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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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
growth and sex ratio of nestlings in two species of crows: how important is hatching asynchrony?in experimental studies of avian hatching paterns offspring sex has been neglected. this may be a problem if nestling growth and mortality is sex biased, and if this bias is influenced by hatching spread. in a field study of two crow species, the magpie pica pica and the hooded crow corvus corone cornix, we manipulated hatching spread. both species have asynchronous hatching, and adult males are larger than females by 12-14%. the sex ratios obtained from the different experimental groups on day ...199228312269
occurrence and relevance of mycoplasma sturni in free-ranging corvids in germany.several mycoplasma spp. are well-known pathogens in poultry. in birds of prey, white storks ( ciconia ciconia ), and some waterfowl (anatidae, pelecanidae) species, mycoplasmas occur commonly and seem to be apathogenic or commensal and most likely belong to the physiologic microbial flora of the respiratory tract. in other bird species, such as common nightingales ( luscinia megarhynchos ) and tits (paridae), mycoplasma spp. are absent in healthy birds. in corvids, the prevalence and role of myc ...201728099075
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
behavioural type affects space use in a wild population of crows (corvus corone).while personality-dependent dispersal is well studied, local space use has received surprisingly little attention in this context, despite the multiple consequences on survival and fitness. regarding the coping style of individuals, recent studies on personality-dependent space use within a habitat indicate that 'proactive' individuals are wider ranging than 'reactive' ones. however, such studies are still scarce and cover limited taxonomic diversity, and thus, more research is needed to explore ...201627840464
responses of urban crows to con- and hetero-specific alarm calls in predator and non-predator zoo enclosures.urban animals and birds in particular are able to cope with diverse novel threats in a city environment such as avoiding novel, unfamiliar predators. predator avoidance often includes alarm signals that can be used also by hetero-specifics, which is mainly the case in mixed-species flocks. it can also occur when species do not form flocks but co-occur together. in this study we tested whether urban crows use alarm calls of conspecifics and hetero-specifics (jackdaws, corvus monedula) differently ...201727796660
encoding of global visual motion in the nidopallium caudolaterale of behaving crows.songbirds possess acute vision. how higher brain centres represent basic and parameterised visual stimuli to process sensory signals according to their behavioural importance has not been studied in a systematic way. we therefore examined how carrion crows (corvus corone) and their nidopallial visual neurons process global visual motion information in dynamic random-dot displays during a delayed match-to-sample (dms) task. the behavioural data show that moderately fast motion speeds (16° of visu ...201727718536
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
explorative innovators and flexible use of social information in common ravens (corvus corax) and carrion crows (corvus corone).innovation and social information use are influenced by individual characteristics, and are important for the creation and transmission of novel behavioral patterns. here, we investigated which individual factors predict innovation rates and social transmission of information in a comparative study with identically reared common ravens (corvus corax) and carrion crows (corvus corone corone; corvus corone cornix). in the innovation experiment (1), we presented the birds with a novel problem-solvi ...201627359074
blood parasites in hooded crows (corvus corone cornix) in northwest italy.haemoparasites and their effects on hooded crows (corvus corone cornix) are poorly studied. the aims are to evaluate the prevalence of haemoproteus spp./plasmodium spp. or leucocytozoon spp., to correlate this with gross and histopathological findings, and to investigate the association among infection and geographical origin, age, gender, parasite distribution and prevalence among organs. hooded crows (n = 47) were collected within a regional culling programme from 3 districts in the province o ...201627188825
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
thermal emissivity of avian eggshells.the hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. directional thermal emissivity has been estimated from directional-hemispherical reflectance spectra. due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. most notably, small waders of the genu ...201627033033
