The diet of coastal breeding hooded crows corvus corone comix

Three methods of analysis were used to determine the diet of territorial hooded crows at Lough Hyne Marine Reserve, Co Cork, Ireland The regular collection of prey Items from these sites at Lough Hyne was integrated with pellet and stomach analysis to determine diet Intertidal organisms occurred in over 80% of pellets and 43% of stomachs and occupied over 77% of the total wet weight of foods identified in pellets All prey items recovered from drop sites originated from the intertidal habitat, involved either large-sized species or larger individuals of smaller-sized species, and were only dropped during October to February Twenty-five intertidal species were identified but only a few of these species contributed to the bulk of the diet Hooded crows were shown to consume a wide range of intertidal species throughout the year, though the species composition in the diet was seasonally influenced Depletion and weight loss of intertidal molluscs through the winter was shown to have a minimal effect on selection suggesting that prey switching was driven by the birds nutritional requirements     

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 shown that the rate of genetic variability in carrion crows and hooded crows is less than in the hybrids. It turned out that the hybrids were genetically closer to each other (DN = 0.295) than to both parental species (DN = 0.441 and 0.397 with C. corone and C. cornix, correspondingly). The studied individuals of C. cornix show the minimal level of heterozygosity and polymorphism (H(e) = 0.12 and P95 = = 27.8%) in comparison with C. corone and the crows of hybrid zone (H(e) = 0.18 and 0.20; P95 = 42.6% and 50.4%, correspondingly). Right's indexes of inbreeding (Fst = 0.285) and population spliting (Gst = 0.352) indicate low genetic variability in all the analysed birds. Nevertheless UPGMA and NJ dendrogrammes differentiate the individuals from the areals of carrion crows, hooded crows and from hybrid zone to different clusters. Our data correlate with molecular-genetic investigations of Corvidae carried out with other methods, and do not contradict the conception of carrion crows and hooded crows as semispecies in the context of the conception of overspecies.     

Ignorant hooded crows follow knowledgeable roost-mates to food: support for the information centre hypothesis

Communal roosting in birds may function to enhance foraging efficiency as explained by the information centre hypothesis, which predicts that successful foragers return from the roost to the rewarding food patch and that birds ignorant of this food follow knowledgeable roost-mates. We tested these predictions by exposing 34 radio-tagged, free-ranging, flock-living hooded crows (Corvus corone cornix) to a novel experimental set-up mimicking a superfluous food patch with maximum temporal and spatial unpredictability Each replicate lasted two days and was located on a new site. Data were collected during ten replicates over three years. First, a crow was more likely to visit the experimental food patch on the second day when it had been there on the first day. Second, when a crow had not been at this food patch on the first day, it was more likely to visit it on the second day if it had roosted together with a crow that had been there on the first day, but only if this knowledgeable roost-mate returned to the food patch on the second day. Our results support the information centre hypothesis and suggest that communal roosting might function to enhance foraging efficiency in hooded crows.     

Experimental infection of five species of raptors and of hooded crows with Francisella tularensis biovar palaearctica

Sixteen raptors and three hooded crows were infected experimentally with Francisella tularensis biovar palaearctica. The birds were infected parenterally or per os. One goshawk, one sparrow hawk and one hooded crow died during the experimental period, and the remaining 16 birds were killed 14-77 days after the first infection. Francisella tularensis was not isolated from any bird. Antibody levels against F. tularensis measured in nine birds varied from 0 to 1:1,280. In one goshawk with a titer of 1:1,280, positive fluorescent antibody reactions against F. tularensis were seen in the liver and spleen. These results are similar to those found by other authors indicating that raptors and corvids are normally resistant to infections with F. tularensis.     

