| population genetics and characterization of campylobacter jejuni isolates from western jackdaws and game birds in finland. | poultry are considered a major reservoir and source of human campylobacteriosis, but the roles of environmental reservoirs, including wild birds, have not been assessed in depth. in this study, we isolated and characterized campylobacter jejuni from western jackdaws (n = 91, 43%), mallard ducks (n = 82, 76%), and pheasants (n = 9, 9%). most of the western jackdaw and mallard duck c. jejuni isolates represented multilocus sequence typing (mlst) sequence types (sts) that diverged from those previo ... | 2019 | 30552190 |
| local interactions and their group-level consequences in flocking jackdaws. | as one of nature's most striking examples of collective behaviour, bird flocks have attracted extensive research. however, we still lack an understanding of the attractive and repulsive forces that govern interactions between individuals within flocks and how these forces influence neighbours' relative positions and ultimately determine the shape of flocks. we address these issues by analysing the three-dimensional movements of wild jackdaws ( corvus monedula) in flocks containing 2-338 individu ... | 2019 | 31266425 |
| genetic monogamy despite frequent extrapair copulations in "strictly monogamous" wild jackdaws. | "monogamy" refers to different components of pair exclusiveness: the social pair, sexual partners, and the genetic outcome of sexual encounters. avian monogamy is usually defined socially or genetically, whereas quantifications of sexual behavior remain scarce. jackdaws (corvus monedula) are considered a rare example of strict monogamy in songbirds, with lifelong pair bonds and little genetic evidence for extrapair (ep) offspring. yet jackdaw copulations, although accompanied by loud copulation ... | 2020 | 32372855 |
| exploring individual and social learning in jackdaws (corvus monedula). | information about novel environments or foods can be gathered via individual or social learning. whereas individual learning is assumed to be more costly and less effective than social learning, it also yields more detailed information. juveniles are often found to be more explorative than adults. still under the protection of their parents, this allows them to sample their environment in preparation for later in life. we tested individual and social learning in jackdaws (corvus monedula) of dif ... | 2019 | 31148101 |
| testing relationship recognition in wild jackdaws (corvus monedula). | according to the social intelligence hypothesis, understanding the challenges faced by social animals is key to understanding the evolution of cognition. in structured social groups, recognising the relationships of others is often important for predicting the outcomes of interactions. third-party relationship recognition has been widely investigated in primates, but studies of other species are limited. furthermore, few studies test for third-party relationship recognition in the wild, where co ... | 2019 | 31040366 |
| experimentally increased brood size accelerates actuarial senescence and increases subsequent reproductive effort in a wild bird population. | the assumption that reproductive effort decreases somatic state, accelerating ageing, is central to our understanding of life-history variation. maximal reproductive effort early in life is predicted to be maladaptive by accelerating ageing disproportionally, decreasing fitness. optimality theory predicts that reproductive effort is restrained early in life to balance the fitness contribution of reproduction against the survival cost induced by the reproductive effort. when adaptive, the level o ... | 2020 | 32037534 |
| behavioural plasticity and the transition to order in jackdaw flocks. | collective behaviour is typically thought to arise from individuals following fixed interaction rules. the possibility that interaction rules may change under different circumstances has thus only rarely been investigated. here we show that local interactions in flocks of wild jackdaws (corvus monedula) vary drastically in different contexts, leading to distinct group-level properties. jackdaws interact with a fixed number of neighbours (topological interactions) when traveling to roosts, but co ... | 2019 | 31729384 |
| correction to 'evidence for individual discrimination and numerical assessment in collective antipredator behaviour in wild jackdaws (corvus monedula)'. | | 2019 | 31690210 |
| collective turns in jackdaw flocks: kinematics and information transfer. | the rapid, cohesive turns of bird flocks are one of the most vivid examples of collective behaviour in nature, and have attracted much research. three-dimensional imaging techniques now allow us to characterize the kinematics of turning and their group-level consequences in precise detail. we measured the kinematics of flocks of wild jackdaws executing collective turns in two contexts: during transit to roosts and anti-predator mobbing. all flocks reduced their speed during turns, probably becau ... | 2019 | 31640502 |
| evidence for individual discrimination and numerical assessment in collective antipredator behaviour in wild jackdaws (corvus monedula). | collective responses to threats occur throughout the animal kingdom but little is known about the cognitive processes underpinning them. antipredator mobbing is one such response. approaching a predator may be highly risky, but the individual risk declines and the likelihood of repelling the predator increases in larger mobbing groups. the ability to appraise the number of conspecifics involved in a mobbing event could therefore facilitate strategic decisions about whether to join. mobs are comm ... | 2019 | 31573430 |