numerosity representations in crows obey the weber-fechner law.the ability to estimate number is widespread throughout the animal kingdom. based on the relative close phylogenetic relationship (and thus equivalent brain structures), non-verbal numerical representations in human and non-human primates show almost identical behavioural signatures that obey the weber-fechner law. however, whether numerosity discriminations of vertebrates with a very different endbrain organization show the same behavioural signatures remains unknown. therefore, we tested the n ...201627009227
an epizootic of emerging novel avian pox in carrion crows (corvus corone) and large-billed crows (corvus macrorhynchos) in japan.in 2006-10, an epizootic of emerging avian pox occurred in carrion crows ( corvus corone ) and large-billed crows ( corvus macrorhynchos ), leading to mortality of juvenile crows in hokkaido, the northernmost island of japan. we diagnosed 27 crows with proliferative skin lesions (19 carcasses and eight biopsied cases [one in zoo captivity]) as avian pox clinically, histopathologically by detection of avipoxvirus-specific 4b core protein (p4b) gene, and epidemiologically. the fatal cases demonstr ...201626967129
density-dependent regulation of fecundity in syngamus trachea infrapopulations in semi-naturally occurring ring-necked pheasants (phasianus colchicus) and wild carrion crows (corvus corone).previous work has highlighted increased opportunities for the transmission of syngamus trachea within pheasant release pens, due in part to high levels of environmental contamination around communal areas. despite this, the distribution of adult worms within their definitive hosts is not significantly different from predicted distributions under taylor's power law. therefore, density-dependent processes are probably acting to regulate s. trachea population dynamics. patterns of nematode fecundit ...201626932519
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
prevalence of mycoplasma gallisepticum and mycoplasma synoviae in commercial poultry, racing pigeons and wild birds in belgium.mycoplasma gallisepticum is the most important pathogenic avian mycoplasma species and causes chronic respiratory disease in poultry. in addition, the prevalence of mycoplasma synoviae is of increasing concern in several eu member states. we investigated the prevalence of m. gallisepticum in commercial poultry (5220 layers, 1224 broilers and 1020 meat turkeys), 56 racing pigeons and 890 wild birds (order anseriformes, galliformes, pelecaniformes, accipitriformes, gruiformes, charadriiformes, col ...201626814376
assessing animal welfare impacts in the management of european rabbits (oryctolagus cuniculus), european moles (talpa europaea) and carrion crows (corvus corone).human-wildlife conflict is a global issue. attempts to manage this conflict impact upon wild animal welfare, an issue receiving little attention until relatively recently. where human activities harm animal welfare these effects should be minimised where possible. however, little is known about the welfare impacts of different wildlife management interventions, and opinions on impacts vary widely. welfare impacts therefore need to be assessed objectively. our objectives were to: 1) establish whe ...201626726808
associative learning rapidly establishes neuronal representations of upcoming behavioral choices in crows.the ability to form associations between behaviorally relevant sensory stimuli is fundamental for goal-directed behaviors. we investigated neuronal activity in the telencephalic area nidopallium caudolaterale (ncl) while two crows (corvus corone) performed a delayed association task. whereas some paired associates were familiar to the crows, novel associations had to be learned and mapped to the same target stimuli within a single session. we found neurons that prospectively encoded the chosen t ...201526598669
transcriptomics of colour patterning and coloration shifts in crows.animal coloration is one of the most conspicuous phenotypic traits in natural populations and has important implications for adaptation and speciation. changes in coloration can occur over surprisingly short evolutionary timescales, while recurrence of similar colour patterns across large phylogenetic distances is also common. even though the genetic basis of pigment production is well understood, little is known about the mechanisms regulating colour patterning. in this study, we shed light on ...201526302355
