American Crow (Corvus brachyrhynchos)

2020 ◽  
Vol 22 (2) ◽  
pp. 109
Author(s):  
Lewke
Keyword(s):  
American Crow ◽  
Corvus Brachyrhynchos

scholarly journals West Nile Virus Devastates an American Crow Population

The Condor ◽  
2005 ◽  
Vol 107 (1) ◽  
pp. 128-132 ◽  
Author(s):  
Carolee Caffrey ◽  
Shauna C. R. Smith ◽  
Tiffany J. Weston
Keyword(s):  
West Nile Virus ◽  
North America ◽  
Late Summer ◽  
Total Loss ◽  
West Nile ◽  
American Crow ◽  
Corvus Brachyrhynchos ◽  
American Crows

Abstract In its spread west across North America in 2002, West Nile virus (WNV) reached a population of marked American Crows (Corvus brachyrhynchos) in Stillwater, Oklahoma, in late summer. Within two months, 46 of 120 individuals were missing or known to be dead, 39 of which (33% of the population) are estimated to have died for WNV-related reasons. In 2003, 56 of 78 marked crows disappeared or were found dead between June and November. Five of the 28 juvenile losses were possibly unrelated to WNV, thus we estimate that 65% of our population died because of this pathogen in 2003. The total loss of 72% of population members, including 82% of juveniles, in a single year of WNV exposure raises concern for precipitous declines in American Crow populations in coming years. El Virus del Nilo Occidental Devasta una Población de Corvus brachyrhynchos Resumen. En su diseminación hacia el oeste de América del Norte durante 2002, el Virus del Nilo Occidental alcanzó a fines del verano una población marcada de Corvus brachyrhynchos en Stillwater, Oklahoma. En menos de dos meses, 46 de los 120 individuos registrados desaparecieron o murieron, 39 de los cuales (33% de la población) estimamos que murieron por causas relacionadas con el virus. En 2003, 56 de los 78 cuervos marcados desaparecieron o fueron encontrados muertos entre junio y noviembre. Cinco de las 28 pérdidas de juveniles posiblemente no estuvieron relacionadas con el virus, por lo que estimamos que el 65% de nuestra población murió a causa de este patógeno en 2003. La pérdida total del 72% de los miembros de la población, incluyendo el 82% de los juveniles, en un solo año de exposición al virus plantea preocupaciones en cuanto a la posibilidad de una disminución precipitada de las poblaciones de C. brachyrhynchos en los próximos años.

scholarly journals The Inflected Alarm Caw of the American Crow: Differences in Acoustic Structure Among Individuals and Sexes

The Condor ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 518-529 ◽  
Author(s):  
Jessica L. Yorzinski ◽  
Sandra L. Vehrencamp ◽  
Kevin J. McGowan ◽  
Anne B. Clark
Keyword(s):  
Individual Differences ◽  
Function Analysis ◽  
Acoustic Measurements ◽  
American Crow ◽  
Acoustic Structure ◽  
Corvus Brachyrhynchos ◽  
Call Structure ◽  
American Crows ◽  
The Status ◽  
Family Membership

Abstract Previous research on individual differences in the acoustic structure of vocalizations and vocal recognition has largely focused on the contexts of parent-offspring interactions, territory defense, sexual interactions, and group cohesion. In contrast, few studies have examined individual differences in the acoustic structure of mobbing and alarm calls. The purpose of this study was to explore individual differences in the acoustic structure of the inflected alarm caw of the American Crow (Corvus brachyrhynchos). The alarm caws of 15 wild, marked individuals were recorded and 25 acoustic measurements were made automatically using customized software. A stepwise discriminant function analysis showed that 20 of the 25 variables were important in discriminating among individuals, with 65% classification success. We used factor analysis to reduce the large number of variables to a set of seven meaningful call features. All of these features differed among individuals, suggesting that American Crows have the potential to discriminate among individual birds on the basis of call structure alone. Five of the features differed between the sexes, with call frequency being the most significant. One clearly subordinate male clustered with the females, raising the possibility that social status partially determines the sex-based differences. Encoding of individual identity in alarm contexts may be adaptive if receiver vigilance and approach urgency depend on the status, reliability, or family membership of the alarm signaler.

