUTHOR]

Wild mushroom foraging has a long tradition in Central European countries. Protein from wild mushrooms is an important part of Central European diets and has served historically as a meat protein substitute. In view of climate change, this protein source may become scarce. This study investigated the effects of temperature and precipitation on wild mushrooms using the Dickey–Fuller test and ordinary least squares method. The results from the Czech Republic show that when the precipitation change was increased by one unit, the change in the amount of foraged mushrooms went up by twenty-seven tons, while the factor of temperature was found to be statistically insignificant. This indicates that with a decline in precipitation, possibly due to climate change, there will be a decline in the amount of wild mushrooms foraged. [ABSTRACT FROM AUTHOR]

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

In some populations of the host of brood parasites, more than two parasite eggs may be laid in a single nest. This phenomenon is known as multiple parasitism, representing a cost to both the host and parasite. In this study, we analysed a long-term dataset (2007–2021) focusing on multiple parasitism of the common cuckoo (Cuculus canorus) parasitizing the great reed warbler (Acrocephalus arundinaceus). The annual parasitism rate was on average 54.3% and varied between 5.8% and 92.2%, depending on the year. Out of 720 parasitized nests, double parasitism was recorded in 172 (23.9%) nests, triple in 51 (7.1%) nests, quadruple in 10 (1.3%) nests, and, exceptionally, in the years of heavy parasitism (about 90%), quintuple parasitism was recorded in three (0.4%) nests. The rate of multiple parasitism ranged from 0 to 63% inter-annually and strongly correlated with the parasitism rate and the total number of parasite eggs found. Furthermore, the number of cuckoo eggs laid per one nest increased with the decreasing daily availability of host nests that were at a suitable breeding stage for parasitism. Both genetic and egg phenotype analyses revealed that no cuckoo female laid more than one egg in the same host nest. Using data on long-term parasite–host interactions and from continuous video recording, as well as progressive methods to assign parasite offspring thus helped us better understand various aspects of multiple parasitism in hosts heavily parasitized by an evictor brood parasite. Significance statement: Laying more parasite eggs in one host nest (i.e. multiple parasitism) is common in brood parasites whose nestlings share the nest with nestmates. In the species where the parasite's nestling kills its nest mates, multiple parasitism should be rare because it is costly for the parasite. However, in host populations with high parasitism rates, multiple parasitism occurs more often than predicted. Using long-term and video-recording data, we quantified multiple parasitism in the common cuckoo across years and host egg-laying sequences. We found that the rate of multiple parasitism is positively related to the parasitism rate and that the lower the number of nests suitable for parasitism, the higher the number of parasite eggs in one nest. Based on genetic and egg phenotype analyses, we also showed that individual parasitic females avoid laying in the nests they had already parasitized. [ABSTRACT FROM AUTHOR]

This paper deals with the design and operational evaluation of a timber tractor-trailer unit with a hybrid trailer drive. The source of electrical energy for the two induction motors driving the front wheels of the tandem trailer axle is a battery, which is recharged by an induction machine operating as a generator during periods of a lower demand for power from the tractor diesel engine. An electric drive was designed for the defined working cycle of the tractor-trailer unit, and its loading characteristics were tested in the laboratory. The parameters measured on the field tests during timber forwarding were battery voltage and power, and the energy balance. Three adjustment levels of the potentiometer controlling the trailer hybrid drive (50, 75 and 100%) were tested at three different forwarding distances of 100, 500 and 1000 m. Additionally, any slippage of the prime mover wheels and trailer was measured. The maximum peak power taken from the battery was ca. 33 kW during the field tests, whilst the drive was able to deliver a peak output of up to 72 kW for 10 s and permanently up to ca. 50 kW. Even in harsh terrain conditions, the electric drive assisted the combustion engine only when the loaded tractor-trailer unit was travelling uphill. The hybrid drive operation was sustainable for the whole working shift, without the need for recharging when the potentiometer was set to 50%. This appropriate setting of the potentiometer controlling the trailer's hybrid drive reduced the slipping of the driven wheels of the tractor-trailer unit whilst travelling uphill. [ABSTRACT FROM AUTHOR]

