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extraordinary large brains in tool-using new caledonian crows (corvus moneduloides).a general correlation exists between brain weight and higher cognitive ability in birds and mammals. in birds this relationship is especially evident in corvids. these animals are well-known for their flexible behavior and problem-solving abilities, and have relatively large brains associated with a pallial enlargement. at the behavioral level, new caledonian crows stand out amongst corvids because of their impressive object manipulation skills both in the wild and in the laboratory. however, no ...200818262356
eurasian jays do not copy the choices of conspecifics, but they do show evidence of stimulus enhancement.corvids (birds in the crow family) are hypothesised to have a general cognitive tool-kit because they show a wide range of transferrable skills across social, physical and temporal tasks, despite differences in socioecology. however, it is unknown whether relatively asocial corvids differ from social corvids in their use of social information in the context of copying the choices of others, because only one such test has been conducted in a relatively asocial corvid. we investigated whether rela ...201627920957
detection of severe fever with thrombocytopenia syndrome virus from wild animals and ixodidae ticks in the republic of korea.severe fever with thrombocytopenia syndrome (sfts) is caused by sfts virus (sftsv), a novel bunyavirus reported to be endemic to central-northeastern china, southern japan, and the republic of korea (rok). to investigate sftsv infections, we collected serum samples and ticks from wild animals. using serum samples and ticks, sftsv-specific genes were amplified by one-step rt-pcr and nested pcr and sequenced. indirect immunofluorescence assay (ifa) was performed to analyze virus-specific antibody ...201627043361
crows rival monkeys in cognitive capacity.the present study compares the 'bandwidth of cognition' between crows and primates. working memory is the ability to maintain and manipulate information over short periods of time - a core component of cognition. the capacity of working memory is tightly limited, in humans correlated with individual intelligence and commonly used synonymously with cognitive capacity. crows have remarkable cognitive skills and while birds and mammals share neural principles of working memory, its capacity has not ...201728821812
great spotted cuckoo nestlings have no antipredatory effect on magpie or carrion crow host nests in southern spain.host defences against cuckoo parasitism and cuckoo trickeries to overcome them are a classic example of antagonistic coevolution. recently it has been reported that this relationship may turn to be mutualistic in the case of the carrion crow (corvus corone) and its brood parasite, the great spotted cuckoo (clamator glandarius), given that experimentally and naturally parasitized nests were depredated at a lower rate than non-parasitized nests. this result was interpreted as a consequence of the ...201728422953
socially driven consistent behavioural differences during development in common ravens and carrion crows.consistent individual differences in behaviour, or 'personality', are likely to be influenced by development, social context, and species ecology, though few comparative, longitudinal studies exist. here, we investigated the role of development and social context on personality variation in two identically reared, social corvids: common ravens and carrion crows. we repeatedly presented subjects with a variety of novel food and objects, while alone and in a primarily sibling subgroup, from fledgi ...201626848954
the genomic landscape underlying phenotypic integrity in the face of gene flow in crows.the importance, extent, and mode of interspecific gene flow for the evolution of species has long been debated. characterization of genomic differentiation in a classic example of hybridization between all-black carrion crows and gray-coated hooded crows identified genome-wide introgression extending far beyond the morphological hybrid zone. gene expression divergence was concentrated in pigmentation genes expressed in gray versus black feather follicles. only a small number of narrow genomic is ...201424948738
an extensive candidate gene approach to speciation: diversity, divergence and linkage disequilibrium in candidate pigmentation genes across the european crow hybrid zone.colouration patterns have an important role in adaptation and speciation. the european crow system, in which all-black carrion crows and grey-coated hooded crows meet in a narrow hybrid zone, is a prominent example. the marked phenotypic difference is maintained by assortative mating in the absence of neutral genetic divergence, suggesting the presence of few pigmentation genes of major effect. we made use of the rich phenotypic and genetic resources in mammals and identified a comprehensive pan ...201323881172
