Females don't always sing in response to male song, but when they do, they sing to males with higher pitched songs
A. N. G. Kirschel, Z. Zanti, Z. T. Harlow, E. E. Vallejo, M. L. Cody, C. E. Taylor
The study shows female birds sing in response to higher-pitched male songs, suggesting they assess male size and threat level during territory defense.
bioRxiv · May 5, 2020Animal Behavior & Cognition