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At least 19 recordsLinked to original sources

PubMed2002

Early season crow mortality as a sentinel for West Nile virus disease in humans, northeastern United States.

The 1999 New York epidemic of human West Nile virus (WN) encephalitis and meningitis was preceded by a crow die-off also caused by WN infection. As one component of the subsequently developed national surveillance system, crow mortality data were collected to detect WN activity before humans might become infected. However, predicting areas at risk for human WN disease likely requires assessment of multiple factors, including the intensity and timing of crow epizootics. To identify early season measures of WN activity in crows associated with subsequent WN disease in humans, county-level crow mortality data from seven northeastern states were analyzed. A predictive model was developed based on analysis of 2000 surveillance data and then assessed for 2001. To characterize the intensity of early season WN activity in crows, 15 variables were constructed from surveillance data of 52 counties that tested at least four crows during the early season (defined as June 17-July 28, 2000). County values for each variable were dichotomized at the 75th percentile into "high" and "low" activity. Multivariate analysis indicated that "high" early season activity of two variables-density of reported dead crow sightings (reported dead crows/area) and [(WN-infected crows/tested crows) x (human population)]--were associated with report of at least one human WN disease case (for each variable: adjusted odds ratio, 6.9; 95% confidence interval, 1.2-40.6). An assessment of this model using 2001 surveillance data from 61 counties yielded similar findings. With emphasis on early season WN activity, crow surveillance may allow timely targeting of interventions to protect the public health.

Animals↗

PubMed2004

The evolutionary origin of long-crowing chicken: its evolutionary relationship with fighting cocks disclosed by the mtDNA sequence analysis.

Chickens with exceptionally long crow are often favored all over the world, and connoisseur breeders have bred certain types of chicken exclusively for this trait. In Japan, three chicken varieties have been specifically bred to develop an exceptionally long crow of over 15 s. Although these three long-crowing chickens, Naganakidori, are honored as heritage varieties of Japan, the domestication process and genealogical origin of long-crowing chickens remain unclear. The purpose of this study is to clarify these issues using nucleotide sequences of the mitochondrial DNA D-loop region. Blood samples from a total of nine long-crowing chickens and 74 chickens from 11 Japanese native varieties were collected. DNA sequence data of two Junglefowl species were also collected from the International DNA database (DDBJ /EMBL/GenBank) for use as the outgroup. A phylogenetic tree was then constructed revealing that all three Naganakidori varieties were monophyletic and originated from a fighting cock, a Shamo, for cockfighting. These results suggest that these three long-crowing chickens share a common origin in spite of their conspicuously different characters, and that human cultures favoring long-crowing chickens might have been preceded by a tradition of cockfighting. Moreover, these long-crowing varieties first separated from the fighting cocks of Okinawa, which is geographically closer to Southern China and Indochina than Mainland Japan (Honshu/Kyushu). This implies that Japanese long-crowing chickens were first brought to Mainland Japan as fighting cocks from the surrounding regions of Southern China or Indochina and through Okinawa.

Aggression↗

PubMed2004

Effects of estrogens during embryonal development on crowing in the domestic fowl.

In the domestic fowl, crowing is typically a male-specific vocal behavior while the females normally do not crow. These sex differences in vocalization may result from organizational actions of estrogens during specific periods of embryonic development. To further investigate the role of estrogens in differentiation of crowing and development of the acoustic characteristics of crow calls, male domestic fowls were treated on Incubation Day 8 with estradiol benzoate (EB) or either oil or saline vehicles. On the same incubation day, the female fowls were treated with an aromatase inhibitor, fadrozole, or saline vehicle. An adulthood vocalization of cocks and hens was recorded during corresponding tests of sexual behavior. The exposure to EB or fadrozole had no effect on sexual differentiation of the gonads and all fadrozole-treated hens laid eggs at a rate similar to the control hens that received saline. While the levels of plasma testosterone at adulthood did not differ in treated and untreated cocks, the incidence of crowing rate was significantly lower in cocks that were exposed to estradiol. Acoustic analysis revealed a considerable reduction in duration and acoustic energy of calls while the main frequency characteristics were not changed. Four out of the seven tested fadrozole-treated hens demonstrated regularly crow-like vocalization with shorter duration and lower energy of calls in comparison to crows of the control males. These findings point out to a role for estradiol in organization of crowing behavior and a specific temporal pattern of the crowing call.

