Yeasterday - May 22 - I saw two Mute Swans in close contact. During the foreplay the biting was not very aggressive and after a couple of minutes it could look like a mating. But after 15 seconds the first swan had forced the second swan's head under the water for the first time and the first swan tried for almost 2 minutes to keep the second swan's head under the surface. Hereafter the second swan escaped but got caught again 2 times. It escaped definitely after approximately 7 minutes.

The hole battle was followed with high interest by a third swan and after the battle the first and third swan unified in an idyllic way.

So what I saw was not a mating but a serious territorial fight between 2 males and an attempted murder with a female swan as excited spectator.

Pictures are on the link below.