From The American Heritage Dictionary of the English Language,5th Edition:

swan song
• farewell or final appearance, action, or work.
• The beautiful legendary song sung only once by a swan in its lifetime, as it is dying.

More of a swan GROWL, really, but Machinist! is calling it quits.
This dark, indomitable swan of a band has soared through the national underground metal scene for more than a decade, feathering its own unique nest while brooding over fellow bands like a Black Mother Hen.
But all adventures must come to an end.
At the waterfront in Brunswick, Georgia, Machinist! ‘ s next to last performance proved that the journey was worth it.
Machinist! has left the building.
Please remain calm.