Physiological and behavioural responses of female mountain white-crowned sparrows to natal- and foreign-dialect songs

The objective of this study was to determine the effect of early song learn ing on physiological and behavioural responses to song in adulthood in fema le mountain white-crowned sparrows (Zonotrichia leucophrys oriantha). Juven ile females were captured before they had dispersed from their natal region . In experiment 1, natal-dialect song, foreign-dialect song, and heterospec ific song were played back to the birds during photostimulation when they w ere 1 year old and physiological responses were measured. The physiological responses (luteinizing hormone and ovarian growth) did not indicate that n atal-dialect song was more stimulating than foreign-dialect song. In experi ment 2, behavioural responses (solicitation displays) to the same songs wer e measured when the birds were 2 years old. The birds showed a clear prefer ence for natal-dialect song, exhibiting more displays to natal-dialect song than to foreign-dialect or heterospecific song. This effect was attenuated in birds that had heard heterospecific or foreign-dialect song when they w ere 1 year old. These results indicate a dissociation between behavioural p references and longer-term physiological responses to song. Although there was a behavioural preference for natal-dialect song, this did not translate into enhanced physiological response as measured here. Moreover, natal dia lect song preferences may be attenuated by adult experience.