This morning I noticed two mute swans acting rather strangely.

The swan infront appeared to be being chased by a swan behind it, the latter of which had it's neck down on it's back, and wings fluffed and held up. When the swan at the back caught up, the forward swan would fly for a couple of metres, then land, swim, until the other caught up again.

I'm really confused as to why they would do this! This was in England, so I don't think it's mating season. Or is it territorial?