Blaring trumpet calls, growls and squeaks
The Old High German name of the bird “cranuh” imitates its trumpet like calls onomatopoeically. The loud trumpeting is an unmistakable trait of the crane. In open terrain and depending on the weather adult birds can be heard across a distance of two kilometers and more.
The bird’s enormous voice volume owes to the special build and enormous length of their windpipe, which ranges across the breastbone as a double loop. The windpipe can measure up to 130cm. Since the long windpipe has to develop, the young birds can only make high squeaking sounds.
However cranes have a much larger call repertoire, which is very important for inner species communication and social behavior. Besides the trumpet like call which is also used as a warning call during flight, other cries such as the duet call and special warning calls can be clearly distinguished.
The duet call of a couple is a chronologically coordinated tone sequence made by both partners. The male e.g. begins with one to two tones and the female adds two, three or four higher notes. It is also possible that the females strikes up and the male partner joins in. During these cries the partners adopt a typical pose during which they align their head and beak upwards. Additionally both stand close to each other or move slowly next to each other during the call series. The duet can be heard during the breeding season especially but also is performed in different situations of excitation in gathering and resting areas.
If danger occurs a warning call is sounded by a couple or more birds. In couples one partner stretches its neck forward, the second follows with a deeper (male) or higher (female) sound whereupon the first bird joins in again. The result is a double call which is often heard in breeding territories and across long distances.
Mature birds solely express sharp vowel free sounds in their breeding territory which sound like growling. These are called from the ground or the air if danger is around in order to warn the young birds and induce them to flee or hide.