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Quill mites are obligatory parasites of birds, widely distributed among their hosts. For the first time, we examined birds from two small, phylogenetically closely related piciform families, Megalaimidae (New World Barbets) and Capitonidae (Asian Barbets), for infestation by parasitic mites of the subfamily Picobiinae (Acariformes: Syringophilidae). Birds of the family Megalaimidae were infested by two new species of the genus Picobia: Picobia insolita Skoracki, Sikora & Unsoeld n. sp. collected from Caloramphus hayii in Indonesia, and Picobia paraheeri Skoracki, Sikora & Unsoeld n. sp. found on nine bird species of the genus Psilopogon, including P. zeylanicus in Sri Lanka, P. asiaticus in India, P. virens in China, P. franklini and P. lineatus both in Nepal, and P. corvinus, P. rafflesii, P. chrysopogon, P. pyrolophus, all in Indonesia. Within the Capitonidae family, a single quill mite species, Rafapicobia olszanowskii Skoracki et al. 2020, was found infesting two species of the genus Capito, i.e. C. maculicoronatus in Panama and C. niger in Surinam and Guyana, and these two Asian Barbet species are new hosts for this quill mite species. Our further analysis of picobiine mite records associated with the entire order of Piciformes revealed a correlation between the mites' distribution patterns and the phylogeny of piciform birds. This significant congruence suggests a close evolutionary relationship between picobiine mites and their avian hosts. [ABSTRACT FROM AUTHOR]

Birds select breeding territories by assessing territory quality and considering predation pressure. However, in many small passerines, brood parasitism may also play an important role in territory occupancy. Settlement decisions are made under time pressure, especially for late migrants. An example of late migrants is the red-backed shrike Lanius collurio, a species wintering in sub-tropical Africa, which serves as a host for the common cuckoo Cuculus canorus and arrives in territories a few days later than their brood parasite. We expected that arriving red-backed shrikes avoided territories with common cuckoo presence. Then, we tested how experimentally provided artificial playback calls of the common cuckoo and woodpigeon (treated as control) affected the probability of red-backed shrike settlement. In the breeding season 2021, we observed 279 red-backed shrike territories to assess the effect of playback of common cuckoo calls on their host presence. Moreover, we adopt information on shrike territories collected in previous years to establish territory quality, measured by occupancy pattern over years. Each of these places was also checked for the presence of corvids, which are predators of shrike nests. We did not find difference with lower preference of shrikes towards cuckoo calls and to pigeon calls Columba columbus, what suggest the human presence and manipulation in the territories during experiments with recorders should be incorporated as an important factor to understanding shrikes' settlement behaviour. What is interesting we found no negative effect of corvids (jay Garrulus glandarius) in control territories. However, shrike territories where cuckoo calls were emitted and where the presence of corvids was found were less likely to be inhabited by shrikes. Therefore, territory quality, human presence enhanced by nest predators, is an important factor affecting host–parasite interactions. [ABSTRACT FROM AUTHOR]

The mite family Syringophilidae (Acariformes: Prostigmata) includes permanent parasites of birds exclusively, occupying their quill feathers where they reproduce and feed on living tissue fluids, piercing the quill-wall with their long and stiletiform chelicerae. The Boreal Owl, Aegolius funereus (L.) (Strigiformes: Strigidae) is parasitised by the Bubophilus aegolius, which is a new species of syringophilid mite described herein. In our study a total of 55 Boreal Owls were examined, including birds from Poland, Austria, Switzerland, Germany, Czechia, Slovakia, Sweden, Finland, and Norway. A total of four host specimens from Poland, Switzerland, and Finland were infested by Bubophilus aegolius (index of prevalence IP = 7.3; 95% confidence interval for prevalence (Sterne's method) CI = 2.5–17.9). In the material consisting of 14 juvenile (in the 1st calendar year) and 41 adults (in the 2nd calendar year or older) birds, only juvenile hosts were infested (IP = 28.6%; CI = 10.4–57.4). Among 3,190 examined feathers (primaries (N = 1,100), secondaries (N = 1,430), rectrices (N = 660), quill mites were found only in four feathers, each feather from a single host specimen: in two small secondaries, S12, S13, and in two middle rectrices R1. This low prevalence may be related to the solitary behaviour of owls and the marginal role of horizontal transfers of parasites between hosts. Hypothetically, the low number of infested feathers on the host indicates low effectiveness (= high mortality) during transmission, where – in each case – only one fertilised female foundress (dispersal stage) was able to transfer from the parent to the offspring and enter a new quill feather. [ABSTRACT FROM AUTHOR]

