Windsurfing swans: An overlooked phenomenon

In the latest issue of The Wilson Journal of Ornithology Olle Terenius describes how he on three occasions has observed Mute swans windsurfing. That is travelling at high speed several hundred meters on the water surface with the help of the wind. Windsurfing swans have been sighted in 1999, 2014 and 2015 at three different locations in Sweden.

"This leads me to believe that the phenomenon is not confined to a particular place or a few birds. I hope this article makes more people become aware of windsurfing Mute swans and that we get a better picture of how widespread the behavior is when other people start reporting this phenomenon," says Olle Terenius.

The experts, with deep insights into the literature of Mute swans, who reviewed the article and the supplemented film, were unaware that the Mute swans can move in this way.

"I think the reason that this is missing in the literature is that ornithologists who are out in the field only quickly note that they see a Mute swan and write it down on the list of bird observations, while the general public has observed windsurfing swans thinking that this is already a well-known phenomenon," says Olle Terenius.

The Mute Swan, weighing around 10-12 kg (22-26 lbs), is the heaviest bird that can fly and needs a long distance to take off. Quickly moving downwind a few hundred meters is an energy-consuming activity if they are to fly. When they instead windsurf, the Mute swan can start moving immediately; they move quickly, approximately two swan lengths (1.3 meters) per second.

"Probably the behavior is a way to save energy," says Olle Terenius. "If they had paddled with their feet in the same speed, it would have required about the same effort as a person playing squash."