Song learning in the song sparrow (Melospiza melodia): ecological and social factors
Nordby, Jennifer Cully
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During song learning, songbirds are exposed to many more songs then they keep for their final song repertoire and little is known about how or why a bird selects the particular songs he sings as an adult. These studies examine the social and ecological factors that influence song learning and repertoire development in a sedentary Washington population of song sparrows ( Melospiza melodia). In the first study, I examined the song repertoires of an entire cohort of males and compared them to those of potential song tutors. I found that a young male (1) learns whole song types, (2) learns songs from multiple tutors who were neighbors in his first year, (3) establishes a territory among or near these tutors, and (4) learns more songs from tutors who survive the winter. In the second study, I attempted to replicate in the laboratory the key variables of the natural song learning environment by exposing hand-reared male song sparrows to live adult tutors. Results from this experiment confirmed findings from the field study. In addition, this experiment showed that (1) interactions with a close neighbor after the natal summer affect song learning and (2) males preferentially learn songs that are shared among their tutors and other males in their same age cohort. In the third study, I examined whether song sparrows were capable of acquiring new songs after their presumed sensitive period for song memorization (30--90 days of age) by exposing them to new tutors after their natal summer. Eight of 12 subjects learned songs from tutors they only heard after 140 days of age, and six subjects learned most of their songs from a late tutor. Thus, song sparrows are capable of acquiring many songs de novo in late fall, and may be capable of acquiring songs even later. Taken together, these studies demonstrate that young male song sparrows have a song learning strategy that provides them with a repertoire of song types they will share with their neighbors in their first-breeding season and that social interactions after the natal summer are crucial to song repertoire development.
- Psychology