The northern hawk owl is a real irruptive species that respond to irregular changes in the food supply. When prey levels are adequate, it breeds and winters within northern forests. Decreased prey availability can start winter invasions, the timing and magnitude of which are the subject of this study. Mainly the citizen data were extracted from the national bird websites to obtain data on the number of northern hawk owls observed in 2010–22. This paper demonstrates that through citizen data large amounts of information can be collected over wide areas, entire Europe in this case.

Farmland landscapes are recognized as important ecosystems, not only for their rich biodiversity but equally so for the human beings who live and work in these places. However, biodiversity varies among sites (spatial change) and among seasons (temporal change). In this work, we tested the hypothesis that bird diversity hotspots distribution for breeding is congruent with bird diversity hotspots for wintering season, focusing also the representation of protected areas for the conservation of local hotspots. We proposed a framework based on the use of species richness, functional diversity, and evolutionary distinctiveness to characterize avian communities.

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The paper presents the results of studies on the distribution of the parasitic quill mite species Bubophilus aluconis (Acariformes: Syringophilidae) in the feather quills of the Western Palaearctic owls of the genus Strix , that is, tawny owl S. aluco , collected in Poland and Sweden, the Ural owl S. uralensis , from Poland, Sweden, and Finland, and the great grey owl S. nebulosa , from Sweden and Finland. The two latter species are new hosts for B. aluconis . Methods: Feather samples of the tawny owl, Ural owl, and great grey owl used in this study come from Prof. Marian Cieślak's private collection, which contains feathers of Western Palearctic birds of prey and owls. Each of the 77 tawny owl, 75 Ural owl, and 55 great grey owl specimens are represented either by whole dry wings or a full complement of flight feathers (primaries (P) and secondaries (S)) and tails (rectrices (R)). Particular types of feathers were coded as follows: Ps, Ss, R, primary greater upperwing coverts (PGUppC), secondary greater upperwing coverts (SGUppC), primary greater underwing coverts (PGUndrC), secondary greater underwing coverts (SGUndrC), uppertail coverts (UppTC), and undertail coverts (UndrTC). Results: The prevalence was relatively low for all of the examined birds, that is, 12% for S. uralensis ( N = 79), 2.6% for S. aluco ( N = 77), and 3.6% for S. nebulosa ( N = 55). In total, we examined 37,260 flight feathers and coverts. The mite B. aluconis occupied only the inner S of the tawny owl, secondary greater under and upperwing coverts of the great grey owl, and inner Ss, primary and secondary upperwing coverts, UndrTC, and coverts from the scapulars of the Ural owl. Conclusion: We hypothesise that the absence of these parasites in the examined P, S, and R suggests that these feather types might be unsuitable for the mites due to their thick quill walls, preventing successful feeding., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Zbigniew Kwieciński et al.)

The appropriate structure of the digestive tract is crucial for individual adaptation to ecological conditions. In birds, the length of the small intestine, responsible for food absorption, is generally believed to be positively correlated with body size. In this study, we investigated the variation in small intestine length in the White Stork (Ciconia ciconia), a monomorphic species without visible sexual dimorphism, but characterized by differing parental efforts, which can be reflected by the small intestine lengths between the sexes. We examined the relationship between small intestine length and body size within the sexes. Our findings show that male White Storks have significantly shorter small intestines than females, despite having larger body sizes than the latter. Furthermore, we found a significant relationship between body size and small intestine length, but it was of a different nature in the two sexes. Males exhibited a previously unreported phenomenon, whereby increasing body size was associated with shortening small intestines, whereas females exhibited the opposite pattern. These novel findings shed light on the anatomical adaptations of the digestive tract in birds., (© 2024. The Author(s).)

