Cygnicide

[A]s my eye wandered carelessly across the face of the water, it was electrified by the sight of a splendid black swan, (the only one I had ever seen wild,) sailing out of the rushes on the margin of the lagoon, about fifty yards from my station. […] Perhaps I might as well have galloped at once for my gun, for it is vain to deny that I had already committed cycnicide in my heart.

Source: wiktionary

The same reluctance to kill, or when killed to eat a swan, prevails in parts, if not in the whole of Connacht. I knew one man who shot a swan, and his father would not allow it to be eaten. Another man assured me he had once shot one, and if he lived for a thousand years he never would do so again. I have never tried the experiment myself, but if it be true that / —facinus qui cogitat ullum / Facti crimen habet— / I should be most certainly amenable to all the supernatural penalties of cygnicide; but though I have fulfilled the Highland saying, seilgire thu nuair mharbhas tu gé corr agus crotach, I have hitherto found the eala one too many for me!

Source: wiktionary

And then we recollected the tradition of our youth that the swan, silent in life, supplies the music at his own funeral. “This bird,” says Erman in his “Travels in Siberia,” “pours forth its last breath in notes most clear and loud”; and who that has been a boy or a girl—and which of us has not, alas!—has not recited: “‘What is that, mother?’ ‘The swan, my love, … death darkens his eye and unplumes his wings’”? History does not record whether Dr. G. Donne died after composing those best lines of his: but little he thought of the temptation to cygnicide involved therein for future generations. Three boys in Cheshire were haled before a magistrate to answer for the felony of slaying a swan in a baronial moat. They “wanted to hear it sing”!

Source: wiktionary

One of the black swans of Stow Lake was found dead Wednesday near the edge of the lake. A prowling coyote was suspected of the cygnicide and a trap was set for him, the carcass of the swan, filled with poison, being set in the snare.

Source: wiktionary