[genetic variation of carrion and hooded crows and their hybrids based on rapd-pcr data].rapd-pcr analysis of genetic variability of carrion crows, hooded crows and their phenotypic hybrids from the zones of overlap of their areals and hybridization of parental forms in siberia has been carried out. according to rapd variability the following parameters were estimated for both species and their hybrids: genetical distances (dn), polymorphism (p95), mean expected heterozygosity (h(e)), gene fixation coefficient (fst) and the portion of interpopulation differentiation (gst). it was sh ...200815131967
[numerousness judgement in hooded crows: generalization by the "more than" concept].four carrion crows were trained to choose the greater array from pairs of numerousness discriminanda in the range of 1-12. in the process of training all irrelevant attributes of the arrays (geometric form, size and color of elements, patterns of distribution) were varied. several control procedures were employed to make extraneous cues unlikely. in particular, in order to preclude the use of cumulative area or other magnitude cues the ratio of cumulative area of elements to their number was var ...20067645324
carrion crows (corvus corone) of southwest germany: important hosts for haemosporidian parasites.avian malaria parasites (plasmodium spp.) and other haemosporida (haemoproteus and leucocytozoon spp.) form a diverse group of vector-transmitted blood parasites that are abundant in many bird families. recent studies have suggested that corvids may be an important host for plasmodium spp. and leucocytozoon spp.201728899382
ecological role of vertebrate scavengers in urban ecosystems in the uk.recent research has demonstrated how scavenging, the act of consuming dead animals, plays a key role in ecosystem structure, functioning, and stability. a growing number of studies suggest that vertebrate scavengers also provide key ecosystem services, the benefits humans gain from the natural world, particularly in the removal of carcasses from the environment. an increasing proportion of the human population is now residing in cities and towns, many of which, despite being highly altered envir ...201628725378
serologic evidence of west nile virus and usutu virus infections in eurasian coots in the netherlands.west nile virus (wnv) and usutu virus (usuv) are arboviruses that are maintained in enzootic transmission cycles between mosquitoes and birds and are occasionally transmitted to mammals. as arboviruses are currently expanding their geographic range and emerging in often unpredictable locations, surveillance is considered an important element of preparedness. to determine whether sera collected from resident and migratory birds in the netherlands as part of avian influenza surveillance would also ...201728688117
key role in ecosystem functioning of scavengers reliant on a single common species.the importance of species richness in maintaining ecosystem function in the field remains unclear. recent studies however have suggested that in some systems functionality is maintained by a few abundant species. here we determine this relationship by quantifying the species responsible for a key ecosystem role, carcass removal by scavengers. we find that, unlike those within largely unaltered environments, the scavenger community within our highly altered system is dominated by a single species ...201627404915
abstract rule neurons in the endbrain support intelligent behaviour in corvid songbirds.despite the lack of a layered neocortex and fundamental differences in endbrain organization in birds compared with mammals, intelligent species evolved from both vertebrate classes. among birds, corvids show exceptional cognitive flexibility. here we explore the neuronal foundation of corvid cognition by recording single-unit activity from an association area known as the nidopallium caudolaterale (ncl) while carrion crows make flexible rule-guided decisions, a hallmark of executive control fun ...201324285080
did tool-use evolve with enhanced physical cognitive abilities?the use and manufacture of tools have been considered to be cognitively demanding and thus a possible driving factor in the evolution of intelligence. in this study, we tested the hypothesis that enhanced physical cognitive abilities evolved in conjunction with the use of tools, by comparing the performance of naturally tool-using and non-tool-using species in a suite of physical and general learning tasks. we predicted that the habitually tool-using species, new caledonian crows and galápagos w ...201324101628
you sound familiar: carrion crows can differentiate between the calls of known and unknown heterospecifics.in group-living animals, it is adaptive to recognize conspecifics on the basis of familiarity or group membership as it allows association with preferred social partners and avoidance of competitors. however, animals do not only associate with conspecifics but also with heterospecifics, for example in mixed-species flocks. consequently, between-species recognition, based either on familiarity or even individual recognition, is likely to be beneficial. the extent to which animals can distinguish ...201222538713
