As I watched black swans shrouded in the mists of a Bridgewater Jerry on the upper Derwent, I could see why the beautiful and graceful birds have always formed a powerful, almost spiritual image through the haze of human history.
Swans are symbols of love, devotion and fidelity. There are plenty of fairy tales about swans mating for life, and even grieving for years if their beloved partner dies.
Scientists in Melbourne have now confirmed it’s one myth that has some truth to it.
Since 2006, Melbourne University academics have been studying the black swans at Albert Park in the city and their findings have produced irresistible parallels with the life of humans.
Not only do many swans pair for life, “marriage” can be strengthened by time away from each other and synchronised behaviour is also vital – eat, fly, preen and swim; they do it at the same time.
What started as a study on the effects of drought quickly evolved to analysing the sex lives of swans. In the nearly two decades since, between 1500 and 2000 swans have been tagged and observed as part of the study. Early on in the research, the university confirmed that swans were indeed monogamous in the wild – but not all the time. Some pairings could be life-long, but some only lasted months.
“Divorce is not uncommon,” says Raoul Mulder from Melbourne University’s school of biosciences. “About 10 per cent of swan pairs don’t last.”
A DNA study from Albert Park found cheating was not uncommon either. About one in six cygnets on the lake were fathered by a male outside the pair bond.
During the 18-year study, the university has used collars with unique number and letter sequences to identify the swans. It has also led to Professor Mulder getting occasional calls about random swans flying dozens of kilometres away from Albert Park.
The data – which is still being gathered – found 40 per cent of pairs spent time apart, with breaks going for about two to three months and some flying up to 37 km from their partners.
Half of those that took a break broke up permanently, while the other half stayed together, apparently as strong as before.
The scientists looked at whether the pairs that had been together longer had more separation, and they didn’t find that was the case. And established pairs that separated didn’t have more offspring. So the researchers say they need to collect more data and figure out why these breaks occur.
Unlike nature writers such as myself, scientists are traditionally wary of anthropomorphism – assigning human characteristics to birds – but there is clearly a parallel in the life of two species, even if they are separated by millions of years of evolution. Partnerships, whether they be swan or human, are more complicated than they appear on the surface.