Table 2.

Results of published studies on zebra finch song structure and song performance as an indicator of early developmental stress

Study	Method of stress induction	Phrase duration	Total number of syllables	Total number of different syllables types	Percentage of copied syllables	Percentage of copied syllables types	Learning accuracy	Song amplitude
Spencer et al. 2003	Food restriction	Decreased	Reduced	No effect
Gil et al. 2006	Brood size manipulation	No effect	No effect	No effect			No effecta
Zann and Cash 2008	Food restriction	Increased	No effect	No effect			No effectb
Holveck et al. 2008	Brood size manipulation	No effect	No effect	No effect	No effect	No effect	Decreasedc
This study	Food restriction	No effect	No effect	No effect	No effect	No effect	Decreasedb	No effect

Cells with no entries indicate that the respective trait has not been investigated

^aBased on visual comparisons of tutor and tutee songs

^bBased on spectral parameter analysis with Sound Analysis Pro software

^cBased on spectral parameter analysis with Luscinia software