Elsevier

Animal Behaviour

Volume 72, Issue 3, September 2006, Pages 699-705
Animal Behaviour

Animals can vary signal amplitude with receiver distance: evidence from zebra finch song

https://doi.org/10.1016/j.anbehav.2006.01.020Get rights and content

Acoustic signals attenuate with the distance over which they travel, but a vocalizing animal might maintain signal transmission by increasing vocal amplitude when addressing a distant receiver. Such behaviour is well known in humans as speakers vary vocal amplitude with changing distance from an audience, a phenomenon that has been interpreted as resulting from our higher cognitive abilities. However, whether nonhuman animals are capable of this form of vocal adjustment appears to be unknown. We investigated whether birds are also able to regulate the amplitude of their vocal signals depending on receiver distance. Male zebra finches, Taeniopygia guttata, increased their song amplitude with increasing distance to addressed females, indicating that songbirds, like humans, respond to differences in communication distance and that they adjust vocal amplitude accordingly. Our findings show that animal communication is flexible in a previously unsuspected way, and that human speech and bird song share a basic mechanism for ensuring signal transmission. We suggest that this behaviour can be accounted for by simple proximate mechanisms rather than by the cognitive abilities that have been thought necessary in humans.

Section snippets

Subjects

We tested 20 male zebra finches, which were each presented with a female. Before the experiments, male and female birds were kept separately in single-sex flocks (N = 31 males, 20 females) in two aviaries (each 1.7 × 2.5 m and 2 m high) that allowed auditory but no visual contact. Both aviaries were fitted with several natural perches, such as branches from apple or ash trees. All birds were maintained on a 12:12 h light:dark schedule under full-spectrum lights, with air temperature ranging between 20

Results

Almost all males directed song to the female when she was presented at the shortest range of 40 cm, but fewer males did so with increasing communication distance (chi-square test: χ32=12.74, P < 0.01; Fig. 2). Between males, the number of song elements per phrase varied from three to nine, with the majority of birds (N = 8) having five. Zebra finches have only one song type, and all birds sang the same song invariably (i.e. the same number of elements per phrase, with the same syntax), regardless of

Discussion

This study found that male zebra finches were more likely to direct song to females that were in closer proximity. This result supports the hypothesis from field observations (Zann 1996) that directed song is a short-range signal. Furthermore, males adjusted their song amplitude depending on the communication distance so that they produced louder songs when the addressed female was further away. This result indicates that zebra finches, like humans, respond to differences in receiver distance

Acknowledgments

We thank Marc Naguib, Nicolas Mathevon and an anonymous referee for very helpful comments, Roger Mundry for statistical advice and Nigel Mann for the zebra finch drawing used in Fig. 2. H.B. was supported by an Emmy Noether fellowship from the Deutsche Forschungsgemeinschaft (award BR 2309/2-1).

References (45)

  • M. Naguib et al.

    Estimating the distance to a source of sound: mechanisms and adaptations for long-range communication

    Animal Behaviour

    (2001)
  • K.M. Parris

    More bang for your buck: the effect of caller position, habitat and chorus noise on the efficiency of calling in the spring peeper

    Ecological Modelling

    (2002)
  • G.L. Patricelli et al.

    Male satin bowerbirds, Ptilonorhynchus violaceus, adjust their display intensity in response to female startling: an experiment with robotic females

    Animal Behaviour

    (2006)
  • S. de la Torre et al.

    Environmental correlates of vocal communication of wild pygmy marmosets, Cebuella pygmaea

    Animal Behaviour

    (2002)
  • R.H. Wiley et al.

    Adaptations for acoustic communication in birds: sound transmission and signal detection

  • J.W. Bradbury et al.

    Principles of Animal Communication

    (1998)
  • E.A. Brenowitz

    The active space of redwinged blackbird song

    Journal of Comparative Physiology A

    (1982)
  • T.J. Brown et al.

    Sound design for vocalizations: quality in the woods, consistency in the fields

    Condor

    (2000)
  • H. Brumm

    Sound radiation patterns in nightingale (Luscinia megarhynchos) songs

    Journal für Ornithologie

    (2002)
  • H. Brumm

    The impact of environmental noise on song amplitude in a territorial bird

    Journal of Animal Ecology

    (2004)
  • H. Brumm et al.

    Facing the rival: directional singing behaviour in nightingales

    Behaviour

    (2003)
  • C.K. Catchpole et al.

    Bird Song: Biological Themes and Variations

    (1995)
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