Swans have long been a symbol of monogamous love, but it seems there are love rats aplenty in the matrimonial nest.
Research into the sex life of black swans shows infidelity is rife among the species famed for mating for life.
DNA paternity testing undertaken by the University of Melbourne's zoology department has revealed about one in every six baby swans is a love child spawned by secret matings.
The university's Dr Raoul Mulder said the findings were unusual because male swans were typically very protective of their female companions.
Now the university is out to catch them in the act.
Researchers will use a state-of-the-art tracking devices to monitor the mating habits of black swans at Melbourne's Albert Park Lake.
The technology will also track the males' philandering - it is the equivalent of a notch on the bed post.
Dr Mulder said the often secretive mating habits of birds had proven difficult or impossible to monitor in the wild.
But by tagging male swans with a tiny microchip and females with a decoder, researchers will record the birds' most intimate moments.
"When a male and female copulate, the female's decoder unit detects the microchip implanted in the male's tail feathers, registering the male's identity, as well as the time of copulation," Dr Mulder said.
"All mating events are logged onto the decoder unit, so that a complete record of her mating behaviour over several weeks can be downloaded when the swan is recaptured."
The results will provide the first snapshot of a swan's true bedroom behaviour and could dispel the myth that swans have one life-long partner.
"Our research hopes to provide new material for nature documentaries and reveal to the world the true sexual nature of these iconic birds," Dr Mulder said.
Tagging of up to 150 swans started in May 2006 and is expected to be completed next month, in time for the Spring breeding season.
The miniature detectors weigh 150 grams and are worn by the females like a small backpack.
Dr Mulder said the study targeted black swans because they were large enough to wear the tracking device and were more common than their introduced white cousins.
In mythology, swans also represent "purity and fidelity," a perception Dr Mulder is keen to dispel.
He said researchers had known for some time that swans were not as monogamous as they appeared and paternity testing proved that.
But how the females managed to escape the clutches of their partners for an extra-marital interlude, and how often, remained a mystery.
"It's the first time that we're actually going to be able to use the technology in any bird to get the complete record of what the females' behaviour is," Dr Mulder said.
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