Not sure what swan song really sounds like, but it's easier to imagine while sipping this bird-themed cocktail.
Mixing brandy and applejack is quite brilliant. Also the added orange juice brings a sour note to the drink while the tiny amount of grenadine both colors and flavors the drink.
The prop feathers are synthetic by the way, and they have been nowhere near a swan we can assure.
1 oz brandy
1 oz applejack
1 oz fresh orange juice
4 dashes grenadine
Stir with plenty of ice and strain into a coupe.