SOUND DESIGN FOR VOCALIZATIONS: QUALITY IN THE WOODS, CONSISTENCY IN THE FIELDS

Abstract The acoustic adaptation hypothesis (AAH) predicts that vocalizations intended for unambiguous long range communication should possess amplitude modulation (AM) characteristics such that the temporal patterning of amplitude degrades less than alternative patterns during transmission through native habitat. The specific predictions are that open habitat signals should be structured as rapid AM trills, whereas closed habitat signals should be structured as low-rate AM tonal whistles. To investigate the benefit of trill- and whistle-structured signals in open and closed habitats, respectively, a high and low carrier frequency set of four synthetic signals which ranged from rapid AM trills to low rate AM whistles were transmitted 3 hours after sunrise through five different habitat types ranging from closed mature forest to open grassland. Results indicate that, on average, whistles degrade less than trills in both habitats. Trills benefit in open habitats through their tendency to be received with a more consistent quality than whistles. Such differences in transmission consistency among AM patterns are not found in closed habitats. While not degrading less on average, lower frequency signals are received with a more consistent quality than are higher frequency signals of the same AM structure, in both open and closed habitats.

[1]  M. E. Anderson,et al.  NORTHERN CARDINAL SONG IN THREE FOREST HABITATS IN EASTERN TEXAS , 1985 .

[2]  E. Morton.  Ecological Sources of Selection on Avian Sounds , 1975, The American Naturalist.

[3]  Jorma Sorjonen,et al.  Factors Affecting the Structure of Song and the Singing Behaviour of Some Northern European Passerine Birds , 1986 .

[4]  Marc Naguib.  Ranging of songs with the song type on use of different cues in Carolina wrens: effects of familiarity , 1997, Behavioral Ecology and Sociobiology.

[5]  John R. Krebs,et al.  The reaction of great tits (Parus major) to playback of degraded and undegraded songs: the effect of familiarity with the stimulus song type , 1983 .

[6]  P. Handford.  Trill rate dialects in the Rufous-collared Sparrow, Zonotrichia capensis, in northwestern Argentina , 1988 .

[7]  Laurene M. Ratcliffe,et al.  SONG DEGRADATION AND ESTIMATION OF ACOUSTIC DISTANCE IN BLACK-CAPPED CHICKADEES (PARUS ATRICAPILLUS) , 1995 .

[8]  R. H. Wiley,et al.  Reverberations and Amplitude Fluctuations in the Propagation of Sound in a Forest: Implications for Animal Communication , 1980, The American Naturalist.

[9]  J. D. Crawford,et al.  Sound production and reproductive ecology of strongly acoustic fish in Africa: Pollimyrus isidori, Mormyridae , 1997 .

[10]  P. McGregor,et al.  Female great tits can identify mates by song , 1996, Animal Behaviour.

[11]  R. H. Wiley.  Associations of Song Properties with Habitats for Territorial Oscine Birds of Eastern North America , 1991, The American Naturalist.

[12]  Peter K. McGregor,et al.  The response of Western Meadowlarks (Sturnella neglecta) to the playback of undegraded and degraded songs , 1984 .

[13]  Poul Hansen.  Vocal learning: its role in adapting sound structures to long-distance propagation, and a hypothesis on its evolution , 1979, Animal Behaviour.

[14]  A. Badyaev,et al.  HABITAT ASSOCIATIONS OF SONG CHARACTERISTICS IN PHYLLOSCOPUS AND HIPPOLAIS WARBLERS , 1997 .

[15]  Charles H. Brown,et al.  Old world monkey vocalizations: adaptation to the local habitat? , 1995, Animal Behaviour.

[16]  S. Lougheed,et al.  VOCAL DIALECTS AND THE STRUCTURE OF GEOGRAPHIC VARIATION IN MORPHOLOGICAL AND ALLOZYMIC CHARACTERS IN THE RUFOUS‐COLLARED SPARROW, ZONOTRICHIA CAPENSIS , 1992, Evolution; international journal of organic evolution.

[17]  Marc Naguib.  Ranging By Song in Carolina Wrens Thryothorus Ludovicianus: Effects of Environmental Acoustics and Strength of Song Degradation , 1996 .

[18]  E. Morton,et al.  Song ranging by the dusky antbird, Cercomacra tyrannina: ranging without song learning , 1996, Behavioral Ecology and Sociobiology.

[19]  S. Lougheed,et al.  Variation in Duration and Frequency Characters in the Song of the Rufous-Collared Sparrow, Zonotrichia capensis, with Respect to Habitat, Trill Dialects and Body Size , 1991 .

[20]  Douglas G. Richards,et al.  ESTIMATION OF DISTANCE OF SINGING CONSPECIFICS BY THE CAROLINA WREN , 1981 .

[21]  S. I. Rothstein,et al.  Vocal Dialects and Their Possible Relation to Honest Status Signalling in the Brown-Headed Cowbird , 1987 .

[22]  Marc Naguib,et al.  Auditory distance assessment of singing conspecifies in Carolina wrens: the role of reverberation and frequency-dependent attenuation , 1995, Animal Behaviour.

[23]  Paul Handford,et al.  Acoustic signal amplitude patterns : A computer simulation investigation of the acoustic adaptation hypothesis , 1996 .

[24]  R. Haven Wiley,et al.  Ranging of conspecific songs by Kentucky warblers and its implications for interactions of territorial males , 1996 .

[25]  R. Haven Wiley,et al.  5 – Adaptations for Acoustic Communication in Birds: Sound Transmission and Signal Detection , 1982 .

[26]  Eugene S. Morton,et al.  Predictions From the Ranging Hypothesis for the Evolution of Long Distance Signals in Birds , 1986 .