Androgens↗

PubMed2005

Effects of androgens and estrogens on crowings and distress callings in male Japanese quail, Coturnix japonica.

In male Japanese quail, crowing behavior is considered to be strictly androgen-dependent. It was previously shown that in chicks, treatment with either testosterone or 5alpha-dihydrotestosterone (5alpha-DHT; a non-aromatizable androgen) induced crowing with motivation for distress calling in acutely isolated conditions. Many studies, however, have shown that the potencies of testosterone and 5alpha-DHT in activating crowing in castrated males are different. To clarify the effects of androgenic and estrogenic actions on the production of crows and distress calls, we injected quail daily from 11 to 42 days after hatching (Day 11 to 42) with testosterone propionate (TP), 5alpha-DHT, estradiol benzoate (EB) or vehicle and examined their calling behaviors both in a recording chamber (acutely isolated conditions) and in their home-cages (well-acclimated conditions). Both TP- and 5alpha-DHT-treated birds began to crow by Day 13 when isolated in the recording chamber. The TP-treated birds, however, crowed less frequently than 5alpha-DHT-treated ones. This, combined with the observations that distress calling was strongly inhibited in EB-treated birds, suggests that estrogen converted from testosterone may inhibit the motivation for distress calling. On the other hand, after chronic treatment of TP, but not of 5alpha-DHT, birds began to crow intensely in their home-cages earlier than vehicle treated controls, suggesting that estrogen is needed to initiate crowing behavior in sexually active males. Taken together, it is suggested that estrogenic actions affect the motivation underlying vocal behaviors, while the androgenic action is indispensable in generating crowing.

Aggression↗

PubMed2001

Classification of hybrid crows in quail using artificial neural networks.

In galliforms, calls are strongly determined genetically and no influence of learning has ever been demonstrated. Hybridization is a useful tool for investigating patterns of heritability. The vocal repertoire of the European quail (Coturnix c. coturnix) and of the Japanese quail (C. c. japonica) are similar except for their crows. The European quail possesses two forms of crows and the Japanese quail only one form. We produced hybrids from the following crosses; F(1), F(2) and backcrosses. Visual analysis of spectrograms showed that hybrid crows presented all intermediaries between the three forms of crows produced by the two subspecies. According to the level of analysis of a crow, visual classifications of spectrograms probably include some subjectivity. Artificial Neural Networks (ANN) are now widely used as a powerful classification technique in behavioural sciences. We trained an ANN to recognize the three crows of the two subspecies. Then we analysed its classification of hybrid crows. The ANN revealed important inter-individual variability between the crows of the F(1) and the F(2) crosses. Birds issued from backcrosses produced crows similar to those of the European quail to which they were backcrossed. This study confirms that ANN is a useful tool to classify spectrograms rapidly.

Journal Article↗

PubMed1990

Prevalence of thermophilic campylobacters in crows (Corvus levaillantii, Corvus corone) and serogroups of the isolates.