next-generation sequencing shows west nile virus quasispecies diversification after a single passage in a carrion crow (corvus corone) in vivo infection model.west nile virus (wnv) occurs as a population of genetic variants (quasispecies) infecting a single animal. previous low-resolution viral genetic diversity estimates in sampled wild birds and mosquitoes, and in multiple-passage adaptation studies in vivo or in cell culture, suggest that wnv genetic diversification is mostly limited to the mosquito vector. this study investigated genetic diversification of wnv in avian hosts during a single passage using next-generation sequencing. wild-captured c ...201526297666
cross-modal associative mnemonic signals in crow endbrain neurons.the ability to associate stimuli across time and sensory modalities endows animals and humans with many of the complex, learned behaviors. for successful performance, associations need to be retrieved from long-term memory and maintained active in working memory. we investigated how this is accomplished in the avian brain. we trained carrion crows (corvus corone) to perform a bimodal delayed paired associate task in which the crows had to match auditory stimuli to delayed visual items. single-un ...201526255848
morphological and molecular genetic characterization of three capillaria spp. (capillaria anatis, capillaria pudendotecta, and capillaria madseni) and baruscapillaria obsignata (nematoda: trichuridae: capillariinae) in avians.morphological and genetic analyses were performed on four avian species of the subfamily capillariinae (nematoda: trichuridae), i.e., capillaria anatis from chickens (gallus gallus domesticus) in japan and the philippines, baruscapillaria obsignata from chickens and captive swans (cygnus olor and cygnus atratus) in japan, capillaria pudendotecta from captive swans in japan, and capillaria madseni from carrion and jungle crows (corvus corone and corvus macrorhynchos) in japan. although morphometr ...201526204803
susceptibility of carrion crows to experimental infection with lineage 1 and 2 west nile viruses.west nile virus (wnv) outbreaks in north america have been characterized by substantial die-offs of american crows (corvus brachyrhynchos). in contrast, a low incidence of bird deaths has been observed during wnv epidemic activity in europe. to examine the susceptibility of the western european counterpart of american crows, we inoculated carrion crows (corvus corone) with wnv strains isolated in greece (gr-10), italy (fin and ita09), and hungary (578/10) and with the highly virulent north ameri ...026197093
differences in exploration behaviour in common ravens and carrion crows during development and across social context.exploration is particularly important for young animals, as it enables them to learn to exploit their surroundings. it is likely to be affected by species ecology and social context, though there are few comparative, longitudinal studies that control for effects of early experience. here, we investigated group level exploration behaviour in two closely related and identically reared, generalist corvid species: common ravens (corvus corax) and carrion crows (c. corone, c. cornix), during developm ...201726097282
carrion crows learn to discriminate between calls of reliable and unreliable conspecifics.partner choice on the basis of an individual's reliability is expected to stabilize social interactions. in this experiment, we tested whether carrion crows (corvus corone corone) learn to differentiate between calls of reliable or unreliable individuals. crows were kept in an aviary that comprised four visually but not acoustically isolated compartments, separated by a central room. in an association phase, a dead crow placed in the central compartment was visible only to one of the four crow g ...201526067282
tolerance and social facilitation in the foraging behaviour of free-ranging crows (corvus corone corone; c. c. cornix).social foraging provides animals with opportunities to gain knowledge about available food. studies indicate that animals are influenced by social context during exploration and are able to learn socially. carrion and hooded crows, which are opportunistic generalists with flexible social systems, have so far received little focus in this area. we combined observational and experimental approaches to investigate social interactions during foraging and social influences on crow behaviour within a ...201425937686
waiting for better, not for more: corvids respond to quality in two delay maintenance tasks.self-control, that is, overcoming impulsivity towards immediate gratification in favour of a greater but delayed reward, is seen as a valuable skill when making future-oriented decisions. experimental studies in nonhuman primates revealed that individuals of some species are willing to tolerate delays of up to several minutes in order to gain food of a higher quantity or quality. recently, birds (carrion crows, corvus corone, common ravens, corvus corax, goffin cockatoos, cacatua goffiniana) per ...201425892738
