The risk of nest predation differs across habitats and increases with proximity to habitat edges. In agricultural mosaic landscapes, the breeding success of ground-nesting birds can be negatively impacted by the presence of adjacent forest patches, which act as a source of predation. However, we still have limited knowledge on how birds nesting in such habitats cope with variable predation risk. In this study, we investigated predation rates of experimental ground nests and Northern Lapwing nests (Vanellus vanellus), in relation to the nearest patch. Furthermore, we tested the aggressive responses displayed by nesting pairs towards stuffed nest predators of different guilds at different distances from the forest. Predation rate on experimental nests increased with proximity and area of the closest forest patch. In contrast, predation rate on lapwing nests was not affected by the presence of forest, suggesting effective nest defence performed by parents to protect their clutch. Pairs displayed more aggressive behaviours against predators compared with a control wood log. Additionally, responses to specific predators varied with forest distance. Lapwings appeared more aggressive towards a bird when closer to forests, but were more aggressive towards a mammal further from forests. This study highlights the importance of fine-scale differences in anti-predatory behaviours to compensate for local variations in predation risk, in heterogeneous agricultural landscapes.

The Great Spotted Woodpecker (Dendrocopos major, MAJ) and the Middle Spotted Woodpecker (Dendrocoptes medius, MED) are ecologically similar species that co-occur in Central Europe and may compete for resources. Both forage on tree trunks and branches and excavate nest holes in trunks. While MAJ is a widespread generalist, MED is typically associated with old oak (Quercus) stands, though it has recently expanded into new habitats. We experimentally examined the dynamics of their interspecific competition comparing situations 20 years old and recent. We used experimental observations of induced aggression and territoriality, and ecological niche characterisation as methods for assessing the competition. Over the last two decades, MAJ’s aggression towards MED has decreased at long-term sympatric sites, suggesting behavioural adjustment. By contrast, MED’s aggression towards MAJ remained stable. Additionally, recent regional differences in interspecific aggression emerged: in sympatric regions, interspecific aggression was very low, whereas in areas where MED has only recently spread, MAJ displayed territorial behaviour towards it. Niche analyses revealed significant recent overlap, with MED’s niche entirely embedded within that of MAJ. We conclude that, despite niche overlap, MAJ has adapted to coexist with MED, whilst MED continues to perceive MAJ as a competitor. This asymmetric dynamic highlights how generalist species may adjust their behavioural strategies to accommodate expanding specialists, whilst specialists may maintain more rigid responses, potentially limiting their competitive flexibility in changing ecosystems.

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.

Bioacoustic parameters of vocalization are generally well adapted to the environment that the species inhabits and are influenced by the morphology and life history of the species. These effects are frequently studied on bird songs; however, little is known about how ecology, phylogeny and morphology affect alarm calls. We investigated these factors in the crow family (Corvidae, Passeriformes) that exhibits extensive distribution around the world and is well known for their variable, conspicuous alarm calls. Using a free database of sounds (xeno-canto) as well as own recordings, we collected alarm calls of 66 species representing 21 out of 24 genera within the family. We measured four vocal characteristics, which showed high variability among the family and low mutual correlation – peak frequency, peak frequency change, harmonicity and call duration. The effect of body mass and preferred habitat openness of the species on these four parameters was tested using phylogenetic regression. We also assessed the strength of the phylogenetic signal. Peak frequency, peak frequency change and harmonicity were influenced by phylogeny, while the alarm call duration evolved independently of phylogeny. Body mass significantly affects the mean peak frequency with bigger species producing sounds of lower frequency. Additionally, the openness of the preferred habitat of the species significantly affects the maximum change in peak frequency. Forest species show less peak frequency fluctuation within the alarm call, probably because dense vegetation does not favour good transmission of highly modulated signals. We conclude, that features of corvid alarm calls are affected by similar drivers as e.g. bird song.

