Researches study the sex lives of black swans

Swans have long been viewed as a symbol of fidelity and everlasting love. But in fact they are cheating philanderers who regularly flee the nest for extramarital sex, Australian researchers have revealed.

"Swans have long been renowned as symbols of lifelong fidelity and devotion, but our recent work has shown that infidelity is rife among black swans," said Raoul Mulder from the University of Melbourne's zoology department.

He and colleagues tested the DNA of many cygnets and found that one in six is the product of an illicit encounter. Researchers now wonder how females manage to slip away from their over-protective partners, to mate on the side. To find out they are now attaching tracking devices on swans' tail feathers.

Up to 60 male swans at Melbourne's Albert Park Lake are being fitted with a tiny microchip. The females on the other hand are being fitted with a miniature tracking device, known as a decoder.

"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," Mulder said. "All mating events are logged onto the decoder unit, so that a complete record of her mating behavior over several weeks can be downloaded when the swan is recaptured."

Mulder said the study targeted black swans because they were large enough to wear the tracking device and were more common in Australia than their white cousins.

Mulder noted that "there are risks associated with mating with other birds so there must be some evolutionary benefits." He told AFP that they don't rule out the possibility that swans have a very sophisticated mating behavior.

Scientists are trying to see what are the strategies adopted by the females in their choice of mates and how they change their partner for another one with superior genes. Such strategies should ensure the maximum fitness of their offspring.