patterns of evolution of mhc class ii genes of crows (corvus) suggest trans-species polymorphism.a distinguishing characteristic of genes that code for the major histocompatibility complex (mhc) is that alleles often share more similarity between, rather than within species. there are two likely mechanisms that can explain this pattern: convergent evolution and trans-species polymorphism (tsp), in which ancient allelic lineages are maintained by balancing selection and retained by descendant species. distinguishing between these two mechanisms has major implications in how we view adaptatio ...201525802816
behavioural responses to olfactory cues in carrion crows.until recently, the use of olfactory signals in birds has been largely ignored, despite the fact that birds do possess a fully functioning olfactory system and have been shown to use odours in social and foraging tasks, predator detection and orientation. the present study investigates whether carrion crows (corvus corone corone), a bird species living in complex social societies, respond behaviourally to olfactory cues of conspecifics. during our experiment, carrion crows were observed less oft ...201525447513
morphologic and molecular study of hemoparasites in wild corvids and evidence of sequence identity with plasmodium dna detected in captive black-footed penguins (spheniscus demersus).a morphologic and molecular epidemiologic investigation was conducted on a captive african black-footed penguin (spheniscus demersus) colony with a history of plasmodium infections at la palmyre zoo (france). each penguin received 12.5 mg of pyrimethamine twice a week as a prophylaxis every year from april to november. although plasmodium parasites were not detected in blood smears and tissues collected from the penguins, various blood parasites were recorded in blood smears from wild eurasian m ...201425314825
the long and the short of it: rule-based relative length discrimination in carrion crows, corvus corone.birds and other nonhuman animals can choose the larger of two discrete or continuous quantities. however, whether birds possess the conceptual grasp and cognitive control to flexibly switch between relative more-or-less-than judgments remains elusive. we therefore tested carrion crows in a rule-based line-length discrimination task to flexibly select lines presented on a touchscreen according to their relative length. in the first experiment, the crows needed to discriminate a shorter from a lon ...201425151937
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
neuronal correlates of visual working memory in the corvid endbrain.the concept of working memory is key to cognitive functioning. working memory encompasses the capacity to retain immediately past information, to process this information, and to use it to guide goal-directed behavior. corvid songbirds are renowned for their high-level cognitive capabilities, but where and how visual information is temporarily retained by neurons in the avian brain in a behaviorally relevant way remains poorly understood. we trained four carrion crows (corvus corone) on versions ...201424899702
test of magnetic sensitivity in seven species of european birds using a cardiac nociceptive conditioning procedure.an attempt was made to show magnetic sensitivity in seven species of european birds captured during their migration. the test was done on the following species: streptopelia turtur (n=8), streptopelia decaocto (n=2), corvus monedula (n=6); one individual of the following: corvus corone c., turdus philomelos, turdus viscivorus, anas penelope. most of the individuals were first subjected to conditioning to a light stimulus. they were then subjected to differential nociceptive conditioning to 100 p ...197724896432
avian blood induced intranuclear translocation of stat3 via the chicken leptin receptor.leptin is a multi-functional adipokine in vertebrates. the leptin gene and protein are found in many vertebrates; however, the existence of leptin in birds remains controversial. here we detected leptin-like activity in avian blood using chicken leptin receptor (chlepr) and green fluorescent protein (gfp)-fused chicken signal transducer and activator of transcription (chstat3) co-expressed in cho-k1 cells (cho-chlepr/stat3). we validated that rat serum specifically induces intranuclear migration ...201424858374
chicks of the great spotted cuckoo may turn brood parasitism into mutualism by producing a foul-smelling secretion that repels predators.the great spotted cuckoo (clamator glandarius) is an important brood parasite of carrion crows (corvus corone corone) in northern spain. we recently found that, unlike what is commonly known for cuckoo-host interactions, the great spotted cuckoo has no negative impact on average crow fitness in this region. the explanation for this surprising effect is a repulsive secretion that the cuckoo chicks produce when they are harassed and that may protect the brood against predation. here, we provide de ...201424760177
