Neighbor-stranger discrimination and individual recognition by voice in the American redstart (Setophaga ruticilla)

This research examined how song is used to transmit information on individual identity in American redstarts (Setophaga ruticilla). Specifically, it attempted to determine whether American redstarts (1) discriminate between neighbors and strangers on the basis of their respective songs, and (2) recognize individuals by their distinctive voice characteristics. I tested the latter by exposing subjects to identical song types sung by different birds. Each subject's behavior was evaluated according to a variety of response variables. In all trials, for all response variables, subjects responded highly but equally to each of the songs played. A post-hoc analysis revealed that the order in which treatment songs were presented affected the birds' responses. For four of five response variables, subjects successfully distinguished between the songs of neighbors and strangers when played the fourth song in the trial. Thus, it would appear that in redstarts this type of discrimination may be observed only after an initial song-exposure period