American Crow (Corvus brachyrhynchos)

2002 ◽  
Author(s):  
N. A. Verbeek ◽  
C. Caffrey
Keyword(s):  
American Crow ◽  
Corvus Brachyrhynchos

American Crow (Corvus brachyrhynchos)

2020 ◽  
Author(s):  
N. A. Verbeek ◽  
C. Caffrey
Keyword(s):  
American Crow ◽  
Corvus Brachyrhynchos

Critical Properties of the Assembly Call of the Common American Crow

Behaviour ◽  
1978 ◽  
Vol 64 (3-4) ◽  
pp. 184-203 ◽  
Author(s):  
Nicholas S. Thompson ◽  
David B. Richards
Keyword(s):  
Sound Source ◽  
Traditional View ◽  
High Rate ◽  
American Crow ◽  
Corvus Brachyrhynchos ◽  
Temporal Properties ◽  
Series Of Experiments ◽  
The Common ◽  
Functional Context ◽  
Better Than

AbstractAccording to tradition, the communication system of the American crow, Corvus brachyrhynchos, consists of an assortment of distinct sounds each of which is used in a particular context and has a unique meaning. Despite this traditional view, we have made field observations which suggested that the sounds employed in various different functional contexts overlap considerably. These observations further suggested that each sound does not have a single unique meaning, but that its meaning varies depending upon how it and similar sounds are temporally organized into calling sequences. In order to investigate this idea, a series of experiments were performed in which the temporal properties of natural sounds recorded from crows in the field were changed. These experiments were concerned primarily with the vocalization known as the assembly call. The assembly call consists of series of sounds which are low, harsh, and variable in pitch and timing. Broadcast to crows in the field, recorded assembly calls provoke an aggregation of crows to the sound source about twenty-five percent of the time. The recordings broadcasted were of two sorts: sequences made up by modifying the temporal properties of a natural assembly call and sequences of sounds derived from calls given in other functional contexts which were then rearranged to approximate the temporal properties of an assembly call. These calls were tested on wild crows in the field. A presentation of a call was counted successful if at least one crow approached the sound source on a direct line. Different calls were compared with respect to the proportion of successful presentations. The results show that not all types of crow sounds can be manufactured into effective assembly calls. A high pitched call, even when arranged to approximate the temporal properties of the assembly call does not assemble crows at rates approaching the rate of assembly to natural assembly calls. On the other hand, the results also show that a sound need not be derived from an assembly call in order to be arranged into an effective assembly call. A call recorded in another functional context, but which has a harsh, grainy quality will assemble crows as well as or better than an assembly call if it is presented in the proper temporal arrangement. In fact, the highest rates of success were provoked by a sequence of such sounds having a high rate of emission and organized into short cycles of increasing rate. Such a call is two to four times more effective than a natural assembly call. These results are inconsistent with the traditional view that each particular caw in the repertoire of a crow has a discrete stable meaning. An alternate hypothesis is suggested in which the meaning of a sequence of crow sounds is thought to depend not only on the properties of the caws but upon the temporal properties of the sequence as well.

DNA VACCINATION OF THE AMERICAN CROW (CORVUS BRACHYRHYNCHOS) PROVIDES PARTIAL PROTECTION AGAINST LETHAL CHALLENGE WITH WEST NILE VIRUS

2007 ◽  
Vol 2 (2) ◽  
pp. e6-e6
Author(s):  
Michel L. Bunning ◽  
Patricia E. Fox ◽  
Richard A. Bowen ◽  
Nicholas Komar ◽  
Gwong-Jen J. Chang ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Dna Vaccination ◽  
West Nile ◽  
American Crow ◽  
Lethal Challenge ◽  
Partial Protection ◽  
Corvus Brachyrhynchos
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