A total of 500 fecal droppings of crows collected from a seashore of an ocean bay and from a cemetery on a hill surrounded by a forest were examined for thermophilic campylobacters, and the Skirrow's biovars and Penner's serogroups of the isolates were determined. The organisms were isolated from 169 (62.6%) of 270 seashore crow samples and 106 (46.1%) of 230 cemetery crow samples. During the investigation period from May 1986 to April 1987, the monthly isolation rate of thermophilic campylobacters in the seashore crow varied from 32.0 to 85.0%. C. jejuni, C. coli, and C. laridis were isolated from 150, 21 and 14 samples, respectively. In case of the cemetery crow, the monthly isolation rate varied from 20.0 to 75.0%, and C. jejuni, C. coli, and C. laridis were detected from 80, 12 and 16 samples, respectively. Among 192 strains of C. jejuni selected from 98 seashore and 57 cemetery crow samples, 106 (93.0%) of 114 seashore crow strains and 69 (88.5%) of 78 cemetery crow strains were identified as Skirrow's biovar I. Of 192 strains of C. jejuni serogrouped, 169 strains were classified into 20 serogroups. The Penner's serogroup 2, one of common serogroups among poultry and human isolates in Japan, was the most predominant in crow strains.

Animals↗

PubMed2003

[Genetic diversity of carrion and jungle crows from RAPD-PCR analysis data].

RAPD-PCR analysis of the genetic diversity of the carrion crow (Corvus corone) and jungle crow (C. macrorhynchos) living in the continental parts of their species ranges and on some Russian and Japanese Far Eastern islands has been performed. Taxon-specific molecular markers have been found for each species. The genetic diversity of the carrion crow is considerably less than that of the jungle crow at the same genetic distance (P95 = 68.2%, DN = 0.27 and P95 = 88.4%, DN = 0.24, respectively). In both species, the genetic polymorphism of island samples is almost two times greater than that of continental samples (62 and 31.8%, respectively, for C. corone and 81.5 and 47.2%, respectively, for C. macrorhynchos). In addition, differences in genetic diversity between males and females (P95 = 55.1 and P95 = 72.1, respectively) has been found in the carrion crow but not in the jungle crow. The gene diversity of C. macrorhynchos is greater than that of C. corone: the mean numbers of alleles per locus are 2 and 1.81, effective numbers of alleles are 1.62 and 1.43, and the mean expected heterozygosities are 0.39 and 0.30, respectively. The phenograms and phylograms significantly segregate the clusters of the carrion and jungle crows. The clustering patterns of carrion crows corresponds to the intraspecies taxonomic and geographic differentiation: subspecies C. c. corone and C.c. orientalis living in the western and eastern parts of the species range, respectively, form different subclusters. The cluster of the jungle crow does not exhibit differentiation into subspecies C. m. mandshuricus and C. m. japonensis; molecular genetic differences between them are small.

Animals↗

PubMedDate not supplied

[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.

Animals↗

PubMed2006

The right tool for the job: what strategies do wild New Caledonian crows use?

New Caledonian crows Corvus moneduloides (NC crows) display sophisticated tool manufacture in the wild, but the cognitive strategy underlying these skills is poorly understood. Here, we investigate what strategy two free-living NC crows used in response to a tool-length task. The crows manufactured tools to extract food from vertical holes of different depths. The first tools they made in visits were of a similar length regardless of the hole depth. The typical length was usually too short to extract food from the deep holes, which ruled out a strategy of immediate causal inference on the first attempt in a trial. When the first tool failed, the crows made second tools significantly longer than the unsuccessful first tools. There was no evidence that the crows made the lengths of first tools to directly match hole depth. We argue that NC crows may generally use a two-stage heuristic strategy to solve tool problems and that performance on the first attempt in a trial is not necessarily the 'gold standard' for assessing folk physics.

Analysis of Variance↗

PubMed2005

Bioaccumulation of organochlorines in crows from an indian open waste dumping site: evidence for direct transfer of dioxin-like congeners from the contaminated soil.