Farmland birds belong to the most endangered group of vertebrates in Europe. They are an important component of farmland biodiversity considering the numerous functions they perform (e.g. seed dispersal, improving germination, increasing gene flow, nutrient recycling, and pest control). Therefore, their decline imposes substantial risks on agricultural ecosystems. In general, farmland bird conservation includes land-use and management alterations leading to less-intensive farming and land-sparing for breeding habitats (e.g. agri-environment-climate schemes, and organic farming). However, theoretical concepts describing farmland biodiversity maintenance and applied conservation measures usually ignore the role of singular, often very small, natural or man-made elements in an agricultural landscape. These elements play a role in the populations of certain species, their biology and in the general species richness of farmland. Furthermore, the importance of these elements has never been empirically tested, which means that conservationists and practitioners are not aware of their measurable value for birds. Herein, we define and identify singular point elements in the agricultural landscape (SPELs) which are potentially important for breeding farmland birds. We also describe each SPEL and evaluate its importance for birds in farmland based on a systematic review of the available literature. Using a horizon-scanning technique, we then polled field ornithologists about their personal observations of birds in relation to SPELs and the evaluation of the potential roles of such structures for birds. We identified 17 SPELs that vary in naturalness and age: singular trees, singular shrubs, erratic boulders, puddles, electricity pylons, wind turbines, spiritual sites, hunting platforms, fence and border posts, wells, road signs, scarecrows, piles of manure, piles of brushwood/branches, piles of stones/debris, piles of lime, and haystacks. Analysis of the literature revealed knowledge gaps, because some SPELs are frequently mentioned in ecological studies (e.g. trees, shrubs, pylons), but others such as spiritual sites, stones, hunting platforms, wells, road signs, or piles of lime are ignored. Despite the fact that some authors incorporate the effects of some SPELs in their studies, little research to date has aimed to assess the impact of various SPELs on farmland bird species numbers and distribution. Horizon scanning revealed that ornithologists often observe birds on various SPELs and thus, attribute to SPELs many functions that are important for maintaining bird populations. Horizon scanning also highlighted the importance of SPELs for many declining bird species and suggested possible mitigation of negative changes in the agricultural landscape by retaining SPELs within fields. We suggest that a better understanding of the role of SPELs for farmland birds is required. We also recommend that SPELs are considered as a potential tool for the conservation of birds, and existing conservation programs such as agri-environment-climate schemes and organic farming should be updated accordingly. Finally, we suggest that SPELs are included in predictive models that evaluate habitat suitability for farmland biodiversity., (© 2021 Cambridge Philosophical Society.)

Although shell colour polymorphism of the land snail Cepaea nemoralis is a well-known phenomenon, proximate and ultimate factors driving its evolution remain uncertain. Polymorphic species show variation in behavioural responses to selective forces. Therefore, we estimated effects of various environmental factors (temperature, humidity, food availability, (micro)habitat structure and predatory pressure) on behavioural response (frequency of locomotion, climbing and hiding) of C. nemoralis morphs, in experimental and natural conditions. In the experimental part of study, the frequency of locomotion was negatively affected by temperature and the presence of food and positively influenced by the presence of light. Morphs significantly differed in behavioural responses to environmental variability. Pink mid-banded and yellow five-banded morphs climbed less often and hide in shelter more often than yellow and pink unbanded individuals when temperature was low and food was absent. Snails fed most often at moderate temperature compared to low and high temperatures. Field investigations partially confirmed differences among morphs in frequency of climbing, but not in terms of probability of hiding in sheltered sites. In natural colonies, temperature and (micro)habitat structure significantly affected frequency of climbing as well as hiding in shelter. Snails more often hid in sheltered sites where thrushes preyed on Cepaea. Tendency of unbanded morphs to climb trees may have evolved under avian predatory pressure as thrushes forage on a ground. Tendency of banded morphs to hide in sheltered sites may reflect prey preferences for cryptic background. The results implicate that differential behaviour of C. nemoralis morphs compensate for their morphological and physiological limitations of adaptation to habitat.

