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This book will be a landmark text for all those interested in animal communication. Animal Vocal Communication explicitly avoids human-centred concepts and approaches and links communication to fundamental biological processes instead. It offers a conceptual framework - assessment/management - that allows us to integrate detailed studies of communication with an understanding of evolutionary perspectives. Self-interested assessment is placed on par with the signal production (management) side of communication, and communication is viewed as reflecting regulatory processes. Signals are used to manage the behaviour of others by exploiting their active assessment. The authors contend that it is this interplay between management and assessment that results in the functioning and evolution of animal communication; it is what communicative behaviour accomplishes that is important, not what information is conveyed.

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The Ranging Hypothesis (RH) (MORTON, 1982) proposed a form of distance assessment (ranging) based upon perception of signal degradation using memorized signals as a yardstick to distance. The predictions of the RH include distance assessment mechanisms, DAMs; it is proposed that these have opened a new evolutionary process illustrated by the complicated songs and singing behaviour in the oscine passerines ("songbirds"). The RH identifies sources of selection favouring learning, multiple or single song types, song structural complexity not accounted for by species isolating mechanism ideas, and emphasizes the ecological basis for the evolution of long distance communication. New importance is given to the acoustic physical structure of songs. The RH encompasses and contrasts song evolution in warm climate regions with those in cold temperate climates. Three interrelated stages of long distance signal evolution are presented: detectability, threat, and disrupt. A singer/listener role dichotomy in selective pressures is described and the results discussed. Listeners developed distance assessment mechanisms (DAMs) resulting in an evolutionary arms race between listeners and singers. Singers developed methods to use DAMs to their best interest (threat and disrupt). Song learning in passerines developed in response to this arms race to enhance disruption, a situation most prevalent in cold temperate zone regions. The acoustic determinants of effective song distance are described and discussed in relation to the evolution of signal structures. Finally, the RH is discussed in relation to some previous hypotheses on song function and evolution.