RESPONSES OF MALE TROPICAL MOCKINGBIRDS TO VARIATION IN WITHIN-SONG AND BETWEEN-SONG VERSATILITY

Area of Science:

• Animal behavior
• Bioacoustics
• Ethology

Background:

• Male mockingbirds exhibit large vocal repertoires but sometimes sing repetitively.
• The signal value of repetitive vs. variable singing in territorial defense is not fully understood.

Purpose of the Study:

• To investigate the signal value of vocal versatility in Tropical Mockingbirds (Mimus gilvus).
• To test if repetitive singing signals a stronger threat and elicits a greater aggressive response.

Main Methods:

• Playback experiment simulating male intrusions.
• Measured approach and singing behavior responses.
• Utilized McGregor's (1992) multivariate method and survival analysis for response variables.

Main Results:

• Subjects responded more aggressively to single-note songs than variable songs.
• Higher song switching rates elicited stronger aggressive responses.
• Within-song versatility and switching rate appeared to have independent effects.

Conclusions:

• Vocal versatility in mockingbirds may signal different information depending on its pattern.
• These patterns could mediate territorial conflicts, attract mates, or manage reproductive competition.