To assess the significance of waste dumping sites as a source of chemical contamination to ecosystems, we analyzed the residue levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and other organochlorines in the breast muscle of crows from a dumping site in the south of Chennai city, South India. Crows from the dumping site contained significantly higher total TEQs (60 +/- 27 pg/g lipid wt) than those from the reference sites (26 +/- 18 pg/g lipid wt). Especially, certain dioxin-like coplanar PCB congeners (Co-PCBs), such as CB-77 and CB-105, whose source is commercial PCBs,were significantly higher in crows from the dumping site than those from the reference sites. Profiles of PCDDs/DFs and Co-PCBs in crows from the dumping site were similar to those of soil at the same site, which was confirmed by principal component analysis. Furthermore, significant positive correlations were obtained between the congener-specific bioconcentration factors (BCFs) of PCDDs/DFs estimated from concentrations in crows and soil from the dumping site and the theoretical BCFs calculated from water-particle and lipid-water partitioning coefficients. On the other hand, the estimated BCFs had significant negative correlations with the molecular weight of PCDDs/DFs, indicating that molecular size limits their bioaccumulation. These results suggest that dioxin-like congeners in the soil of the dumping site were transferred directly to the crows through the ingestion of on-site garbage contaminated with soil, rather than through trophic transfer in the ecosystem. The present study provides insight into the ecological impacts of dumping sites.

Animals↗

PubMed2004

Transitive responding in hooded crows requires linearly ordered stimuli.

Eight crows were taught to discriminate overlapping pairs of visual stimuli (A+ B-, B+ C-, C+ D-, and D+ E-). For 4 birds, the stimuli were colored cards with a circle of the same color on the reverse side whose diameter decreased from A to E (ordered feedback group). These circles were made available for comparison to potentially help the crows order the stimuli along a physical dimension. For the other 4 birds, the circles corresponding to the colored cards had the same diameter (constant feedback group). In later testing, a novel choice pair (BD) was presented. Reinforcement history involving stimuli B and D was controlled so that the reinforcement/nonreinforcement ratios for the latter would be greater than for the former. If, during the BD test, the crows chose between stimuli according to these reinforcement/nonreinforcement ratios, then they should prefer D; if they chose according to the diameter of the feedback stimuli, then they should prefer B. In the ordered feedback group, the crows strongly preferred B over D; in the constant feedback group, the crows' choice did not differ significantly from chance. These results, plus simulations using associative models, suggest that the orderability of the postchoice feedback stimuli is important for crows' transitive responding.

Animals↗

PubMed2004

Differential virulence of West Nile strains for American crows.

Crow deaths were observed after West Nile virus (WNV) was introduced into North America, and this phenomenon has subsequently been used to monitor the spread of the virus. To investigate potential differences in the crow virulence of different WNV strains, American Crows were inoculated with Old World strains of WNV from Kenya and Australia (Kunjin) and a North American (NY99) WNV genotype. Infection of crows with NY99 genotype resulted in high serum viremia levels and death; the Kenyan and Kunjin genotypes elicited low viremia levels and minimal deaths but resulted in the generation of neutralizing antibodies capable of providing 100% protection from infection with the NY99 strain. These results suggest that genetic alterations in NY99 WNV are responsible for the crow-virulent phenotype and that increased replication of this strain in crows could spread WNV in North America.

Animals↗

PubMedDate not supplied

Involvement of a midbrain vocal nucleus in the production of both the acoustic and postural components of crowing behavior in Japanese quail.

Many bird species produce vocalizations which are accompanied by distinctive postural displays, but the neural mechanisms that allow such integrated production of vocal and postural motor patterns are not understood. In the crowing behavior of Japanese quail, a characteristic vocal pattern is accompanied by and coordinated with a postural display that consists of a sequence of rapid, patterned head movements. The purpose of the present study was to investigate the role of a midbrain vocal nucleus, the nucleus intercollicularis, in the production of the acoustic and postural components of crowing in quail. Brief electrical stimuli were applied to the nucleus intercollicularis during spontaneously emitted crows in quail with chronically implanted electrodes, to determine if perturbing neural activity in the nucleus intercollicularis resulted in a disruption of ongoing crowing behavior. The most common effect of such stimuli was a concurrent, premature termination of both the acoustic and head movement components of the crow. These results imply that the nucleus intercollicularis plays a role in the production of both the acoustic and postural components of crowing in quail.

