Once the swans get used to freedom and find lots of water, they may not want to come back. This is further challenged if others start feeding them and they realize that they don't have to rely on you. Additionally, if the harbor is saltwater or brackish, the swans aren't going to do well as they can't filter salt from the water which can have serious consequences.

Swans can be trained to a certain extent, but they aren't as readily domesticated as duck or goose, so you will have to work with them constantly. Again, they have minds of their own. A swan owns you, not vice versa. If your patio is not enclosed, the swans are open to predation at night, domestic dogs, cats and wild predators can and will find them.

California like other states erroneously label Mute Swans as an invasive species which could not be further from the truth. However, because of this mislabeling, you may need to have a permit to possess them,. The Regal Swan