Secret Sex Lives Of Swans Under Scrutiny In New Study

“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,” says Dr Raoul Mulder from the University of Melbourne’s Department of Zoology.

Previous DNA paternity analysis has revealed that about one in six baby swans are ‘illegitimate’, resulting from secretive matings between a female and a male other than her own partner.

“What is unusual about these findings is that male swans are typically very protective of their female companions. How then can a female be promiscuous in this relationship? Is she sneaking off in the middle of the night to meet other swans? In addition, the male is also seeking bonus copulation with other females,” says Dr Mulder.

Dr Mulder says the often secretive mating habits of birds have proven difficult or impossible to monitor in the wild. He says the project’s innovative technology will, for the first time, provide researchers with a way of monitoring the swans’ secretive sexual behaviour.

A research team led by Dr Mulder will be capturing and tagging the swans that live around the lake as part of a long-term study.

On top of the standard procedures for monitoring the birds, each of the males will have a tiny microchip attached to one of its tail feathers.

Dr Mulder explains that during the breeding season, the females will be temporarily fitted with a miniature state-of-the-art electronic tracking device, or ‘decoder. He says the decoder recognises individual microchips similar to how e-tags operate.

“The devices look similar to small backpacks and are placed on the bird’s lower back,” he says

“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.”

“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 of the study will be presented for scientific publication. “Our research hopes to provide new material for nature documentaries and reveal to the world, the true sexual nature of these iconic birds.”

The study at Albert Park Lake is funded by a grant from the Australian Research Council, with permission from Parks Victoria, the Department of Sustainability and Environment, the Australian Bird and Bat Banding Scheme and the University of Melbourne’s Animal Experimentation Ethics Committee.