We examined recognition of individual neighbors in hooded warblers
(Wilsonia citrina) and Kentucky warblers (Oporornis
formosus) by comparing responses to playbacks of neighbors' songs from
appropriate and inappropriate boundaries of the subjects' territories.
Kentucky warblers, which sing one song type each, responded more strongly
to the songs of neighbors broadcast from incorrect than from correct
boundaries. Hooded warblers use their repertoires of three to nine song
types in two distinct modes of singing: repeat mode involves
repeated presentation of one song type; mixed mode involves presentation
of two or more song types in irregular sequence. Playbacks of neighbors'
mixed-mode songs from appropriate and inappropriate boundaries indicated
capabilities of individual recognition similar to those reported
previously for repeat-mode songs (Godard 1991) and to those of Kentucky
Repertoires of moderate size, therefore, have no pronounced influence on
eventual recognition of individual neighbors in hooded warblers.