A silent ballet for mute swans at Humber Bay
Finding myself with a few spare hours on a recent chilly but sunny afternoon, I grabbed the opportunity to head out and let fate decide what encounter I might have with Mother Nature. Humber Bay seemed like a good place to start my adventure: there is always a multitude of ducks in its protected waters, and it is the home of a butterfly habitat. Perhaps I might catch a glimpse of an early flyer?
Shortly after I arrived at the bay, however, it was neither ducks nor butterflies that captured my gaze. It was a pair of mute swans ( Cygnus olor) behaving peculiarly.
The swans, which I took to be a mature male and a female, were turning on the spot in small, tight circles. First this way, then the other. As I watched, I realized that their turns — sometimes clockwise, sometimes counterclockwise — were completely synchronized.
On the water, the slow, deliberate rotations created a swan ballet that looked as if it had been choreographed by Terpsichore herself. In more than a decade of passionate swan watching, I had never seen behaviour like this, so I grabbed the point-and-shoot camera from my pocket to record it.
With the graceful, co-ordinated movements of the two birds, I thought I was witnessing some as- pect of the swan mating dance I was unfamiliar with. But something wasn’t quite right. Both swans were in the busking posture, with their wings raised and their necks drawn down low over their backs. This is the position swans adopt to confront a threat: it protects their long, vulnerable necks and gives them maximum forward propulsion should there be a confrontation. I watched, mesmerized, trying to interpret what I was seeing, when suddenly, the peaceful scene shattered. The mature male swan lunged at the swan he’d been circling with and, in a furious flap of feathers, the two began fighting. Swan fights are serious matters that can lead to the loser’s death by drowning; they bite at each other’s necks, and use their powerful wings to get up on their opponent’s back and try to submerge them. At one point, the attacking swan was held underwater for some seconds by his opponent, and I feared the worst. But he eventually surfaced, lunging anew at the other swan. More feathers flew from the swans’ powerful wing beats and suddenly the fight ended as swiftly as it had begun, with the attacking male emerging victorious. During the battle, another pair of swans got into it, too, before settling their differences and swimming away. Back at home, I did some research to understand what I had wit- nessed. Far from being part of the mating dance between a male and female, as I had supposed, the strange circling behaviour turned out to be two males — a mature male and a younger challenger — working out a kind of cygnine truce.
In 1984, biologist Hans Lind at the University of Copenhagen described the “rotation display” of two male swans in the aggressive busking posture as a kind of nonviolent method of establishing their respective territories. He suggested the turning display takes place at the territorial boundary line and conveys the boundary to potential intruders, as well as to the family members of both males.
Apparently the peace pact being worked out by the two swans I was watching at Humber Bay didn’t quite stick, devolving as it did to a furious fight.
Who knows, though. In the end, not one of the four fighting swans appeared to be seriously injured, and peace had been restored — for a while, anyway — to the bay. mbream@thestar.ca