The Neural Encoding of Heterospecific Vocalizations in the Avian Pallium: An Ethological Approach

• Author / Creator

  Avey, Marc

• Songbirds (order Passeriformes, suborder Oscines) have captured the attention of scientists and non-scientists alike with their vocal signals. The black-capped chickadee (genus Poecile) uses its namesake call, chick-a-dee, to convey a variety of information. In Chapter 2 and 3, I examine the relationship between season and diurnal cycle and the production of three vocalizations of black-capped chickadees. In the natural habitat chick-a-dee call production was highest in autumn and winter generally at the meridian. Fee-bee song production increased once in the winter and once in the spring, and occurred almost exclusively at dawn. Gargle production did not differ significantly by season but most occurred during the meridian (Chapter 2). In the laboratory, the patterns of production were in general agreement with the patterns in the natural habitat (Chapter 3). In Chapter 4, I examined what role the phylogenetic relatedness of a heterospecific individual had on neural activity, measured via an immediate early gene, in the auditory brain areas. Using natural calls I found that there was no difference in the amount of neural response from closely individuals but there was less response from a distantly related individual. To further examine this I used calls that were more similar in their bioacoustic structures. With these calls I found no difference in the amount of neural activity regardless of phylogenetic proximity. In Chapter 5, I used mobbing calls to explore whether ‘degree of threat’ is encoded in the auditory processing brain areas. Degree of threat was indicated by the amount of neural activity with high threat mobbing calls and high threat predator calls generating the most activity followed by low threat mobbing calls and low threat predator calls. Thus the ‘degree of threat’ was related to the amount of neural activity and within a threat level there was difference in the amount of activity regardless of the source of the threat. Finally, hand-reared birds had greater neural activity in response to mobbing calls which they had experience with than predator calls which they had no experience with. This result suggests that threat is a learned response and that the neural response is affected.

• Subjects / Keywords

  • Songbirds
  • Chickadee
  • Diurnal
  • ZENK
  • Seasonal
  • Bioacoustics
  • Perception
  • Heterospecific
  • Immediate early gene
  • Communications

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3HQ48

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.