Sex differences in the foraging ecology of monomorphic species are poorly understood, due to problems with gender identification in field studies. In the current study, we used experimental conditions to investigate the food preferences of the white stork Ciconia ciconia, an opportunistic species in terms of food, but characterised by a low level of sexual dimorphism. During a 10-day experiment, 29 individuals (20 females and 9 males) were studied by means of a 'cafeteria test' in which the storks' diet consisted of mammals, birds, fish, amphibians, insects and earthworms. The storks preferred food characterised by high calorific and protein values such as mammals, birds and fish. Sexes differed strongly in their preferences; males preferred mammals, whereas females preferred birds. Moreover, females consumed insects and earthworms less often than males. Interestingly, males spent significantly less time foraging than females. We have demonstrated that the white stork exhibits clear sexual differences in food preferences which are mostly attributable to differences in parental duties, physiology and anatomy.

Every species has certain habitat requirements, which may be altered by interactions with other co-occurring species. These interactions are mostly ignored in predictive models trying to identify key habitat variables correlated with species population abundance/occurrence. We investigated how the structure of the urban landscape, food resources, potential competitors, predators, and interaction between these factors influence the abundance of house sparrow Passer domesticus and the tree sparrow P. montanus in sixty 25 ha plots distributed randomly across residential areas of the city of Poznań (Poland). The abundance of the house sparrow was positively correlated with the abundance of pigeons but negatively correlated with human-related food resources. There were significant interaction terms between abundances of other urban species and habitat variables in statistical models. For example, the abundance of house sparrow was negatively correlated with the abundance of corvids and tree sparrows but only when food resources were low. The abundance of tree sparrows positively correlated with density of streets and the distance from the city center. The abundance of this species positively correlated with the abundance of corvids when food resources were low but negatively correlated at low covers of green area. Our study indicates that associations between food resources, habitat covers, and the relative abundance of two sparrow species are altered by the abundance of other urban species. Competition, niche separation and social facilitation may be responsible for these interactive effects. Thus, biotic interactions should be included not only as an additive effect but also as an interaction term between abundance and habitat variables in statistical models predicting species abundance and occurrence.

The nutcracker Nucifraga caryocatactes belongs to a group of bird species that use their beak and tongue as tools for obtaining food, such as seeds from hard-to-reach cones or nuts from shells. The aim of the present study, carried out with a scanning electron microscope, was to define the morphological features of the tongue of the nutcracker, which seems to be adapted to its environment through specific methods of obtaining food. One of the characteristic features of the nutcracker's tongue is the unique structure of the anterior part of the tongue, which has two long and highly keratinized processes - a product of the renewable keratinized layer of the epithelium covering the ventral surface of the tongue. These dagger-like processes, which are a modified "lingual nail," take a major role in levering up and shelling seeds, which are transported over the short sulcus-shaped body of the tongue. A unique feature of the nutcracker's tongue is the groove separating the body from the root. Two rows of highly keratinized, mechanical, conical papillae are located at the junction of the body and the root. These papillae are mechanically protective elements for passing food particles in the form of seeds. Among lingual glands, only the posterior lingual glands on the root of the tongue have been observed. Their secretion agglutinates dry food before it is swallowed. Results of the present study indicate that the nutcracker's tongue is an efficient tool resembling a lever that is helpful in shelling seeds.

Sex differences in digestive performance may be related to food contents, to body size as well as many other physiological traits. However, evidence for sex differences in the digestion of birds, especially in the case of predators, is scarce. Therefore we studied digestive efficiency, and also body size, intestine length and food selection of the wild white stork (Ciconia ciconia), under experimental conditions in the Poznań Zoo. Altogether 29 individuals of this species were investigated (9 males, 20 females). During 5-day- long experimental cycles, the diet of the birds consisted of mammals, birds, fishes and insects. The mean daily wet food intake (weight of the food eaten) during the experiment was 272.8g +/- 89.3 g for males and 342.7g +/- 157.4 g for females, but the difference between sexes was not significant (P = 0.226). The mean digestive efficiency showed a significant difference, i.e. in male white storks it amounted to 70.87% +/- 14.43%, whereas in females this value was 77.53% +/- 3.99% (P = 0.049). Digestive efficiency was slightly influenced by changes in body weight of storks during the experiment. Correlation coefficients between sexes also differed significantly (P = 0.037). The study showed that the digestive efficiency is positively correlated with the quantity of food intake and body weight.