‘Cheating’ birds change their tune — and females can tell

Recent research published in Ethology reveals that female pied flycatchers can detect if a male bird is already in a relationship by listening to his song. Scientists discovered that male pied flycatchers adjust their tunes after mating and moving to another territory to court a second female. These songs become shorter and feature less repetition of syllables.

Researchers played songs from male birds who had partners or recently mated to female pied flycatchers, and the females responded differently to songs from birds who had already paired up. This behavior may be due to the male's reduced time investment in raising chicks after mating, as well as the potential for reduced detection by the first mate when the bird engages in infidelity.

While the study does not confirm whether females consciously recognize their mate's infidelity, it suggests that females can pick up on subtle song differences associated with a male's mating status.