Phylogeographic carrion, hooded and jungle crows (Aves, Corvidae) from data on partial sequencing of the mitochondrial DNA cytochrome B gene

Distribution of mitochondrial DNA cytochrome b gene haplotypes in two crow species was examined by means of sequencing of the 336-bp gene fragment. The topology of the NJ and UPGMA trees showed that the carrion crow range was split into two parts due to the presence of significantly diverged ancestral lineage localized in the southeastern part of the range. The carrion crow populations, inhabiting a territory ranging from France to northern Sakhalin, along with interspersed hooded crow populations and hybrid Siberian populations, shared a common haplotype. The border between two carrion crow lineages revealed is located in central Sakhalin. The subdivision of two weakly differentiated lineages within the jungle crown range, also observed within this territory, coincided with the subspecies division of this species. The estimated genetic distances indicate the isolation of the subgenus Coloeus. These data also suggest the convergent similarity between the chough Pyrrhocorax pyrrhocorax and the Corvus genus, as well as the conspecificity of Corvus corone corone and C. c. cornix.     

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 collected from 116 corvid birds of three species, i.e. jackdaws (Corvus monedula), hooded crows (Corvus corone cornix) and rooks (Corvus frugilegus), from four separate geographical locations in Sweden. Isolates were obtained by selective culture from 43 of 116 birds. All isolates were weakly hemolytic, indole-negative and lacked hippurate cleavage capacity. Examination by light microscopy did not indicate association with enteric disease in necropsied birds. Pure spirochete cultures were obtained by serial dilution and subculture, and selected isolates were analyzed by PCR (n=14), randomly amplified polymorphic DNA (RAPD) (n=14), and sequencing of the almost complete 16S rRNA (n=14), and partial nox genes (n=4). Positive reactions were noticed by PCR targeting a hexa-T segment of the 16S rRNA gene, which has been previously reported as a signature characteristic of Brachyspira pilosicoli. By 16S rRNA gene sequencing, the isolates formed a separate cluster related to genus Brachyspira, but not consistent with any presently recognized or proposed Brachyspira sp. The sequence similarity of the 16S rRNA gene among the isolates from corvid birds was 99.7-100%. Compared to 16S rRNA gene sequence data from all presently recognized and several proposed Brachyspira spp. the sequence similarity of the isolates from corvid birds varied between 94.1 and 96.5%. In a radial tree based on nox gene sequences, all four analyzed isolates from corvid birds formed a separate cluster. By RAPD analysis, the banding patterns of the isolates differed from all type strains of Brachyspira spp. Based on the results presented in this paper, we propose that the described isolates from corvid birds belong to a novel species within genus Brachyspira, with the provisional name "Brachyspira corvi" (cor'vi. L gen. n. corvi, of a crow).     

Extrapair paternity in hooded warblers

We examined the role of extrapair fertilizations (EPFs) in themating system of the hooded warbler (Wilsonia citrina), a monogamoussongbird. DNA fingerprinting revealed that 8 of 17 (47%) femaleshad extrapair young in their first or second brood, and 23 of78 (29%) nestlings were the result of EPFs. Extrapair youngwere signifkandy more likely to occur in first broods than insecond broods. The proportion of EPFs within a brood was stronglybirnodal among broods: nests had 50% or more extrapair youngor none. In seven of eight broods where EPFs occurred, an adjacentmale neighbor was identified as the actual father. Male-likecoloration in females did not reduce the likelihood of havingextrapair young. Females with extrapair young did not receiveless parental care from their mates. All males who obtainedEPFs were mated to fertile females or were feeding offspringat the time they most likely mated with the extrapair female.Our results are consistent with the female control hypothesis,which predicts that females benefit from extrapair copulations(EPCs) and have some control over which males, if any, obtainEPCs. However, we could not reject the alternative hypothesisthat some male neighbors are particularly dominant and aggressiveduring EPC attempts, so females accept these EPCs to minimizecosts.     

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 populations were significantly differentiated on microsatellites, and populations were isolated by distance over the hybrid zone in Italy. Single-locus analyses showed that one locus, CmeH9, differentiated populations on different sides of the zone at the same time as showing only weak separation of populations on the same side of the zone. Within the hybrid zone there was no differentiation of phenotypes at CmeH9 or at the set of microsatellites, no excess of heterozygotes among hybrids and low levels of linkage disequilibrium between markers. We did not detect any association between phenotypes and nucleotide variation at MC1R , and the two most common haplotypes occurred in very similar frequencies in carrion and hooded crows. That we found a similar degree of genetic differentiation between allopatric and edge populations irrespectively of their location in relation to the hybrid zone, no differentiation between phenotypes within the hybrid zone, and neither heterozygote excess nor consistent linkage disequilibrium in the hybrid zone, is striking considering that carrion and hooded crows are phenotypically distinct and sometimes recognised as separate species.     

