Meeting Abstract
134.2 Monday, Jan. 7 Whispers of love and war? Inferring the function of low-amplitude song in a songbird REICHARD, D.G.*; RICE, R.J.; SCHULTZ, E.M.; KETTERSON, E.D.; Indiana Univ., Bloomington; Indiana Univ., Bloomington; Univ. of California, Davis; Indiana Univ., Bloomington dgreicha@indiana.edu
Males of many species produce high amplitude long-range songs during the breeding season that often serve a dual function in attracting mates and repelling rivals. In some species, males also produce low-amplitude (whispered) songs during close-proximity interactions that can precede a physical confrontation between males or be paired with visual courtship displays to females. We investigated the function of these songs in the dark-eyed junco (Junco hyemalis), a species of songbird with two distinct low-amplitude songs: (1) soft, long-range song, which does not differ structurally from loud long-range song, and (2) short-range song, which is substantially divergent in structure from long-range song. We presented free-living, male juncos with a live, caged male or female conspecific and quantified the number and type of songs produced to each sex. We also performed a series of playback experiments that tested whether male territorial response differed between high- and low-amplitude songs and whether male response differed according to the fertility status of his mate. Males produced soft and loud long-range song to both male and female conspecifics, but directed short-range song only to females. When confronted with playback of these song types in the absence of a visual stimulus, males responded significantly more aggressively to short-range song than long-range song but did not differ in their response to loud or soft long-range song. When their mates were fertile, males elevated their aggressive response to short-range song but not soft long-range song. Considered together, these results suggest that soft and loud long-range song may serve a similar dual function, while short-range song is a female-directed signal important in courtship.
