The first experiences are very promising: the vocal imprinting seems to be much more powerful than pure visual imprinting (after hatching): whereby it was very complicate in earlier trial projects to bring the young cranes to follow the airplane in the first weeks (because they preferred to stay the ground together with the - costumed - caretaker), they now followed the subject or object making the "contact" call. It is easy to tell the cranes to follow the airplane or the caretaker, to go in or out of the fenced area. It was even possible to call a group of young cranes back to the training centre when they had been "kidnapped" by a wild crane pair.
ConclusionsT he new sonographical method for identifying cranes provides a relatively simple and easy to handle tool for identifying and monitoring cranes and their life (partner and territory fidelity) It also allows to count how many different crane pairs are present in a certain area, much easier than by just visual observations.
The collection of recordings made by systematic visits to the areas in question especially early in the morning, but also statistically distributed over the days gives a picture of the minimum number of pairs (and individuals) present in the area under supervision.
Wherever it is not possible or not advisable to band (which is the majority of areas) this method is the only method which can be practically applied by almost every ornithologist or observer.
A long term monitoring of cranes leading to individual life history facts is possible.
All these advantages without even touching the cranes, from distances between their flight distance up to several kilometres.