Zebra finches identify individuals using vocal signatures unique to each call type

Individual  recognition  is  critical  in  social  animal  communication,  but  it  has  not  beendemonstrated for a complete vocal repertoire. Deciphering the nature of individual signaturesacross call types is necessary to understand how animals solve the problem of combining, inthe same signal, information about identity and behavioral state. We show that distinctsignatures differentiate zebrafinch individuals for each call type. The distinctiveness of thesesignatures varies: contact calls bear strong individual signatures while calls used duringaggressive encounters are less individualized. We propose that the costly solution of usingmultiple signatures evolved because of the limitations of the passivefiltering properties of thebirds’vocal organ for generating sufficiently individualized features. Thus, individual recog-nition requires the memorization of multiple signatures for the entire repertoire of con-specifics of interests. We show that zebrafinches excel at these tasks.