We watched this pair of Mute Swans doing many maneuvers and this was one of them. I have never seen birds in this position before. They appear to be looking into each other’s eyes. Their upper body resembles a heart.
The male is on the left and has a thicker neck. During breeding season, the black knob at the base of the bill of the male (cob) swells. The female (pen) on the right is slightly smaller and has a smaller knob. I have never paid attention to Mute Swans to be able to identify the male from the female, but noticed the difference in this photo, so I looked up the differences online.