molecular scatology: how to improve prey dna detection success in avian faeces?the analysis of prey dna in faeces is a non-invasive approach to examine the diet of birds. however, it is poorly known how gut transition time, environmental factors and laboratory treatments such as storage conditions or dna extraction procedures affect the detection success of prey dna. here, we examined several of these factors using faeces from carrion crows fed with insect larvae. faeces produced between 30 min and 4 h post-feeding tested positive for insect dna, representing the gut trans ...201121676193
tool-making new caledonian crows have large associative brain areas.animals with a high rate of innovative and associative-based behavior usually have large brains. new caledonian (nc) crows stand out due to their tool manufacture, their generalized problem-solving abilities and an extremely high degree of encephalization. it is generally assumed that this increased brain size is due to the ability to process, associate and memorize diverse stimuli, thereby enhancing the propensity to invent new and complex behaviors in adaptive ways. however, this premise lacks ...201020215728
[control of birds in the agricultural area: the rook and carrion crow]. 19863522175
comparing the face inversion effect in crows and humans.humans show impaired recognition of faces that are presented upside down, a phenomenon termed face inversion effect, which is thought to reflect the special relevance of faces for humans. here, we investigated whether a phylogenetically distantly related avian species, the carrion crow, with similar socio-cognitive abilities to human and non-human primates, exhibits a face inversion effect. in a delayed matching-to-sample task, two crows had to differentiate profiles of crow faces as well as mat ...201728905251
evolution of cognitive and neural solutions enabling numerosity judgements: lessons from primates and corvids.brains that are capable of representing numerosity, the number of items in a set, have arisen repeatedly and independently in different animal taxa. this review compares the cognitive and physiological mechanisms found in a nonhuman primate, the rhesus macaque, and a corvid songbird, the carrion crow, in order to elucidate the evolutionary adaptations underlying numerical competence. monkeys and corvids are known for their advanced cognitive competence, despite them both having independently and ...201729292361
culicoides species composition and molecular identification of host blood meals at two zoos in the uk.culicoides biting midges are biological vectors of arboviruses including bluetongue virus (btv), schmallenberg virus (sbv) and african horse sickness virus (ahsv). zoos are home to a wide range of 'at risk' exotic and native species of animals. these animals have a high value both in monetary terms, conservation significance and breeding potential. to understand the risk these viruses pose to zoo animals, it is necessary to characterise the culicoides fauna at zoos and determine which potential ...202032178710
crows control working memory before and after stimulus encoding.the capacity of working memory is limited and this limit is comparable in crows and primates. to maximize this resource, humans use attention to select only relevant information for maintenance. interestingly, attention-cues are effective not only before but also after the presentation of to-be-remembered stimuli, highlighting control mechanisms beyond sensory selection. here we explore if crows are also capable of these forms of control over working memory. two crows (corvus corone) were traine ...202032094457
dominance relationships and coalitionary aggression against conspecifics in female carrion crows.cooperation is a prevailing feature of many animal systems. coalitionary aggression, where a group of individuals engages in coordinated behaviour to the detriment of conspecific targets, is a form of cooperation involving complex social interactions. to date, evidence has been dominated by studies in humans and other primates with a clear bias towards studies of male-male coalitions. we here characterize coalitionary aggression behaviour in a group of female carrion crows consisting of recruitm ...201931685854
a review of predation as a limiting factor for bird populations in mesopredator-rich landscapes: a case study of the uk.the impact of increasing vertebrate predator numbers on bird populations is widely debated among the general public, game managers and conservationists across europe. however, there are few systematic reviews of whether predation limits the population sizes of european bird species. views on the impacts of predation are particularly polarised in the uk, probably because the uk has a globally exceptional culture of intensive, high-yield gamebird management where predator removal is the norm. in a ...201829790246