| comparative analysis of avian hearts provides little evidence for variation among species with acquired endothermy. | mammals and birds acquired high performance hearts and endothermy during their independent evolution from amniotes with many sauropsid features. a literature review shows that the variation in atrial morphology is greater in mammals than in ectothermic sauropsids. we therefore hypothesized that the transition from ectothermy to endothermy was associated with greater variation in cardiac structure. we tested the hypothesis in 14 orders of birds by assessing the variation in 15 cardiac structures ... | 2019 | 30667083 |
| free-ranging avifauna as a source of generalist parasites for captive birds in zoological settings: an overview of parasite records and potential for cross-transmission. | captive birds in zoological settings often harbor parasites, but little information is available about the potential for free-ranging avifauna to act as a source of infection. this review summarizes the gastrointestinal parasites found in zoo birds globally and in seven common free-ranging avian species [mallard (anas platyrhynchos), eurasian blackbird (turdus merula), common starling (sturnus vulgaris), eurasian jackdaw (corvus monedula), house sparrow (passer domesticus), european robin (erith ... | 2020 | 33005675 |
| gastrointestinal parasites in captive and free-ranging birds and potential cross-transmission in a zoo environment. | gastrointestinal parasites are commonly reported in wild birds, but transmission amongst avifauna in zoological settings, and between these captive birds and wild birds in surrounding areas, remains poorly understood. a survey was undertaken to investigate the occurrence of gastrointestinal parasites in captive and free-ranging birds at bristol zoo gardens between may and july 2016. a total of 348 fecal samples from 32 avian species were examined using the mini-flotac flotation method. parasites ... | 2018 | 29517437 |
| the expression of tyrosine hydroxylase and darpp-32 in the house crow (corvus splendens) brain. | birds of the family corvidae which includes diverse species such as crows, rooks, ravens, magpies, jays, and jackdaws are known for their amazing abilities at problem-solving. since the catecholaminergic system, especially the neurotransmitter dopamine, plays a role in cognition, we decided to study the distribution of tyrosine hydroxylase (th), the rate-limiting enzyme in the synthesis of catecholamines in the brain of house crows (corvus splendens). we also studied the expression of darpp-32 ( ... | 2019 | 30697741 |
| wild jackdaws are wary of objects that violate expectations of animacy. | nature is composed of self-propelled, animate agents and inanimate objects. laboratory studies have shown that human infants and a few species discriminate between animate and inanimate objects. this ability is assumed to have evolved to support social cognition and filial imprinting, but its ecological role for wild animals has never been examined. an alternative, functional explanation is that discriminating stimuli based on their potential for animacy helps animals distinguish between harmles ... | 2018 | 30473852 |
| simultaneous measurements of three-dimensional trajectories and wingbeat frequencies of birds in the field. | tracking the movements of birds in three dimensions is integral to a wide range of problems in animal ecology, behaviour and cognition. multi-camera stereo-imaging has been used to track the three-dimensional (3d) motion of birds in dense flocks, but precise localization of birds remains a challenge due to imaging resolution in the depth direction and optical occlusion. this paper introduces a portable stereo-imaging system with improved accuracy and a simple stereo-matching algorithm that can r ... | 2018 | 30355809 |
| caller characteristics influence recruitment to collective anti-predator events in jackdaws. | across the animal kingdom, examples abound of individuals coming together to repel external threats. when such collective actions are initiated by recruitment signals, individuals may benefit from being selective in whom they join, so the identity of the initiator may determine the magnitude of the group response. however, the role of signaller discrimination in coordinating group-level responses has yet to be tested. here we show that in wild jackdaws, a colonial corvid species, collective resp ... | 2018 | 29743545 |
| canalisation in the wild: effects of developmental conditions on physiological traits are inversely linked to their association with fitness. | ecological conditions affect fitness, but mechanisms causing such effects are not well known, while evolved responses to environmental variation may depend on the underlying mechanisms. consequences of environmental conditions vary strongly between traits, but a framework to interpret such variation is lacking. we propose that variation in trait response may be explained by differential canalisation, with traits with larger fitness effects showing weaker responses to environmental perturbations ... | 2018 | 29601669 |
| testing social learning of anti-predator responses in juvenile jackdaws: the importance of accounting for levels of agitation. | social learning is often assumed to help young animals respond appropriately to potential threats in the environment. we brought wild, juvenile jackdaws briefly into captivity to test whether short exposures to conspecific vocalizations are sufficient to promote anti-predator learning. individuals were presented with one of two models-a stuffed fox representing a genuine threat, or a toy elephant simulating a novel predator. following an initial baseline presentation, juveniles were trained by p ... | 2018 | 29410861 |
| regulation of hormonal control, cell reprogramming, and patterning during de novo root organogenesis. | body regeneration through formation of new organs is a major question in developmental biology. we investigated de novo root formation using whole leaves of arabidopsis (arabidopsis thaliana). our results show that local cytokinin biosynthesis and auxin biosynthesis in the leaf blade followed by auxin long-distance transport to the petiole leads to proliferation of j0121-marked xylem-associated tissues and others through signaling of indole-3-acetic acid inducible28 (iaa28), crane (iaa18), woode ... | 2018 | 29233938 |