Neophobia, or aversion to novelty, is important for adaptability and survival as it influences the ways in which animals navigate risk and interact with their environments. Across individuals, species and other taxonomic levels, neophobia is known to vary considerably, but our understanding of the wider ecological drivers of neophobia is hampered by a lack of comparative multispecies studies using standardized methods. Here, we utilized the ManyBirds Project, a Big Team Science large-scale collaborative open science framework, to pool efforts and resources of 129 collaborators at 77 institutions from 24 countries worldwide across six continents. We examined both difference scores (between novel object test and control conditions) and raw data of latency to touch familiar food in the presence (test) and absence (control) of a novel object among 1,439 subjects from 136 bird species across 25 taxonomic orders incorporating lab, field, and zoo sites. We first demonstrated that consistent differences in neophobia existed among individuals, among species, and among other taxonomic levels in our dataset, rejecting the null hypothesis that neophobia is highly plastic at all taxonomic levels with no evidence for evolutionary divergence. We then tested for effects of ecological factors on neophobia, including diet, sociality, habitat, and range, while accounting for phylogeny. We found that (i) species with more specialist diets were more neophobic than those with more generalist diets, providing support for the Neophobia Threshold Hypothesis; (ii) migratory species were also more neophobic than nonmigratory species, which supports the Dangerous Niche Hypothesis. Our study shows that the evolution of avian neophobia has been shaped by ecological drivers and demonstrates the potential of Big Team Science to advance our understanding of animal behavior.

The composite perception of individual elements and their configurations on the face during its recognition, so-called holistic processing, has been demonstrated in humans and some animals. However, it is unknown whether similar processes apply, at least to some extent, to the recognition of ecologically relevant stimuli by birds. The important role of facial elements (hooked beak and conspicuous eye color) in recognizing avian predators has been repeatedly demonstrated. However, no attention has yet been paid to the importance of their configuration (i.e., the mutual position of the eyes and beak). We tested the ability of untrained wild great tits to recognize a dangerous predator with its eyes rotated by 90° around its beak (inline dummy) and by 180°around its beak (invert dummy) in an outdoor aviary experiment. A dummy of a sparrowhawk with its head devoid of eyes and beak (empty dummy) served as a behavioral baseline alongside dummies of an unmodified sparrowhawk and a pigeon (as a harmless control). The tits showed no more fear toward the empty dummy than they did toward the pigeon. Toward the invert dummy, the tits showed no less fear than toward the unmodified sparrowhawk. By contrast, in the case of the inline modification, their behavior can be interpreted as increased fear. Our results do not prove that tits use holistic processing in predator recognition, but sensitivity to the presence and configuration of facial elements in the predator's face suggests that this possibility should not be ruled out. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

The ability of terrestrial isopods (Crustacea: Isopoda: Oniscidea) to protect themselves effectively from predation by birds has never been tested. They are equipped with glands producing chemical substances; moreover, some species show conspicuous coloration, which might suffice as an aposematic signal. We evaluated the palatability of isopods to birds. We tested the responses of Parus major captured in the wild (and thus possessing some experience with common native isopod species) to the following isopod species: Porcellio scaber (native, inconspicuous), Oniscus asellus (native, moderately conspicuous), Armadillo officinalis (non-native, moderately conspicuous), Armadillidium versicolor (native, conspicuous), and Armadillidium gestroi (non-native, conspicuous). We compared bird responses to isopods with reactions to the Blaptica dubia, an edible roach very similar to isopods in size and appearance. Isopods were better protected from bird attacks than roaches; however, their color pattern did not affect the level of protection. Birds were able to differentiate isopods from the roach; in experiments, where we presented isopod and roach individuals together, the birds hesitated longer in attacking and observed both prey items for a longer time. Non-native species either profited from the generalization of the protection of native isopods or from neophobia. Some isopods elicited significantly more discomfort behavior in birds, suggesting differences in the chemical protection among the tested species.

Shorebirds experience high rates of nest predation due to their ground-nesting, leading to diverse antipredator behaviors to mitigate this risk. Accurate predator recognition enables birds to adjust their responses, employ effective nest defense strategies, and conserve time and energy. In this study, we selected the Common Ringed Plover (Charadrius hiaticula) as a model species to examine predator recognition and adjustment of nest defense. The plover’s defense includes nest camouflage and distraction displays. We evaluated its ability to recognize predators and its responses to species posing varying levels of threat to the clutch and parents. To achieve this, we conducted experiments using dummies accompanied by the calls of the respective species representing the Parasitic Jaeger (Stercorarius parasiticus) and the Eurasian Magpie (Pica pica) as nest predators, the Merlin (Falco columbarius) as an adult predator, the European Golden Plover (Pluvialis apricaria) as a harmless species, and a wooden log as a control baseline. The Common Ringed Plover demonstrated a strong ability to assess potential threats. The Parasitic Jaeger was recognized as the most threatening, eliciting distraction displays and alarm calls. The Magpie elicited a weaker response, possibly due to the plover’s limited experience with it as a nest predator, as magpies rarely forage in its breeding habitats. The response to Merlin was surprisingly low, comparable to the baseline, suggesting that plovers relied rather on the concealment strategy and were hesitant to fly away. Counterintuitively, the plovers did not treat the European Golden Plover as harmless, indicating potential interspecific interactions between these species.

