Receiver psychology and the evolution of animal signals

SUCCESSFUL ACOUSTIC COMMUNICATION requires that sounds propagate through the environment between the sender and receiver; vocalizations that transmit effectively in the habitat in which they are used are favored by natural selection. This "acoustic adaptation" hypothesis (Morton 1975, Wiley and Richards 1978, Richards and Wiley 1980, Ryan and Brenowitz 1985) laid the groundwork for the "sensory drive" concept (Endler 1992), which describes how environment affects the evolution of sensory systems and signals in all modalities. By allowing us to examine animal signals as adaptations shaped by selection, this framework has lead to a greater understanding of the bewildering diversity of animal signals. One of the environmental factors that exerts selection pressure on acoustic signals is ambient noise (Ryan and Brenowitz 1985). To elicit a response from a receiver, signals must be detectable in background noise; the detectability of a signal is determined by the signal-to-noise ratio (SNR) and the masked auditory detection threshold of the receiver (Marten and Marler 1977, Brenowitz 1982, Dooling 2004). Within a given frequency band, signals with an SNR below the detection threshold of the receiver are "masked." Background noise thus plays a fundamental role in determining which "receivers" can hear a vocalization and the fidelity of the signal received. Noise varies among locations, and there is evidence that many species have evolved signals that maximize the habitat-specific SNR (reviewed in Brumm and Slabbekoorn 2005). For birds in and around urban areas and roads, the background noise is largely anthropogenic. Urban development

https://bioone.org/journals/The-Auk/volume-123/issue-3/0004-8038(2006)123[639:ACIUNC]2.0.CO;2/AVIAN-COMMUNICATION-IN-URBAN-NOISE--CAUSES-AND-CONSEQUENCES-OF/10.1642/0004-8038(2006)123[639:ACIUNC]2.0.CO;2.pdf

Avian communication in urban noise: causes and consequences of vocal adjustment

Design of Playback Experiments P.K. McGregor, et al. Playback J.B. Falls. Integrating Playback C.K. Catchpole. What Studies on Learning Can Teach Us About Playback Design I.M. Pepperberg. Conducting Playback Experiments and Interpreting their Results H.C. Gerhardt. Quantifying Responses to Playback P.K. McGregor. Interactive Playback T. Dabelsteen. Playback as a Tool for Studying Contests Between Social Groups K. McComb. Song Overproduction, Song Matching, and Selective Attrition During Development D.A. Nelson. Male Quality and Playback in the Great Tit M.M. Lambrechts. Mechanisms and Function of Call-Timing in Male-Male Interactions in Frogs G.M. Klump, H.C. Gerhardt. Measuring Responses of Female Birds to Male Song W.A. Searcy. Field Experiments on the Perception of Song Types by Birds A.G. Horn. 2 additional articles. Index.

Playback and Studies of Animal Communication

No single theory so far proposed gives a wholly satisfactory account of the origin and maintenance of bird-song dialects. This failure is the consequence of a weak comparative literature that precludes careful comparisons among species or studies, and of the complexity of the issues involved. Complexity arises because dialects seem to bear upon a wide range of features in the life history of bird species. We give an account of the principal issues in bird-song dialects: evolution of vocal learning, experimental findings on song ontogeny, dialect descriptions, female and male reactions to differences in dialect, and population genetics and dispersal.We present a synthetic theory of the origin and maintenance of song dialects, one that accommodates most of the different systems reported in the literature. The few data available suggest that large, regional dialect populations are genetically differentiated; this pattern is correlated with reduced dispersal between dialects, assortative mating by females, and male-male exclusion. At the same time, “subdialects” may be formed within regional dialects. Subdialect clusters are usually small and may represent vocal mimicry among a few adjacent territorial males. The relative importance of genetic and social adaptation may contribute to the emergence of subdialects; their distinctiveness may be correlated with the degree of polygyny, for example. Thus, subdialect formation is linked to one theory of the evolution of repertoire size, but data are too fragmentary to examine this idea critically.

The Biology of Bird-Song Dialects

https://faculty.washington.edu/beecher/Searcy%20&%20Beecher%20-%20AB2009.pdf

Karl Van Orsdol

Papers

Song matching in the great tit Parus major L.