Several studies have described parts of the vocal repertoire of Nyctalus noctula (e.g. Pfalzer & Kusch 2003; Furmankiewicz et al. 2011). We added to the species’ vocal repertoire description by analyzing pup isolation calls (Knörnschild et al. 2007). For several years now, Silke Voigt-Heucke (FU Berlin) has been working on vocal communication in N. noctula; thus, other interesting facts about the species’ vocal repertoire are forthcoming.
Nyctalus noctula (© Mayer).
Pups produce isolation calls to solicit maternal care. We have statistical evidence that isolation calls encode an individual signature. The vocal signatures of twin pups are more similar to each other than to other age-matched pups (Knörnschild et al. 2007).
Isolation calls of N. noctula pup (© Knörnschild).
We recorded distress calls from hand-held females.
Distress calls of N. noctula (© Knörnschild).
Other vocalization types
We recorded two other vocalization types from captive females; however, their behavioral function could not be determined.
Two other vocalization types of N. noctula females (© Knörnschild).
Sonograms depict frequency as a function of time (1,024-point fast Fourier transform, 100% frame size, Hamming window with 87.5% overlap).