Kapitel 3: Individuelles Kennenlernen, Verhalten und Intelligenz
- based on "mathematica 4.0" (Wolfram Research), with a specially developed script [10] (protocol), a so-called "powerspectrum" is calculated (which is the plot of the intensities at certain frequencies, derived from the addition of all intensities at these frequencies over the time of the recorded call); these results are data, or better: lists of data, which can be analysed and compared. This analysis is preferably made between 600 and 1200 Hz at a very high resolution, and can be changed according to needs (e.g., there are cranes which call below 600 or above 1200 Hz). (With this program also sonograms are created which are now available as 3-dimensional lists of data - frequency, time, intensity - for further analysis in the powerspectrum, but not yet in the sense of a pattern or image analysis.)
The "powerspectrum" was considered by me to be a "vocal fingerprint" based on the fact, that the properties of the sound generating organ (the trachea) will determine the frequency spectrum of the generated sounds of an adult crane (after complete development of the voice).
Results (1): identification of crane individuals / pairs
A
n identification of cranes and crane pairs would be feasible, if (a) call characteristics are stable enough within one season and from year to year (b) the are different enough to differentiate them from calls expressed by other cranes or crane pairs. In 1998, about 200 files from 7 pairs in their territories and outside of it, one adult unpaired male, and a few calls of unpaired youngsters had been recorded from late March to May.
