The American Crow and the Common Raven

2019 ◽  
pp. 67-67
Keyword(s):  
American Crow ◽  
Common Raven ◽  
The Common

Molecular and morphological description of Sarcocystis kutkienae sp. nov. from the common raven (Corvus corax)

2020 ◽  
Vol 119 (12) ◽  
pp. 4205-4210
Author(s):  
Petras Prakas ◽  
Dalius Butkauskas ◽  
Evelina Juozaitytė-Ngugu
Keyword(s):  
Morphological Description ◽  
Corvus Corax ◽  
Common Raven ◽  
The Common

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.

Factors affecting carcass use by a guild of scavengers in European temperate woodland

2005 ◽  
Vol 83 (12) ◽  
pp. 1590-1601 ◽  
Author(s):  
N Selva ◽  
B Jędrzejewska ◽  
W Jędrzejewski ◽  
A Wajrak
Keyword(s):  
Parus Major ◽  
Weather Conditions ◽  
Nyctereutes Procyonoides ◽  
Extrinsic Factors ◽  
Factors Affecting ◽  
Gray Wolves ◽  
Common Raven ◽  
Complex Process ◽  
Pine Martens ◽  
The Common

Although facultative scavenging is very common, little is known about the factors governing carrion acquisition by vertebrates. We examined the influence of carcass characteristics, carcass state, and weather conditions on carrion use by main scavengers. Carcasses (N = 214, mainly ungulates) of various origins (predation, natural deaths, harvest) were monitored by systematic inspections (N = 1784) in Białowieża Forest (Poland). Common raven (Corvus corax L., 1758), red fox (Vulpes vulpes (L., 1758)), and European pine marten (Martes martes (L., 1758)) mainly used the prey remains of gray wolves (Canis lupus L., 1758). The kills of predators were the preferred carrion, rather than dead ungulates. Common ravens, common buzzards (Buteo buteo (L., 1758)), white-tailed eagles (Haliaeetus albicilla (L., 1758)), and domestic dogs scavenged more frequently on carcasses in open habitats. Carcasses located in the forest were the most available to European pine martens, jays (Garrulus glandarius (L., 1758)), and wild boar (Sus scrofa L., 1758). The common tendency was to increase scavenging when temperature decreased, except for raccoon dogs (Nyctereutes procyonoides (Gray 1834)). As snow depth increased, jays and great tits (Parus major L., 1758) increased scavenging. We suggest that carrion use by scavengers is not random, but a complex process mediated by extrinsic factors and by behavioural adaptations of scavengers.

Avian Play

The Auk ◽  
1977 ◽  
Vol 94 (3) ◽  
pp. 573-582 ◽  
Author(s):  
Millicent S. Ficken
Keyword(s):  
Motor Skills ◽  
Learning Process ◽  
Developmental Process ◽  
Object Manipulation ◽  
Selection Pressures ◽  
Common Raven ◽  
The Common

Abstract Play is more difficult to distinguish from other activities in birds than in mammals. Some cases of play reported in the literature appear to be due to threshold lowering, a type of activity that is usually differentiated from play. The various types of avian play are reviewed. Like mammals, birds exhibit object manipulation and some types of locomotory play. Subsong shows some remarkable similarities with characteristics of nonvocal play as noted in mammals, and birds may engage in other types of acoustic activities with playlike features. The corvids, particularly the Common Raven, exhibit the most complex play known for birds, and these activities, which are part of the learning process in the young, are probably important in the species' adaptation to a wide variety of habitats. Of all animals, only birds and mammals play, and play evolved independently in the two groups probably because of similar selection pressures acting on the developmental process to produce flexibility of behavior and the perfection of certain motor skills.

Increasing numbers of a threatened insular population of the Common Raven Corvus corax

Ostrich ◽  
2020 ◽  
Vol 91 (4) ◽  
pp. 305-312
Author(s):  
Manuel Siverio ◽  
Felipe Siverio ◽  
Beneharo Rodríguez
Keyword(s):  
Corvus Corax ◽  
Common Raven ◽  
The Common ◽  
Insular Population
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