Acoustic differentiation in the coo-vocalisations of the Collared Dove

According to their different functional contexts and accompanying visual displays, the coos of the collared dove Streptopelia decaocto can be classified into three different types. This study examined whether these coo types also differ in acoustic characteristics. A large set of temporal, frequency and amplitude characteristics was measured to determine intra-individual variation within and between the coo types. Discriminant function analyses revealed that temporal parameters were best at discriminating between the coo types. Combined with the known variation in context and visual displays a strong case can be made that the coo types of the collared dove are likely to convey different information. Comparison of intra-individual variation within and between the coo types revealed clear differences between the acoustic parameters. The fundamental frequency, which is probably primarily determined by syrinx structure, was a very stable parameter. The amplitude of coos, which may depend on the activity of the abdominal muscles, was highly variable, but did not vary systematically between the coo types. Most temporal features were stable within a coo type, but varied significantly between coo types.