selecting appropriate focal species for assessing the risk to birds from newly drilled pesticide-treated winter cereal fields in france.identifying focal bird species appropriate to the situation in which a plant protection product is used is important for refined risk assessment (efsa ). we analyzed the results of extensive field observations of newly drilled cereal fields in france in autumn over 2 seasons to determine real bird focal species. in 2011, birds were observed before and after drilling on wheat and barley fields drilled with imidacloprid-treated seeds (i.e., "treatment" fields) or seeds treated with compounds other ...201930515968
a comparative analysis of the dopaminergic innervation of the executive caudal nidopallium in pigeon, chicken, zebra finch, and carrion crow.despite the long, separate evolutionary history of birds and mammals, both lineages developed a rich behavioral repertoire of remarkably similar executive control generated by distinctly different brains. the seat for executive functioning in birds is the nidopallium caudolaterale (ncl) and the mammalian equivalent is known as the prefrontal cortex (pfc). both are densely innervated by dopaminergic fibers, and are an integration center of sensory input and motor output. whereas the variation of ...202032020608
antimicrobial resistant and extended-spectrum β-lactamase producing escherichia coli in common wild bird species in switzerland.a total of 294 fecal swabs from 294 wild birds in switzerland were cultivated for antimicrobial resistant (amr) escherichia coli. samples were also subcultivated to detect e. coli with extended-spectrum β-lactamases (esbl), carbapenemases, and plasmid-mediated aminoglycoside or colistin resistance, respectively. samples from 17 (5.8%) of the birds contained 19 amr e. coli, whereof 26.3% were multidrug resistant. five (1.7%) esbl-producing e. coli were detected. the isolates harbored blactx-m-1 ( ...201931006991
monitoring of heavy metal burden in wild birds at eastern/north-eastern part of hungary.concentrations of different heavy metals (as, cd, cr, cu, hg, pb, zn) were examined in the contour feathers of long-eared owl (asio otus), little owl (athene noctua), tawny owl (strix aluco), barn owl (tyto alba), eurasian sparrowhawk (accipiter nisus), rook (corvus frugilegus), hooded crow (corvus cornix), carrion crow (corvus corone), common buzzard (buteo buteo) and barn swallow (hirundo rustica). the samples were collected from the hortobágyi madárpark (bird hospital foundation) in hungary. ...201829249025
revisiting an old question: which predators eat eggs of ground-nesting birds in farmland landscapes?nest predation is a major cause of reproductive failure in birds, but predator identity often remains unknown. additionally, although corvids are considered major nest predators in farmland landscapes, whether breeders or floaters are involved remains contentious. in this study, we aimed to identify nest predators using artificial nests, and test whether territorial or non-breeders carrion crow (corvus corone) and eurasian magpie (pica pica) were most likely involved. we set up an experiment wit ...202032721676
carrion crows (corvus corone corone) fail the mirror mark test yet again.the mirror mark test is generally considered to be an indicator of an animal's ability to recognize itself in the mirror. for this test, an animal is confronted with a mirror and has a mark placed where it can see the mark only with the help of the mirror. when the animal extensively touches or interacts with the mark, compared with control conditions, the mirror mark test is passed. many nonhuman animal species have been tested, but few have succeeded. after magpies and indian house crows passe ...202032463251
extra-pair paternity as a strategy to reduce the costs of heterospecific reproduction? insights from the crow hybrid zone.within hybrid zones of socially monogamous species, the number of mating opportunities with a conspecific can be limited. as a consequence, individuals may mate with a heterospecific (social) partner despite possible fitness costs to their hybrid offspring. extra-pair copulations with a conspecific may thus arise as a possible post hoc strategy to reduce the costs of hybridization. we here assessed the rate of extra-pair paternity in the hybrid zone between all-black carrion crows (corvus (coron ...202032069366
crows (corvus corone ssp.) check contingency in a mirror yet fail the mirror-mark test.mirror reflections can elicit various behavioral responses ranging from social behavior, which suggests that an animal treats its own reflection as a conspecific, to mirror-guided self-directed behaviors, which appears to be an indication for mirror self-recognition (msr). msr is scarcely spread in the animal kingdom. until recently, only great apes, dolphins, and elephants had successfully passed this test. the range of convergence was, however, expanded by an avian species, the eurasian magpie ...202031589059