1. The harlequin ladybird (Harmonia axyridis) shows a high level of colour polymorphism. Particular forms differ in their colour combination, pattern and abundance.2. Two species of wild-caught passerines native to Central Europe were offered various forms of ladybirds, differing in their colour pattern and abundance in nature. We predicted that those forms that are more abundant in the wild are better protected, as they are more familiar to predators.3. Forms novemdecimsignata and spectabilis, which represent 97% of individuals in the wild population, significantly differ in their visual appearance (mostly orange vs. mostly black). The form axyridis is very rare in the wild, and suturalis and aninkae do not occur in the wild and were derived from laboratory breedings4. As predators, we used great tits (Parus major), which are very aversive towards ladybirds, and tree sparrows (Passer montanus), which are quite willing to attack and even eat ladybirds.5. We compared bird responses to particular ladybird colour forms and included a brown-painted control to test the effect of conspicuous colours.6. We showed that both species of birds attacked all conspicuous forms of the ladybird equally and usually very rarely. The brown-painted novemdecimsignata form was attacked more frequently compared with the conspicuous forms, showing that the visual appearance prevents birds from attacking any conspicuous colour combination. Sparrows tended to eat the attacked ladybirds of forms novemdecimsignata, spectabilis and brown painted. The rare axyridis form and laboratory forms were very well protected from the attack, very likely due to neophobia.7. We may conclude that despite the outstanding polymorphism of H. axyridis, its protection against avian predators is very effective as long as the red-and-black pattern is preserved.

An integral characteristic of all predators is their size, which affects, among other things, their food preferences, and the ability of their prey to fight them off. Several studies have already found, unsurprisingly, that birds discriminate between and respond differently to predators of different sizes. The red-backed shrike, Lanius collurio, aggressively attacks the Eurasian jay, Garrulus glandarius, a common nest predator, whereas it remains passive towards the carrion crow, Corvus corone, which also commonly plunders passerine nests. A possible explanation may reside in the larger body size of crows. In our experiments, we exposed red-backed shrikes to downsized crow dummies and enlarged jay dummies. The shrikes responded to the largest jays with less aggression, suggesting that aggression towards the largest jays would increase risk of injury to parent shrikes and/or not increase the likelihood of offspring survival. In contrast, aggression increased only slightly towards the crows with reduced size. Thus, there was no general effect of body size on the attack rate of shrikes to the presented dummies. In the case of the crow, an alternative antipredator strategy, guarding and not attacking the predator, might affect the behaviour of some shrike parents. These results suggest that body size is one of the key parameters in the recognition of predators by red-backed shrikes, but it is evaluated differently in nest defence against two distinct predator species.

Multiple raptors show juvenile plumage that is substantially different from that of their parents. Here, we test the prediction that the colouration of the juvenile northern goshawk Accipiter gentilis resembling the colouration of the common buzzard Buteo buteo acts as a form of aggressive mimicry. The goshawk specialises in hunting larger birds and mammals up to the size of geese or hares, while the buzzard preys mostly on small rodents. Larger birds may thus consider juvenile goshawks as less dangerous raptors, and the juvenile goshawk may thus gain an advantage when hunting. We used the Eurasian magpie Pica pica , a common prey of the goshawk, to test this prediction. We compared the behavioural responses of magpie parents defending their freshly fledged young towards mounts of an adult goshawk, juvenile goshawk, and buzzard. To be able to assess whether this behaviour differs from responses to a nest predator and a harmless bird we also presented a common raven Corvus corax and common pheasant Phasianus colchicus as baseline stimuli. Both juvenile and adult goshawks elicited antipredatory behaviour, but magpies took more risks facing juvenile goshawks. Additionally, the intensity of antipredatory behaviour towards the juvenile goshawk was also higher than towards the buzzard. We thus conclude that magpies do distinguish between juvenile and adult goshawks, as well as they do distinguish juvenile goshawks from buzzards. They are able to assess the threat particular raptors represent and respond accordingly. Analysis of spectral reflectance of stuffed specimens of these three raptors suggests there are differences, which can be used for the appropriate recognition. In conclusion, we cannot confirm the hypothesis of aggressive mimicry in juvenile goshawks that interact with magpies.

