Language of the American Crow, Corvus brachyrhynchos.
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POSTED: November 15, 2011
The Language of Crows: The crows.net book of the American crow.
Includes the CD, "An Introduction to the Language of the American Crow."
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THE LANGUAGE OF CROWS
What we know about crow communication.
The most obvious characteristics of the American crow are that it is big, black, and makes a lot of noise. The most obvious sound that crows make is the one written in English as caw. Caws may be long or short, loud or relatively soft, given singly or in sequences, made by one bird alone or by two or more birds under a variety of circumstances.
We also know that the caws of crows can sound different to human listeners. Within the same group of crows in a limited territory, there can be considerable variation in how the caws sound to a listener, and it has also often been noted that crows in different parts of the United States sound different from each other.
In addition to the distinctive caws, crows also make a variety of other sounds including, but not limited to, imitations of sounds of other species, including elements of human speech. Of particular interest is a whole variety of other crow vocalizations that don't fit into the above categories, are fairly low volume and may be used by one crow alone or among a group of crows.
Observers over the centuries have noted that crows use specific sounds under specific circumstances. Alarm calls, assembly calls, distress calls, and many others have been noted. One problem in interpreting these calls, however, has been the fact that different groups of crows, belonging to the same species but in different geographical areas, may not use or understand all of the same calls.
Hubert and Mable Frings (1959) noted, for example, that American eastern crows that breed in Pennsylvania and winter in the southern states among fish crows will respond to the distress call of the French jackdaw, a related bird not native to any portion of their range. Eastern crows that breed in Maine and apparently never mix with other crows, however, do not react to the jackdaw calls.
Bernd Heinrich, in Ravens in Winter states the following, which seems equally true for the American crow as the Common Raven.
"We have hardly begun to decipher the language of the raven. Its dictionary so far contains but a few 'words'. Perhaps our analysis has been too coarse-grained to catch the meanings. Our research has been something like that of aliens from outer space who make sonograms of human vocalizations under different situations - eating, playing, loving, fighting, etc. Certain differences noted in frequency, intonation, and loudness are correlated with feelings and emotions. But human sounds convey much more, and perhaps ravens' do, too."
Our challenge is to put ourselves in the place of those "aliens from outer space" and solve the immensely difficult problem of how to communicate with another intelligent species.
Calls Described in the Scientific Literature
A number of calls made by crows have been described in the scientific literature over the past century. Our review has indicated that it appears nearly impossible for someone not already familiar with various types of crow vocalizations to distinguish them by means of the descriptions given in print literature. In the near future, each call will be linked to an audio recording and a sonogram to provide a precise record of each sound described.
For a listing of the calls of the American crow described in the scientific literature, please click on the following link:Vocalizations described in the scientific literature.
The illustration to the left depicts a "sonogram" (also called a spectrogram) - basically a graphic presentation of sound frequencies. This particular sonogram is of a sequence or grouping of five caws made by one crow. The crow was sitting on a branch above a feeding stating and produced several groupings of 4 or 5 caws, such as the one illustrated, with a few seconds between each grouping. It then descended and fed.
If you click on the sonogram, you should hear the call represented by the image.
The basic premise upon which we will operate is that if crows do indeed use a sophisticated form of vocal communication, analysis of the frequencty patterns in sonograms should enable us to recognize some of the "words" of this language, even if we are initially unable to assign a precise meaning to each "word".
Analysis of Crow Vocalizations
We are begining work on the analysis of crow vocalizations. This material is posted at Analysis of Crow Vocalizations. The Analysis page will be updated on a frequent basis, so check back often for the latest work-in-progress.
Sound Analysis Software
Several software programs are available for recording, displaying, and analyzing sonograms. One of the research methods we will be utilizing will be to provide links to "freeware" programs for producing sonograms, along with predetermined settings for recording and analyzing crow vocalizations. This will enable Crows.net Project participants to compare the vocalizations of crows from different locations via the internet and the Crows.net Project website.
(This section will be added to on a continuing basis. Your comments and suggestions are welcomed. Other parts of the site are also under construction. This site will be continually expanding as the Crows.net Project grows.)
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