Discrimination of Individual Voices in Male Great Bitterns (Botaurus Stellaris) in Italy

Recorded vocalizations from 18 known Great Bitterns (Botaurus stellaris) were analyzed, both quantitatively and qualitatively, to determine the amount of intra- and inter-individual variation. All parameters examined showed significant variation among males, and vocalizations of the same male were not stable over time. Variability within males over time makes re-identification of individuals on the basis of vocalizations difficult. The high degree of uncertainty in recognizing individuals limits the usefulness of vocalizations for censusing of bitterns.