A formulation of the equations of motion phonon method (EMPM) suited for hypernuclei is outlined and illustrated through an application to B ∧ 12 . A self-consistent calculation using realistic modern potentials is performed using a multiphonon basis which enables us to couple the Λ-particle-proton-hole (pΛ - h) Tamm-Dancoff (TDΛ) states to the excitations of the nuclear core. The impact of such a coupling on the energy levels and on the electroproduction cross section of B ∧ 12 suggests that complex configurations accounting for the excitation of the nuclear core are needed for approaching the experimental data.

We investigate the differences and analogies between the equation of motion phonon method (EMPM) and second Tamm-Dancoff and random-phase approximations (STDA and SRPA) paying special attention to the problem of spurious center-of-mass (c.m.) admixtures. In order to compare them on an equal footing, we perform self-consistent calculations of the multipole strength distributions in selected doubly magic nuclei within a space including up to two-particle-two-hole (2p-2h) basis states using the UCOM two-body intrinsic Hamiltonian and we explore the tools each approach supplies for removing the spurious c.m. admixtures. We find that the EMPM and STDA yield exactly the same results when the same intrinsic Hamiltonian is used and the coupling of the Hartree-Fock state with the 2p-2h space is neglected, but, unlike STDA and SRPA, the EMPM offers the possibility to completely remove c.m. admixtures.

The electroproduction of selected $p$- and $sd$-shell hypernuclei was studied within a many-body approach using realistic interactions between the constituent baryons. The cross sections were computed in distorted-wave impulse approximation using two elementary amplitudes for the electroproduction of the $\Lambda$ hyperon. The structure of the hypernuclei was investigated within the framework of the self-consistent $\Lambda$-nucleon Tamm-Dancoff approach and its extension known as the $\Lambda$-nucleon equation of motion phonon method. Use was made of the NNLOsat chiral potential plus the effective Nijmegen-F YN interaction. The method was first implemented on light nuclei for studying the available experimental data and establishing a relation to other approaches. After this proof test, it was adopted for predicting the electroproduction cross section of the hypernuclei $^{40}_{~\Lambda}$K and $^{48}_{~\Lambda}$K in view of the E12-15-008 experiment in preparation at JLab. On the ground of these predictions, appreciable effects on the spectra are expected to be induced by the YN interaction.

We report on an upgraded version of the equation of motion phonon method (EMPM) which exploits the singular value decomposition (SVD) of rectangular matrices to decouple completely and exactly the intrinsic from the center of mass (c.m.) translational motion under no restrictions and for an arbitrary single particle (s.p.) basis. Its numerical implementation on 4 He illustrates the way such a decoupling is achieved and its important effects on spectra and nuclear response functions.

Bulk properties, spectrum, and nuclear response of 8He are investigated within the equation of motion phonon method, which generates an orthonormal basis of n-phonon states (n = 0, 1, 2, 3 ...) whose constituents are Tamm-Dancoff phonons. The basis is free of any contamination induced by the center-of-mass motion, in virtue of a procedure exploiting the singular value decomposition of rectangular matrices. A self-consistent calculation is performed within a space spanned by a basis of n-phonon states up to n = 3 using a potential derived from the chiral effective field theory. The Hartree-Fock single-particle states are obtained from a harmonic-oscillator space including all major shells up to Nmax= 12. The calculation is exact up ton = 2, whereas the three-phonon (n = 3) states are assumed to be composed of noninteracting n = 1 and n = 2 constituent phonons. It yields bulk and spectroscopic observables consistent with the available experimental data and provides an electric dipole response exhibiting distinctive signatures.

Bulk and spectroscopic properties of 4He are studied within an equation of motion phonon method. Such a method generates a basis of n-phonon (n = 0, 1, 2, 3...) states composed of tensor products of particle-hole Tamm-Dancoff phonons and then solves the full eigenvalue problem in such a basis. The method does not rely on any approximation and is free of any contamination induced by the center of mass, in virtue of a procedure exploiting the singular value decomposition of rectangular matrices. Two potentials, both derived from the chiral effective field theory, are adopted in a self-consistent calculation performed within a space including up to three phonons. The latter basis states are treated under a simplifying assumption. A comparative analysis with the experimental data points out the different performances of the two potentials. It shows also that the calculation succeeds only partially in the description of the spectroscopic properties and suggests a recipe for further improvements.

