Seven Swans a-Swimming

Swans are very beautiful, graceful creatures in the water, and bloody violent monsters when they are on a towpath protecting their young. And in England, although that may well be in Britain, I'm not sure, they are themselves under the protection of the Crown, so you're not allowed to defend yourself from them very much, or not to any extent that would result in their death. The RSPB define the conservation status of swans as 'amber' that it to say in danger but not as imminently as species that they consider red, the bittern for example is one of the UK's rarest breeding birds and is classed as red for conservation.

There is a population of swans quite near here in Steveston Harbour, Steveston is part of the City of Richmond and is where a lot of the British ex-pat community live. The swans there have flourished more than the local fishermen and women would have hoped. They are not native and so there are no natural predators to keep the population down. Their faeces are polluting the water and this coupled with the fact that they eat water snails and water plants, both of which help to keep the water clear for fish means that they are changing the environment.
They also get in the way of the fishing boats as they come and go.
It sounds odd that swans should be in a harbour. A harbour we associate with the sea and swans we associate with freshwater. In this case the harbour is on the Fraser River.
Swans will normally live and breed in slow-flowing rivers and canals but will often lay their eggs beside salt and brackish water.

I find it strange that swans in the Northern Hemisphere are predominantly white whilst in the Southern Hemisphere they are predominantly black and white. There is an Australian swan which is entirely black. There is a Norse myth which explains the white swan however. In Asgaard, the home of the gods, there is a well, Urd, whose water is so pure and holy that all who drink from it turn white. The original two swans did just that.

An Irish legend, the Children of Lir, has the standard wicked stepmother turn Lir's children into swans for nine hundred years, but the story doesn't end well, when they finally become human again, they are very old and die quickly, but by then St. Patrick has come and converted Ireland, so they are able to be baptised and buried as Christians. So, depending on your point of view, maybe it does end well.

Lir had four children, and there are two in the Norse Myth. We need one more.

If you read Ovid's 'Metamorphoses' you will see that Jupiter, or Zeus as he was known to the Greeks, was always transforming into creatures so that he could have sex with beautiful but not-strictly-speaking-his-own-wife women. He turned into a swan to thus seduce the Queen of Sparta and so beget Helen of Troy.
Those things never end well.