from parasitism to mutualism: unexpected interactions between a cuckoo and its host.avian brood parasites lay eggs in the nests of other birds, which raise the unrelated chicks and typically suffer partial or complete loss of their own brood. however, carrion crows corvus corone corone can benefit from parasitism by the great spotted cuckoo clamator glandarius. parasitized nests have lower rates of predation-induced failure due to production of a repellent secretion by cuckoo chicks, but among nests that are successful, those with cuckoo chicks fledge fewer crows. the outcome o ...201424653032
an experimental study of vertebrate scavenging behavior in a northwest european woodland context.vertebrate scavengers can modify surface deposited human remains which can hinder forensic investigations. the effects of such scavenging vary between species and regions. published research into the effects of the scavenging of human remains is dominated by work from north america with few studies covering northwestern europe. forensic scientists, investigators, and police search officers in northwestern europe are often left questioning on a basic level as to which scavengers are active and ho ...201424611615
synanthropic birds and parasites.this paper describes the parasitologic findings for 60 synanthropic bird carcasses recovered in the campania region of southern italy. birds consisted of 20 yellow-legged gulls (larus michahellis), 15 rock pigeons (columba livia), 15 common kestrels (falco tinnunculus), and 10 carrion crows (corvus corone). each carcass was examined to detect the presence of ectoparasites and then necropsied to detect helminths. ectoparasites occurred in 100% of the birds examined. in particular, chewing lice we ...201324597118
outbreak of type c botulism in birds and mammals in the emilia romagna region, northern italy.over a 7-day period beginning 8 august 2011, a large number of wild birds of several species were found dead or with neurologic clinical signs along the shore of crostolo stream, in the emilia romagna region, italy. twenty-eight mallards (anas platyrhynchos), two hooded crows (corvus corone cornix), and three coypus (myocastor coypus) were found moribund on the crostolo stream bank, collected, and sent to istituto zooprofilattico sperimentale della lombardia e dell'emilia romagna, reggio emilia ...201324502738
familiarity with the experimenter influences the performance of common ravens (corvus corax) and carrion crows (corvus corone corone) in cognitive tasks.when humans and animals interact with one another over an extended time span they familiarise and may develop a relationship, which can exert an influence on both partners. for example, the behaviour of an animal in experiments may be affected by its relationship to the human experimenter. however, few studies have systematically examined the impact of human-animal relationships on experimental results. in the present study we investigated if familiarity with a human experimenter influences the ...201424333226
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
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
experimental infection of carrion crows (corvus corone) with two european west nile virus (wnv) strains.west nile virus (wnv) has become a wide-spread arbovirus in europe and the mediterranean basin countries. this emerging zoonotic disease disseminated 13 years ago in north america where its impact on animal and public health has been considerable. although american corvids have been the most reliable avian sentinels for wn surveillance in the united states, there is so far no data available about the susceptibility of their western european counterparts to wnv. clinical follow-up and serum, oral ...201323434187
west nile virus lineage 2 in sardinian wild birds in 2012: a further threat to public health.west nile virus (wnv) strains belonging to lineage 2 were detected and isolated from the tissues of a goshawk and two carrion crows in sardinia in august 2012. according to ns3 sequence analysis, the sardinian isolates shared a high level of similarity with those of italian lineage 2 strains which circulated in 2011 and with the homologous sequence of the 2004 hungarian isolate. following the human fatality reported in 2011 in olbia, this study is the first to report the spread and enzootic circ ...201323343580