Parallel tool industries in New Caledonian crows

Individual specialization in the use of foraging tools occurs in hunter-gatherer societies but is absent in non-human primate tool use. 'Parallel tool industries' in hunter-gatherers are mainly based on strict sexual division of labour that is highly reliant on social conformity. Here, we show that 12 individuals in a population of New Caledonian crows on Maré Island had strong preferences for either stick tools or pandanus tools. Eight of the 12 crows had exclusive preferences. The individual specialization that we found is probably associated with different foraging niches. However, in spite of sexual size dimorphism there was no significant association between the sex of crows and their tool preferences. Our findings demonstrate that highly organized, strict sexual division of labour is not a necessary prerequisite for the evolution of parallel tool industries.     

On the capability of birds for symbolization

The main approaches to studying the ability of animals to form concepts and symbolization are discussed. The available data on the capabilities of highly organized birds (parrots and corvids) to comprehend equivalence between signs and the concept of number are analyzed. The new own data on the ability of hooded crows for symbolization are described. The considered results confirm the concept that the capability for symbolization is inherent not only to higher mammals, but also to highly organized representatives of birds.     

Context-dependent tool use in New Caledonian crows

Humans and chimpanzees both exhibit context-dependent tool use. That is, both species choose to use tools when food is within reach, but the context is potentially hazardous. Here, we show that New Caledonian crows used tools more frequently when food was positioned next to a novel model snake than when food was positioned next to a novel teddy bear or a familiar food bowl. However, the crows showed no significant difference in their neophobic reactions towards the teddy bear and the model snake. Therefore, the crows used tools more in response to a risky object resembling a natural predator than to a less-threatening object that provoked a comparable level of neophobia. These results show that New Caledonian crows, like humans and chimpanzees, are capable of context-dependent tool use.     

Individual differences in facial configuration in large-billed crows

The recognition of individuals is a basic cognitive ability of social animals. A prerequisite for individual recognition is distinct characteristics that can be used to distinguish between other conspecific individuals. Studies of birds have shown that visual information, such as colour patterning, is used in individual recognition. However, in the case of monochromatic birds, colour patterning cannot be used to identify individuals. Therefore, we expected that the configuration of facial features, such as the shape of the bills or eyes, may have enough individuality to permit individual recognition in such species. In this study, we aimed to clarify visible individual differences in the facial configuration of large-billed crows (Corvus macrorhynchos). Specifically, we analysed the profile pictures of 16 crows. We measured 26 variables in 20 pictures of each bird and then performed principal component analysis and discriminant function analysis. The results showed that the configuration of the facial profiles was individually distinct, but re-classification by discriminant functions implied that it did not clearly differ between sexes. These results suggest that crows may be able to recognise individuals on the basis of the individuality of facial configuration, even in the absence of any conspicuous colour patterning.     

Mycoplasmosis in captive crows and robins from Minnesota

Mycoplasma sturni is a recently described organism previously associated with conjunctivitis in European starlings (Sturnus vulgaris), northern mockingbirds (Mimus polyglottos) and blue jays (Cyanocitta cristata). Herein we describe the isolation of M. sturni from an American crow (Corvus brachyrhynchos) presenting with conjunctivitis. A nested-PCR was designed for identification of M. sturni in clinical specimens and the sensitivity of the reaction was found to be 10 colony-changing units. The organism was found in asymptomatic American crows caged with a nestmate of the crow with conjunctivitis. Mycoplasma sturni also was found in asymptomatic American robins (Turdus migratorius) and in a European starling (Sturnus vulgaris) housed at the same facility as the crows. Heterogenity of M. sturni isolates from different host species was found by random amplified polymorphic DNA (RAPD) analyses. Heterogeneity also was found among M. sturni isolates recovered from American crows. We suggest that M. sturni can successfully infect American crows and American robins with or without the presence of clinical disease. Furthermore, we demonstrate that nested-PCR is an effective method for the detection of M. sturni and that substantial genetic heterogeneity exists among natural isolates of this bacterial pathogen.     

