Meeting Abstract
We conducted a field experiment to study the male-male aggressive function of song and singing behavior in the Bachman’s sparrow. An aggressive signal is one that is 1) associated with an aggressive context, 2) predicts attack or escalation towards attack, and 3) is responded to by receivers appropriately, i.e., with aggressive escalation or retreat. We are testing these predictions for three types of song produced by territorial male Bachman’s sparrows in response to a threat by a rival male: ‘primary song,’ low amplitude ‘whisper song,’ and ‘excited song’. During the breeding season (May-June) we performed simulated territorial intrusions (STIs), using song playback and a model of a male Bachman’s sparrow, on the territories of 30 males at Johnathan Dickinson State Park in south Florida. We are quantifying the subject males’ vocal and other behavioral responses with the aim of determining which vocal behaviors, if any, are reliable threat signals, and if particular sequences of signals predict escalation versus de-escalation. We are analyzing movement, proximity and attack behaviors to quantify each male’s aggressiveness, and will relate aggressiveness to song type use and other aspects of singing behavior (song rate, song type switching rate). Our results will contribute to a better understanding of the social behavior and communication system of this enigmatic species.