comparative phylogeography of two crow species: jungle crow corvus macrorhynchos and carrion crow corvus corone.the jungle crow corvus macrorhynchos wagler, 1827, and the carrion crow corvus corone l., 1758, are two closely related species with similar ecological requirements that occupy wide distribution ranges in the palearctic. we studied patterns of their genetic variation by using sequences of the mitochondrial cytochrome b gene. corvus macrorhynchos demonstrates a low level of variation and differentiation throughout its range, except for a highly diverged population of cheju island (korea). the hap ...201222873805
the influence of local enhancement on choice performances in african grey parrots (psittacus erithacus) and jackdaws (corvus monedula).being attentive to the behavior of others may be advantageous to gain important information, for example, on the location of food. often, this is achieved through simple local enhancement. however, this is not always beneficial, as it may override cognitive abilities, with negative consequences. grey parrots (psittacus erithacus) and ravens have already succeeded in exclusion tasks, but carrion crows do so only when controlling for local enhancement, and jackdaws (corvus monedula) fail entirely. ...201222866773
apes (gorilla gorilla, pan paniscus, p. troglodytes, pongo abelii) versus corvids (corvus corax, c. corone) in a support task: the effect of pattern and functionality.apes (gorilla gorilla, pan paniscus, p. troglodytes, pong abelii) and corvids (corvus corax, c. corone) are among the most proficient and flexible tool users in the animal kingdom. although it has been proposed that this is the result of convergent evolution, little is known about whether this is limited to behavior or also includes the underlying cognitive mechanisms. we compared several species of apes (bonobos, chimpanzees, gorillas, and orangutans) and corvids (carrion crows and common raven ...201222545765
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
carrion crows cannot overcome impulsive choice in a quantitative exchange task.the ability to control an immediate impulse in return for a more desirable - though delayed - outcome has long been thought to be a uniquely human feature. however, studies on non-human primates revealed that some species are capable of enduring delays in order to get food of higher quality or quantity. recently two corvid species, common raven (corvus corax) and carrion crow (corvus corone corone), exchanged food for a higher quality reward though seemed less capable of enduring delays when exc ...201222529833
[morphological studies in different avian species on artefacts induced by euthanasia with t 61 " or pentobarbital (narcoren)].in mammals (e. g. macaques, dogs, cats, rats, sheep) as well as in men (suicides) euthanasia performed by intravenous injection of t 61 leads to serious lesions in lung, kidney or/and liver (endothelial damage, hyperemia, oedema, necrosis). this is caused by the solvent dimethylformamide (dmf). in this study, in contrast, in different species of birds (e. g. blackbird, carrion crow, kestrel, common buzzard, homer pigeon, common wood pigeon, mallard duck) and various modes of applications and dos ...201322372321
corticosterone levels in host and parasite nestlings: is brood parasitism a hormonal stressor?parasite chicks from non-evictor species usually try to monopolize host parental care, thereby increasing considerably the level of food competition in the nest. here, we propose that brood parasitism is an important stressor for host and parasite nestlings and explore this hypothesis in the non-evictor great spotted cuckoo (clamator glandarius) and its main hosts, the same-sized black-billed magpie (pica pica) and the larger carrion crow (corvus corone). we experimentally created 3-nestling bro ...201222366505
gastrointestinal helminths of magpies (pica pica), rooks (corvus frugilegus) and carrion crows (corvus corone) in mazandaran province, north of iran.corvidae is a cosmopolitan family of oscine birds including crows, rooks, magpies, jays, chough, and ravens. these birds are migratory species, especially in the shortage of foods, so they can act like vectors for a wide range of microorganisms. they live generally in temperate climates and in a very close contact with human residential areas as well as poultry farms. there is no available information in the literature concerning the parasitic infections of these three species of corvidae in maz ...201122347286
corvids can decide if a future exchange is worth waiting for.evidence for time-dependent calculations about future rewards is scarce in non-human animals. in non-human primates, only great apes are comparable with humans. still, some species wait for several minutes to obtain a better reward in delayed exchange tasks. corvids have been shown to match with non-human primates in some time-related tasks. here, we investigate a delay of gratification in two corvid species, the carrion crow (corvus corone) and the common raven (corvus corax), in an exchange ta ...201121920957