volitional control of vocalizations in corvid songbirds.songbirds are renowned for their acoustically elaborate songs. however, it is unclear whether songbirds can cognitively control their vocal output. here, we show that crows, songbirds of the corvid family, can be trained to exert control over their vocalizations. in a detection task, three male carrion crows rapidly learned to emit vocalizations in response to a visual cue with no inherent meaning (go trials) and to withhold vocalizations in response to another cue (catch trials). two of these c ...201931454343
neuronal correlates of spatial working memory in the endbrain of crows.birds are renowned for their excellent spatial cognition. corvid songbirds, in particular, rely on explicit representation of spatial cues in memory when caching food and retrieving caches for later consumption. however, the neuronal correlates of flexible spatial memory abilities are largely unknown in birds. we therefore trained carrion crows (corvus corone) on a spatial delayed-response task in which they had to maintain the variable location of a visual item for a few seconds in working memo ...201931378607
waste disposal sites as all-you-can eat buffets for carrion crows (corvus corone).in cities and densely populated areas, several corvid species are considered nuisance animals. in austria, particularly carrion (corvus corone) and hooded crows (c. cornix) are regarded as pests by the general public that frequently cause damage to crops, feed on human waste, and thus spread trash. we conducted a detailed one-year field survey to estimate the abundance of carrion crows in relation to potential anthropogenic food sources and reference sites in the austrian rhine valley. our resul ...201931060242
epistatic mutations under divergent selection govern phenotypic variation in the crow hybrid zone.the evolution of genetic barriers opposing interspecific gene flow is key to the origin of new species. drawing from information on over 400 admixed genomes sourced from replicate transects across the european hybrid zone between all-black carrion crows and grey-coated hooded crows, we decipher the interplay between phenotypic divergence and selection at the molecular level. over 68% of plumage variation was explained by epistasis between the gene ndp and a ~2.8-megabase region on chromosome 18 ...201930911146
counting crows: population structure and group size variation in an urban population of crows.social complexity arises from the formation of social relationships like social bonds and dominance hierarchies. in turn, these aspects may be affected by the degree of fission-fusion dynamics, i.e., changes in group size and composition over time. whilst fission-fusion dynamics has been studied in mammals, birds have received comparably little attention, despite some species having equally complex social lives. here, we investigated the influence of environmental factors on aspects of fission-f ...202030846892
allometry and integration do not strongly constrain beak shape evolution in large-billed (corvus macrorhynchos) and carrion crows (corvus corone).a recent geometric morphometric study on certain landbird lineages revealed that a major part of the variation in beak shape is accounted for by skull size and cranial shape. the study interpreted this result as evidence for the presence of strong evolutionary constraints that severely prevented beak shape from evolving substantially away from predictions of allometry and morphological integration. however, there is another overlooked but similarly plausible explanation for this result: the reas ...201830397447
isolation of brachyspira hyodysenteriae from a crow (corvus corone) in close proximity to commercial pigs.the aim of this study was to determine whether crows (corvus corone) can harbour brachyspira hyodysenteriae, the cause of swine dysentery, and whether the organism carried by crows is related to strains infecting pigs. b. hyodysenteriae was isolated from one crow in close proximity to two pig farms in switzerland. this isolate, along with five isolates of b. hyodysenteriae from one of the farms, belonged to sequence type (st) 66 using multilocus sequence typing. this finding suggests that crows ...201829871743
neurons in the crow nidopallium caudolaterale encode varying durations of visual working memory periods.adaptive sequential behaviors rely on the bridging and integration of temporally separate information for the realization of prospective goals. corvids' remarkable behavioral flexibility is thought to depend on the workings of the nidopallium caudolaterale (ncl), a high-level avian associative forebrain area. we trained carrion crows to remember visual items for three alternating delay durations in a delayed match-to-sample task and recorded single-unit activity from the ncl. sample-selective de ...201829128976
formal comment to soler et al.: great spotted cuckoo nestlings have no antipredatory effect on magpie or carrion crow host nests in southern spain. 201728922382
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