Genetics of barley hooded suppression

The molecular basis of the barley dominant Hooded (K) mutant is a duplication of 305 bp in intron IV of the homeobox gene Bkn3. A chemical mutagenesis screen was carried out to identify genetical factors that participate in Bkn3 intron-mediated gene regulation. Plants from recurrently mutagenized KK seeds were examined for the suppression of the hooded awn phenotype induced by the K allele and, in total, 41 suK (suppressor of K) recessive mutants were identified. Complementation tests established the existence of five suK loci, and alleles suKB-4, suKC-33, suKD-25, suKE-74, and suKF-76 were studied in detail. All K-suppressed mutants showed a short-awn phenotype. The suK loci have been mapped by bulked segregant analysis nested in a standard mapping procedure based on AFLP markers. K suppressor loci suKB, B, E, and F all map in a short interval of chromosome 7H, while the locus suKD is assigned to chromosome 5H. A complementation test between the four suK mutants mapping on chromosome 7H and the short-awn mutant lks2, located nearby, excluded the allelism between suK loci and lks2. The last experiment made clear that the short-awn phenotype of suK mutants is due to a specific dominant function of the K allele, a function that is independent from the control on hood formation. The suK loci are discussed as candidate participants in the regulation of Bkn3 expression.     

Vocal culture in New Caledonian crows Corvus moneduloides

While recent research suggests that some animal species may possess ‘cultural’ traditions, much of the current evidence for wild populations remains contentious. This is largely due to the difficulty of demonstrating a fundamental prerequisite for the existence of culture: social learning. As the only case where social learning has been demonstrated conclusively, and subsequently linked to spatial or temporal trait variation, avian vocal dialects are the best studied, and most widely accepted, form of animal culture. Here, we investigate the potential for vocal culture in one of the few animals for which material culture has been suggested: the New Caledonian crow Corvus moneduloides. We show that this species: (1) possesses the capacity for social learning of vocalizations (experimental evidence in the form of a captive subject that reproduces human speech and other anthropogenic noises); and (2) exhibits significant large‐scale, population‐level variation in its vocalizations (cross‐island playback experiments, with analyses controlling for a substantial set of potentially confounding variables). In combination, this provides strong evidence for the existence of ‘culture’ in these birds. More specifically, our findings reveal that the species exhibits sufficient social learning mechanisms, and within‐population structuring, to generate and perpetuate cultural variation in at least one behavioural domain. This is a critical first step towards demonstrating cultural transmission in other behaviours, including tool manufacture and tool use, opening the door for the simultaneous investigation of vocal and material culture in a nonhuman species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 767–776.     

Lateralized tool use in wild New Caledonian crows

Many vertebrate species exhibit sensory and motor asymmetries. Laterality studies of tool use have focused on primates, where hemispheric asymmetries, manifested behaviourally in hand preferences, are thought to be associated with complex motor tasks. Here we report strong individual lateralization for tool use in birds. New Caledonian crows, Corvus moneduloides, hold stick tools with their bills while foraging, often with the nonworking end laterally positioned on one side of the head and the working end possibly positioned in the binocular field. We observed four wild crows to determine whether tools were consistently held on one side. All crows showed a significant preference (two right, two left). This preference was independent of any asymmetry in tool manufacture and held for artificial holes similarly accessible for tools held on either side. This is the first demonstration of lateralized tool use in a nonprimate. In addition, all 173 tools used unilaterally were held only on a crow's preferred side. Such pronounced individual laterality for tool use in natural conditions has previously been reported only in humans and chimpanzees.     

Rabies in hooded and striped skunks in Arizona

Arizona is home to four species of skunks, and rabies is enzootic in the region in which their ranges overlap. Examination of state health data from 1985 to 2004 revealed an irregular 4-10 yr periodicity in the number of cases annually, which may be related to past precipitation patterns. The number of rabid skunks peaked during springtime. Locations of rabies epizootics changed over time, but there was no evidence of a large-scale geographic spread. Skunks live-trapped during 1996-2002 had a low prevalence of rabies-virus neutralizing antibodies. This study was the first to document rabies in hooded skunks (Mephitis macroura).