I've been studying Black Swans as a hobby since June 2011 in an area of the Gippsland Lakes, (Victoria, Australia).
I have my eye on 10 broods that are mostly habituated with humans and are fairly easy to identify by distinct bill markings and personalities.
IN June 2011, I was on my yacht berthed at Progress Jetty Paynesville and noticed a cygnet get its neck tangled around an abandoned fishing line that was suspended from the jetty.
The father of the cygnet noticed its distress and approached it and began revolving his head in a circular motion. He then, after a loud squawk began to revolve his head/neck in the opposite direction. The cygnet copied the demonstration of the father and freed itself.
I could not believe what I saw as birds are not supposed to be intelligent enough for that kind of behavior.
SO I STARTED ASKING QUESTIONS.
I STILL AM!