Males of the magnificent frigatebird (Fregata magnificens) have a large red throat pouch. They visually display this pouch and use it to make a drumming sound when seeking mates.
Usage
data(FrigateB)
Arguments
Format
A data frame with 18 observations on the following two variables.
Vol
Volume (\(cm^3)\).
Frq
Frequency (\(Hz\)).
Details
Madsen et al. (2004) wanted to know whether females, who presumably choose mates based on their pouch size, could use the pitch of the drumming sound as an indicator of pouch size. The authors estimated the volume of the pouch and the fundamental frequency of the drumming sound in 18 males.