This is not about parrots but about songbirds (which parrots are not) but I thought it was VERY interesting -mostly because this is something that I have been exposed to from an early age with canaries and never actually made the connection about it even though I am a hard nose feminist
https://www.medicaldaily.com/are-scient ... rds-443415
PS Actually, in canaryculture, females that sing are VERY appreciated and valuable because they pass their super strong song genes to their offspring.