is caching the key to exclusion in corvids? the case of carrion crows (corvus corone corone).recently, two corvid species, food-caching ravens and non-caching jackdaws, have been tested in an exclusion performance (ep) task. while the ravens chose by exclusion, the jackdaws did not. thus, foraging behaviour may affect ep abilities. to investigate this possibility, another food-caching corvid species, the carrion crow (corvus corone corone), was tested in the same exclusion task. we hid food under one of two cups and subsequently lifted either both cups, or the baited or the un-baited cu ...201121751005
investigations into an outbreak of corvid respiratory disease associated with pasteurella multocida.the possible cause of disease and mortality in corvids on an outdoor pig unit in the north of england between august 2007 and march 2008 was investigated. nine carrion crows (corvus corone corone) and nine rooks (corvus frugilegus), comprising five live-caught birds with clinical signs of respiratory disease, one live-caught bird without respiratory disease, and 12 birds submitted dead were examined. clinical signs, gross and histopathological examination, microbiology and toxicology indicated t ...201121711193
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
helpers at the nest compensate for reduced maternal investment in egg size in carrion crows.life history theory predicts that mothers should trade off current and future reproductive attempts to maximize lifetime fitness. when breeding conditions are favourable, mothers may either increase investment in the eggs to improve the quality of the offspring or save resources for future reproduction as the good raising environment is likely to compensate for a 'bad start'. in cooperatively breeding birds, the presence of helpers improves breeding conditions so that mothers may vary the number ...201121605220
identification of 20 polymorphic microsatellite loci in european crow (corvus corone) from existing passerine loci.the european crow (corvus corone) occurs in two subspecies (or species) with distinct plumage coloration: the black carrion crow (c. c. corone) and the grey and black hooded crow (c. c. cornix). we tested 42 passerine microsatellite loci for amplification in the european crow and identified 20 loci that were both polymorphic and easy to score. in 50 individuals sampled in the danish part of the species' pan-european hybrid zone, the number of alleles ranged between two and 21. one locus deviated ...200821585909
general lack of global dosage compensation in zz/zw systems? broadening the perspective with rna-seq.species with heteromorphic sex chromosomes face the challenge of large-scale imbalance in gene dose. microarray-based studies in several independent male heterogametic xx/xy systems suggest that dosage compensation mechanisms are in place to mitigate the detrimental effects of gene dose differences. however, recent genomic research on female heterogametic zz/zw systems has generated surprising results. in two bird species and one lepidopteran no evidence for a global dosage compensating mechanis ...201121284834
redescription of sphaerirostris picae (acanthocephala: centrorhynchidae) from magpie, pica pica, in northern iran, with special reference to unusual receptacle structures and notes on histopathology.adults of sphaerirostris picae (rudolphi, 1819) golvan, 1956 are described from european magpie, pica pica linnaeus (corvidae), collected in 2008 from wooded areas near the northern iranian town of tonekabon by the southern shores of the caspian sea. other specimens also were collected from corvus cornix linnaeus, corvus corone linnaeus, and corvus frugilegus linnaeus (corvidae) in the same location, as well as from some of these hosts in other locations. our specimens had 31-38 proboscis hook r ...201020557203
lazy group members are substitute helpers in carrion crows.in many cooperatively breeding societies, helping effort varies greatly among group members, raising the question of why dominant individuals tolerate lazy subordinates. in groups of carrion crows corvus corone corone, helpers at the nest increase breeders' reproductive success, but chick provisioning is unevenly distributed among non-breeders, with a gradient that ranges from individuals that work as much as the breeders to others that completely refrain from visiting the nest. here we show tha ...201020519217
epidemiology of west nile in europe and in the mediterranean basin.in the last 30 years several cases of west nile (wn) virus infection were reported in horses and humans in europe and in the mediterranean basin. most of them were determined by strains of the lineage 1 included in the european mediterranean/kenyan cluster. strains of this cluster are characterised by a moderate pathogenicity for horses and humans and limited or no pathogenicity for birds. in recent years, however, wn cases determined by strains grouped in the israeli/american cluster of lineage ...201020517490