Individual identification is crucial for studying animal ecology and evolution. In birds this is often achieved by capturing and tagging. However, these methods are insufficient for identifying individuals/species that are secretive or difficult to catch. Here, we employ an automatic analytical approach to predict the identity of bird females based on the appearance of their eggs, using the common cuckoo (Cuculus canorus) as a model species. We analysed 192 cuckoo eggs using digital photography and spectrometry. Cuckoo females were identified from genetic sampling of nestlings, allowing us to determine the accuracy of automatic (unsupervised and supervised) and human assignment. Finally, we used a novel analytical approach to identify eggs that were not genetically analysed. Our results show that individual cuckoo females lay eggs with a relatively constant appearance and that eggs laid by more genetically distant females differ more in colour. Unsupervised clustering had similar cluster accuracy to experienced human observers, but supervised methods were able to outperform humans. Our novel method reliably assigned a relatively high number of eggs without genetic data to their mothers. Therefore, this is a cost-effective and minimally invasive method for increasing sample sizes, which may facilitate research on brood parasites and other avian species. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tissue samples are frequently collected to study various aspects of avian biology, but in many cases these samples are not used in their entirety and are stored by the collector. The already collected samples provide a largely overlooked opportunity because they can be used by different researchers in different biological fields. Broad reuse of samples could result in multispecies or large‐scale studies, interdisciplinary collaborations, and the generation of new ideas, thereby increasing the quality and impact of research. Sample reuse could also reduce the number of new samples needed for a study, which is especially pertinent to endangered species where sample collection is necessarily limited. Importantly, reusing samples may be mutually beneficial for both the researchers providing samples and those reusing them. Here, we identify the benefits of sample reuse, describe currently available sources of already collected samples and their limitations, and highlight the wide range of potential applications in a single research field – avian isotopic ecology. To facilitate the reuse of avian samples worldwide and across research fields, we introduce the AviSample Network metadata repository. The main aims of this metadata repository are to collate and provide access to descriptions of available avian tissue samples. We contend that the creation of the AviSample Network metadata repository will provide the opportunity for new collaborations and studies. Moreover, we believe that this will help create research connections between ornithologists across the globe and encourage sample reuse in other fields. [ABSTRACT FROM AUTHOR]

How blood parasite infections influence the migration of hosts remains a lively debated issue as past studies found negative, positive, or no response to infections. This particularly applies to small birds, for which monitoring of detailed migration behavior over a whole annual cycle has been technically unachievable so far. Here, we investigate how bird migration is influenced by parasite infections. To this end, we tracked great reed warblers (Acrocephalus arundinaceus) with multisensor loggers, characterized general migration patterns as well as detailed flight bout durations, resting times and flight heights, and related these to the genus and intensity of their avian haemosporidian infections. We found migration distances to be shorter and the onset of autumn migration to be delayed with increasing intensity of blood parasite infection, in particular for birds with Plasmodium and mixed‐genus infections. Additionally, the durations of migratory flight bout were prolonged for infected compared to uninfected birds. But since severely infected birds and particularly birds with mixed‐genus infections had shorter resting times, initial delays seemed to be compensated for and the timing in other periods of the annual cycle was not compromised by infection. Overall, our multisensor logger approach revealed that avian blood parasites have mostly subtle effects on migratory performance and that effects can occur in specific periods of the year only. [ABSTRACT FROM AUTHOR]

Annual cycle events may be interlinked, influence following annual cycle stages, and may alter performance of individuals. Such links, called carry-over effects, can explain individual variation in timing or reproductive success in migratory species. Identifying the key links affecting fitness may reveal the mechanisms of species population dynamics but the current evidence for the strongest carry-over effects is equivocal. Here, we aim to assess the carry-over effects in great reed warblers Acrocephalus arundinaceus, a long-distance migratory songbird, using 103 full-annual tracks from three European and two Asian breeding populations. Our results showed strong positive relationships within autumn and spring migration periods and buffering capacity of the non-breeding period preventing events to carry over between these periods. Moreover, we found no profound relation between the non-breeding habitat quality or seasonality (quantified using stable isotopes and remote sensing data) and the timing of spring migration. The strongest carry-over effects occurred in individuals from the southern European breeding population compared to the northern and the central European populations. A moderate relationship between the habitat seasonality during moult and the spring migration timing indicates the importance of the complete moult. The overall weak carry-over effects of non-breeding habitat conditions found in this study contrast with previous results and imply between-species differences in these crucial relationships. Moreover, the population-specific carry-over effects highlight the importance of multi-population approach and advise caution in interpretation of results from single-population studies. Finally, the carry-over effect from the moulting period indicates the significance of a so-far neglected link in the species. Significance statement: Environmental conditions vary in space and time. Therefore, migratory species adjust the timing of migration in order to maximise their fitness. However, the links between annual cycle events in multiple populations and the consequences of environmental conditions outside the breeding range are scarcely known. In this study, we used tracking data of the great reed warbler, an insectivorous bird species breeding across western Eurasia and wintering in Africa, to study a complex system of links between annual events. We found that the strength of these links differed between geographically distinct populations but not between sexes. Moreover, harsh environmental conditions during moult delayed the timing of subsequent events. Our findings could help explain large-scale differences in population size changes observed in some species and highlight the importance of energetically demanding moult period for the life of migratory species. Finally, our results demonstrate the need for multi-population approach in studies on seasonal interactions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An animal's gut microbiota (GM) is shaped by a range of environmental factors affecting the bacterial sources invading the host. At the same time, animal hosts are equipped with intrinsic mechanisms enabling regulation of GM. However, there is limited knowledge on the relative importance of these forces. To assess the significance of host-intrinsic vs environmental factors, we studied GM in nestlings of an obligate brood parasite, the common cuckoo (Cuculus canorus), raised by two foster species, great reed warblers (Acrocephalus arundinaceus) and Eurasian reed warblers (A. scirpaceus), and compared these with GM of the fosterers' own nestlings. We show that fecal GM varied between cuckoo and warbler nestlings when accounting for the effect of foster/parent species, highlighting the importance of host-intrinsic regulatory mechanisms. In addition to feces, cuckoos also expel a deterrent secretion, which provides protection against olfactory predators. We observed an increased abundance of bacterial genera capable of producing repulsive volatile molecules in the deterrent secretion. Consequently, our results support the hypothesis that microbiota play a role in this antipredator mechanism. Interestingly, fosterer/parent identity affected only cuckoo deterrent secretion and warbler feces microbiota, but not that of cuckoo feces, suggesting a strong selection of bacterial strains in the GM by cuckoo nestlings. [ABSTRACT FROM AUTHOR]

