Bird Song: Steroid Hormones and Plasticity

Abstract

In many species of birds, males sing to court females and to defend territories or nest sites, whereas females sing little, if at all. This behavioural sex difference is paralleled by sexual dimorphisms in neural and peripheral structures involved in song production. In adulthood, singing is generally activated by gonadal steroids, such as testosterone, but the role that these hormones play in the natural development of the structural and functional sex differences is at present an intriguing mystery.

Keywords: zebra finch; oestrogen; canary; aromatase; sex difference

Figure 1.

Sonogram (presented as frequency across time) of a vocal pattern produced by an adult male zebra finch. This song bout consists of an introductory note (i) followed by two repetitions of a series of syllables (a–f).

Figure 2.

Primary brain nuclei involved in song production and song learning. The motor pathway consists of regions connected with orange arrows. The regions connected with blue arrows are involved in the learning process.

Figure 3.

RA in an adult male and adult female zebra finch. The brain region of interest is highlighted with an arrow in each photograph, which depicts brain sections cut at 30‐μm and labelled with the Nissl stain thionin. Magnification of both pictures is the same (30×). The layered structure on the right edge of each photograph is the cerebellum, a brain region involved in the control of movement.

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References

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Further Reading

Arnold AP, Wade J, Grisham W, Jacobs E and Campagnoni AT (1996) Sexual differentiation of the brain in songbirds. Developmental Neuroscience 18: 124–136.

Bottjer SW (1997) Building a bird brain: sculpting neural circuits for a learned behavior. BioEssays 19: 1109–1116.

Harvey S and Etches RJ (1997) Perspectives in Avian Endocrinology. Bristol: Journal of Endocrinology Ltd.

Nelson RJ (1995) An Introduction to Behavioral Endocrinology. Sunderland, MA: Sinauer.

Nordeen EJ and Nordeen KW (1990) Neurogenesis and sensitive periods in avian song learning. Trends in Neurosciences 13: 31–36.

Short RV and Balaban E (1994) The Differences Between the Sexes. Cambridge, UK: Cambridge University Press.

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How to Cite close
Wade, Juli(Sep 2005) Bird Song: Steroid Hormones and Plasticity. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0004042]