Gardening

I'd give this swan a wide berth, he looks quite deranged.
He and his Mrs have just one cygnet, which doesn't seem to have left him with enough to do. So while she was looking after Junior, he was energetically and systematically demolishing a large clump of reeds in the middle of the pond - uprooting some, breaking others off, chucking them over his shoulder and then just leaving them floating. This is just a small part of it.
What was he up to?