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 learning on physiological and behavioural responses to song in adulthood in female mountain white-crowned sparrows (Zonotrichia leucophrys oriantha). Juvenile females were captured before they had dispersed from their natal region. In experiment 1, natal-dialect song, foreign-dialect song, and heterospecific song were played back to the birds during photostimulation when they were 1 year old and physiological responses were measured. The physiological responses (luteinizing hormone and ovarian growth) did not indicate that natal-dialect song was more stimulating than foreign-dialect song. In experiment 2, behavioural responses (solicitation displays) to the same songs were measured when the birds were 2 years old. The birds showed a clear preference 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 were 1 year old. These results indicate a dissociation between behavioural preferences 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 dialect song preferences may be attenuated by adult experience.