Variation in the temporal characteristics of the vocalizations of bullfinches, Pyrrhula pyrrhula.

Temporal characteristics of the vocalizations of bullfinches were investigated. The calls produced by experimentally isolated bullfinches were subjected to sonagraphic analysis. Within individual, between individual, and local variation in these calls was demonstrated. Several categories of calls were described, of which those termed "sequence calls" contained the greatest amount of information on which individual recognition could be based. Contact calls were individually distinctive in terms of their duration but with the exception of those produced by one female these lacked the structural complexity and information content of the sequence calls.