Animals↗

PubMed2003

Prototype symbolization in hooded crows.

Studies were undertaken to determine whether four crows previously trained to an image-based abstract selection rule could establish a relationship between the number of elements in a group and initially indifferent symbols (arabic numerals) and operate with these symbols, i.e., studies addressed the ability of these birds to symbolize. Unlike other similar studies, there was no use of special development of associative connections between the symbols and the corresponding arrays of elements, but conditions were created in which birds could observe these relationships on the basis of comparison with previously obtained information. Demonstration series were performed for this purpose, in which correct solutions by the crow resulted in receipt of a number of larvae corresponding to the number of elements in the array pictured or numeral imaged on the stimulus selected by the crow. Images belonged to the same category as the corresponding stimulus for selection (the second stimulus was another category): if the image was an array, then the corresponding picture for selection also bore an array, and vice versa. Crows could solve the task successfully by using an image-based selection rule. In test series, the image and both selection stimuli were initially from different categories: if the image was a numeral, then both selection stimuli were arrays, and vice versa. All four crows successfully coped with this task. Despite the absence of any similarity between the image and "correct" stimulus, they selected the array corresponding to the numeral and vice versa. It is suggested that the birds could achieve this result by comparing the information obtained during the presentation series--about the number of reinforcement units corresponding to each stimulus. Similar experiments showed that crows could use numbers to perform operations analogous to arithmetic addition.

Animals↗

PubMed2001

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.

Animals↗

PubMed1992

Aprocta matronensis in crows (Corvus corone corone) from northern Italy.

Aprocta matronensis (Nematoda, Spirurida) has been found in the orbital cavities of carrion crows. Hooded crows and crows from the hybrid crow zone in the studied areas were not infected. The parasite population showed the typical morphology described for this species. This is the first record of A. matronensis in crows in Italy and in Corvus corone corone. Some hypotheses about the distribution of the parasites in crow populations are discussed.

Animals↗

PubMedDate not supplied

[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 varied (in a half of presentations the greater array consisted of bigger elements while the lesser array consisted of smaller elements and in the other half the greater array consisted of smaller elements while the lesser array consisted of bigger elements). All the crows demonstrated high accuracy of comparisons (75.3 +/- 2.4%). Correct performance dominated also under conditions with minimal difference between the compared arrays. It was concluded that these crows were able to compare the arrays in the range of 1-12 by numerosity itself. When arrays in the new range of 10-20 were presented all the crows demonstrated successful transfer of acquired reaction without any additional training (71.5 +/- 2.3%). However, when the ratio of cumulative area of elements to their number varied only two of the four crows performed successfully (71.9 +/- 3.6). Taken together these data suggest that crows are capable of forming the concept "more than" based on numerical discrimination up to 20.

Animals↗

PubMed2005

Thyroid lesions and dioxin accumulation in the livers of jungle crows (Corvus macrorhynchos) in urban and suburban Tokyo.

Wild jungle crows (Corvus macrorhynchos) captured from three different areas of Tokyo were examined to evaluate environmental contamination of dioxins. In addition to the pathologic examination of their whole body, accumulation of dioxins, mRNA expression of the aryl hydrocarbon receptor (AhR), and pentoxyresorufin-O-depenthylase (PROD) activity in the liver were determined. Marked histopathologic changes were observed in the thyroid glands, especially in the crows from the urban downtown area. Levels of dioxins and their toxic equivalents (TEQs) and AhR mRNA expression in the livers of the crows from the urban area were higher than those from the suburban area. There was a high correlation between the levels of TEQs and PROD activity. The results of the present study demonstrated that jungle crows possess AhR-mediated toxicologic pathways similar to those of mammals and suggest the possibility that the thyroidal changes observed in the adult crows from the urban areas are one of the toxic manifestations resulting from exposure to dioxins and other environmental chemicals.

Age Factors↗