Female Song in Galápagos Warblers Challenges Assumptions About Birdsong

For decades, birdsong research has largely focused on males, overlooking the vocal contributions of females. A new study by researchers from the University of Vienna and Anglia Ruskin University shows that female Galápagos yellow warblers (Setophaga petechia aureola) sing frequently—but not for the reasons males do. Published in Animal Behaviour, the research indicates that female song is not linked to aggression or territorial defence, challenging long-standing assumptions about the function of birdsong.

The team conducted playback experiments simulating territorial intrusions on Floreana Island in the Galápagos. They found that while female warblers sang during aggressive encounters, their singing was not associated with territorial defence or competition with other females. Instead, female songs were mostly part of duets with male partners, suggesting a primary role in pair communication.

“Male song was closely linked to aggression during territorial encounters. In females, however, singing and aggression appeared to be unrelated behaviours,” said Alper Yelimlieş, first author from the Department of Behavioral and Cognitive Biology, University of Vienna. “Most female songs occurred as duets with their paired mates, highlighting a communication role within the pair rather than territorial signalling.”

The findings contribute to growing evidence that female song is widespread, particularly among tropical songbirds, and emphasizes the importance of including females in studies of avian vocal communication. By documenting this behaviour in Galápagos yellow warblers, the study challenges traditional biases in behavioural biology and provides new insights into the evolution of birdsong.

Key Findings:

• Female warblers sing primarily during the non-breeding season.

• Singing mostly occurs as duets with male partners.

• Female song is unrelated to aggression or territorial defence.

• The research highlights the need to study both sexes to fully understand birdsong evolution.