SIGNS OF HUNGER IN CALLS OF SIBERIAN CRANE (GRUS LEUCOGERANUS, GRUIDAE) CHICKS

Chicks can convey information about their needs in food through their calls. However, it is still unclear if there are any universal acoustic markers of chick's hunger. Here we tested experimentally whether acoustic call variables of human-raised Siberian crane chicks (Grus leucogeranus) are related to their hunger level. All measured frequency parameters (except for the minimum fundamental frequency) in hungry chicks were found to be significantly higher than in replete chicks. The calls of hungry chicks were noisier, longer and followed each other with smaller intervals. The total time spent by hungry chicks on the vocal activity was also greater than the time spent by replete chicks, although this difference is insignificant. The possibility to use our data for the determination of universal vocal indicators of needs in birds is discussed, as well as the importance of them for automatic acoustic monitoring of the hunger level when rearing cranes in captivity.