Voyeuristic female peacocks like to listen in on males having sex, ornithologists have found.
Biologsit Jessica Yorzinski was studying why male peacocks sing to prospective partners just before copulation.
The peacock courtship dance - the "hoot-dash display" - involves the male running towards his partner and emitting a single squawk before mating.
Her study, which will appear in the January edition of the journal Behaviour, asked why males do this when there are such clear drawbacks to it.
She said: "Peacocks have a number of different courtship calls, but this is the only one specifically associated with the moment before copulation, a time when the female is finally right in front of the male. It's called the hoot-dash display.
"By that point she's already right there, checking him out. You'd think that he might not need another signal at such a late stage in the courtship process."
Peacocks are a tasty snack for jackals, tigers and hawks in their native home of south Asia. Why they would advertise their whereabouts to predators when they have already got their mate has baffled scientists for some time.
If he's good enough for one girl...
"In a sense, they're advertising that they're distracted and vulnerable. It would be wise for a predator to capitalise on that."
Yorzinski recorded the hoot-dash display and the loud carryings-on of male peacocks during sex.
She then played these back to free-ranging lady peacocks and videoed their reaction. She also had silent control days.
Findings showed that on the sex days, the female peacocks were drawn to the sound of a male mid-conquest. They spent more time near the speakers on the sex days than on the silent ones.
To ensure the peacocks were not just drawn to noise in general, she played crow caws. However, the peacocks were not interested in these sounds.
It is thought the male advertising that he has got a mate could help him attract more lady friends.
"It's like someone's already vouched for him. If he's good enough for one girl, then he might be good enough for another girl, too," Yorzinski said.