The aim of the study was to evaluate early postoperative results of different surgical techniques of aortic root surgery. Material and methods. Between January 2004 and November 2007, a cohort of 83 patients underwent aortic root surgery in the Heart Center, Hospital of Kaunas University of Medicine. Patients were divided into three groups: Group 1 (18 patients) – reimplantation of the aortic valve within a vascular graft (David operation), Group 2 (48 patients) – replacement of the ascending aorta and aortic valve using a valved conduit (Bentall de Bono operation), and Group 3 (17 patients) – biological aortic root replacement. Study protocol included clinical data, operative data, and postoperative major adverse effects: reoperations for bleeding, stroke and lethal outcomes. Results. Patients undergoing biological aortic root replacement were older as compared with other groups. The mean age in the Group 1 was 50.3±3.5 years vs. 57±2.0 years in the Group 2 and 67.8±3.3 years in the Group 3 (P<0.05). The main indication for the aortic root surgery was the aneurysm of the aortic root and ascending aorta in the Group 1 and 2 patients (64.7% and 72%), while in the Group 3, the main indication was fibrocalcinosis of aortic valve, aortic annulus, and ascending aorta (61.1%). The 30-day hospital mortality rates were as follows: 5.8% (n=1), in the Group 1; 10.4% (n=5), in the Group 2; 5.5% (n=1), in the Group 3. In the early postoperative period, 11 reoperations were performed due to bleeding events: in the Group 1, after planned/emergency surgery (n=2/2), and in the Group 2 (n=1/6), respectively. The function of aortic valve improved significantly in all groups of patients early after surgery. In the Group 1, the degree of aortic regurgitation decreased from 2.5±0.8 to 1.1±0.6 (P<0.05); in the Groups 2 and 3, the mean gradient through the aortic valve decreased from 39.9±7.5 to 17.1±5.3 mm Hg and from 48.8±18.0 to 20.1±11.0 mm Hg, respectively (P<0.05). No reoperation for aortic valve failure before the discharge was required in all groups of patients, and neither thromboembolic complications nor stroke events were noted in any group. Conclusions. Different aortic root surgery techniques showed similar postoperative results. New aortic root surgery methods such as aortic root-preserving/sparing procedures and concurrent aortic valve leaflet repair or aortic root replacement with the bioprosthesis can be selected for a diverse class of aortic root pathology with low perioperative mortality rates and good early postoperative results.

We present two methods, the Nucleon-Lambda Tamm Dancoff Approximation (NΛ TDA) and the Equation of Motion Phonon Method (EMPM) suitable for calculating hypernuclear energy spectra and structure. These methods are applicable for hypernuclei of wide range of masses with one Λ particle replacing one nucleon in an even-even nuclear cores. Using an effective Lambda-nucleon (ΛN) potential both methods were applied to calculate the energy spectrum of 12ΛB and also one body density matrix elements (OBDME). The OBDME were applied to calculate the electroproduction cross section of 12ΛB. We obtained better agreement with the experimental data by using EMPM than NΛ TDA. We plan to provide theoretical prediction (by applying the same methods and ΛN potentials) of the cross section in electroproduction of 40ΛK and 48ΛK.

In a previous analysis of electroproduction of hypernuclei the cross sections were calculated in distorted-wave impulse approximation where the momentum of the initial proton in the nucleus was set to zero (the frozen-proton approximation). In this paper we go beyond this approximation assuming a non zero effective proton momentum due to proton Fermi motion inside of the target nucleus discussing also other kinematical effects. To this end we have derived a more general form of the two-component elementary electroproduction amplitude (Chew-Goldberger-Low-Nambu like) which allows its use in a general reference frame moving with respect to the nucleus-rest frame. The effects of Fermi motion were found to depend on kinematics and elementary amplitudes. The largest effects were observed in the contributions from the longitudinal and interference parts of the cross sections. The extension of the calculations beyond the frozen-proton approximation improved the agreement of predicted theoretical cross sections with experimental data and once we assumed the optimum on-shell approximation, we were able to remove an inconsistency which was previously present in the calculations.