Dozens of studies have documented that brood parasites are well adapted to a brood parasitic lifestyle but not all parasitism events are successful. Co‐evolution between brood parasites and their hosts is a dynamic process so it is reasonable to expect that a female brood parasite may commit errors during egg deposition by laying her eggs outside the laying period of the host, with consequent impacts on her fitness. Using an extensive dataset from a long‐term study, we evaluated egg‐laying patterns and errors related to the timing of egg‐laying in the Common Cuckoo Cuculus canorus (hereafter 'Cuckoo'). Specifically, we tested whether the Cuckoo avoids laying before or on the day of host clutch initiation to reduce the risk of rejection of parasitic eggs, whether laying errors will be more frequent in periods with a lack of active host nests, and whether the laying errors will be more frequent in periods with intense Cuckoo parasitism and a consequent lack of suitable host nests. We found that about one‐third of Cuckoo eggs were laid on the host clutch initiation day or 1 day before, and the percentage of Cuckoo eggs laid decreased thereafter. Surprisingly, the probability of Cuckoo egg acceptance by the hosts was not affected by the egg‐laying stage of the host clutch. Errors in the timing of egg‐laying with fatal consequences (i.e. those precluding Cuckoo hatching because of laying in incubated or deserted clutches) were recorded in about 5% of cases. Only laying date of a Cuckoo egg had a significant effect on the probability of errors, which increased during the breeding season. This may be related to the higher number of deserted and incubated host nests at the site at the end of the breeding season. Errors in egg‐laying may be attributed to young and inexperienced females but also impaired body condition or intraspecific competition may cause this behaviour. Future studies, which will test these possible explanations, will help to understand better the mechanism of co‐evolutionary arms races and differences between host specialist and generalist brood parasites in various host–parasite systems. [ABSTRACT FROM AUTHOR]

The co-evolutionary arms race between brood parasites and their hosts involves stepwise adaptive changes on the side of the parasites as well as hosts. In response to avian brood parasitism, host females may eject a parasitic egg, bury the parasitized clutch or desert it. After nest desertion, females commonly re-nest and may move further to avoid being parasitized again. Here we tested whether and under which conditions the within-season re-nesting prevents brood parasitism in the great reed warbler (Acrocephalus arundinaceus). We analysed 78 re-nesting events of 58 naturally parasitized host females that deserted their nests in response to the common cuckoo (Cuculus canorus) parasitism. The parasitism rate in the replacement nests of these females was 60%. Most of these females built their replacement nests less than 143 m from the previous nests. The probability for replacement nests to be parasitized increased with increasing instantaneous parasitism rate but not with the re-nesting distance or timing of the replacement clutch. We explain this by the high level of cuckoo parasitism across the whole study site during the major part of the breeding season. To better understand the patterns and consequences of host re-nesting behaviour, further studies in other host populations with different levels of cuckoo parasitism would be desirable. Significance statement: Although various factors affecting avian breeding dispersal have been studied, little is known about the relationship between the within-season re-nesting distances and fate of replacement nests. Moreover, there is a lack of studies focusing on the consequences of re-nesting dispersal in response to brood parasitism and, to our best knowledge, this is the first study investigating this topic in a host of an evictor parasite. [ABSTRACT FROM AUTHOR]

Several hypotheses have been proposed to explain the mechanisms responsible for maintenance of host-specific gentes in the common cuckoo (Cuculus canorus). Some of them expect that when adult cuckoos return to lay their eggs to their natal site (natal philopatry hypothesis) or habitat in which they were reared (habitat-imprinting hypothesis), there is a higher probability of finding nests of the host species by which they were reared. Since published evidence is ambiguous, we here evaluate the natal philopatry and habitat-imprinting hypotheses using information on habitat homogeneity and cross-continental long-term ringing data. We found no evidence for the natal philopatry hypothesis—instead of returning to their natal site, juvenile cuckoos exhibited longer dispersal movements than adults, and the difference was even larger in comparison with a wide array of cuckoo host species. On the contrary, we found support for the habitat-imprinting hypothesis—juvenile cuckoos followed similar levels of natal habitat homogeneity at 5- and 25-km scale when returning to breed in the next years. Our results suggest that preference for the particular habitat structures may help cuckoos to find appropriate hosts. [ABSTRACT FROM AUTHOR]