nucleotide divergence vs. gene expression differentiation: comparative transcriptome sequencing in natural isolates from the carrion crow and its hybrid zone with the hooded crow.recent advances in sequencing technology promise to provide new strategies for studying population differentiation and speciation phenomena in their earliest phases. we focus here on the black carrion crow (corvus [corone] corone), which forms a zone of hybridization and overlap with the grey coated hooded crow (corvus [corone] cornix). however, although these semispecies are taxonomically distinct, previous analyses based on several types of genetic markers did not reveal significant molecular ...201020331778
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
west nile virus transmission in 2008 in north-eastern italy.after 10 years, west nile virus (wnv) re-emerged in italy in august 2008. as on 31 december 2008, the infection affected eight provinces in three regions (emilia romagna, veneto, lombardy), where a total of 794 cases of wnv infection in 251 equine stables were detected on the basis of the clinical signs and as a result of a serological screening in horses living in the area. only 4.0% (32/794) of the serologically positive animals showed clinical signs, and the 32 clinical cases were reported in ...201020042066
frequent development of inflammatory lesions and lymphoid foci in the kidneys of japanese wild crows (corvus macrorhynchos and corvus corone) as a result of the entry of causal agents via the renal portal blood.although the increase in the number of wild crows is causing social problems in urban areas, crows play an increasingly important role in monitoring serious infectious diseases, such as highly pathogenic avian influenza and west nile fever. to gain a better understanding of normal conditions and common disorders in crows, we conducted a retrospective study of wild crows captured in central japan in the 1990s and examined the necropsy findings from 166 jungle crows (corvus macrorhynchos) and 74 c ...201019996559
[animal reservoirs of human virulent microsporidian species].the main objective of the present study was to determined the occurrence of encephalitozoon intestinalis, e. hellem, e. cuniculi, and enterocytozoon bieneusi in poland in animal faecal using the fish (fluorescent in situ hybridization) and multiplex fish techniques. additional objectives included: (1) identification of animal hosts of microsporidia that are infectious to humans amongst free-ranging, captive, livestock and domestic animals; (2) a molecular analysis of randomly selected parasite i ...200919579789
an analysis of population genetic differentiation and genotype-phenotype association across the hybrid zone of carrion and hooded crows using microsatellites and mc1r.the all black carrion crow (corvus corone corone) and the grey and black hooded crow (corvus corone cornix) meet in a narrow hybrid zone across europe. to evaluate the degree of genetic differentiation over the hybrid zone, we genotyped crows from the centre and edges of the zone, and from allopatric populations in northern (scotland-denmark-sweden) and southern europe (western-central northern italy), at 18 microsatellites and at a plumage candidate gene, the mc1r gene. allopatric and edge popu ...200919076276
intestinal spirochetes isolated from wild-living jackdaws, hooded crows and rooks (genus corvus): provisionally designated "brachyspira corvi" sp. nov.intestinal spirochetes of genus brachyspira are commonly isolated from mammalian and avian hosts, and several species have been reported to cause enteric disease in pigs and birds. except for a previous publication on three isolates from corvid birds (order passeriformes, family corvidae, genus corvus), of which two are further studied in this paper, no other reports exist on brachyspira spp. of passerine birds. in this study, cloacal and intestinal swabs of small and large intestines were colle ...200818952187
avian hind-limb digit length ratios measured from radiographs are sexually dimorphic.sexual dimorphism in digit length ratios is well established in humans, and has been reported in other vertebrate species as well, including birds. the sign of sexual dimorphism in digit ratios may, however, vary both within and between vertebrate classes. it has been hypothesized that sex differences in digit ratios arise via differential prenatal exposure of the two sexes to steroids, which may affect the expression of the hox genes controlling the osteometric development of digits and appendi ...200818691377
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