Green’s Dictionary of Slang

a convict.

1984

Partridge DSUE (8th edn) 1190/2: ca. 1815–90.

(Aus.) a rough blanket, used by vagrants and tramps and made of a sack or bag.

1943

Baker Popular Dict. Aus. Sl. (2nd edn).

(US) an Australian who joined the Californian Gold Rush of 1849; thus a former Aus. convict who pursued his villainies in San Francisco; also attrib.

1853		Life in Boston & N.Y. (Boston, MA) 1 Oct. n.p.: He has been challenged by a Sydney duck, named Clare.
1854		Soulé, Gihon & Nisbet Annals of S.F. 634: A few ‘swells’ and sharpers of the ‘Sydney-cove’ school.
1877		Newcastle Wkly Courant 6 July 6/3: ‘You appear to be talking of some gold dust’ [...] ‘Only what I’ve saved,’ rejoins the Sydney duck.
1879		W.J. Barry Up and Down 114: They had still a very great ‘down,’ I noticed, on the Sydney people or the ‘Sydney Ducks.’.
1880		‘Edward Howe’ Roughing It in Van Diemen’s Land 52: Here was, in Californian slang, a ‘Sydney duck,’ far better worth bagging than the Tasmanian ones he had been trying for.
1904		Sydney Sportsman (Surry Hills, NSW) 2 Mar. 8/5: I have no doubt he mingled among the ‘Sydney ducks’ on the Pacific Slope, and if ‘blow’ and ‘bounce’ could do it ho would earn a living.
1920		Illus. Buffalo Morn. Exp. (NY) 4 Apr. 27/1: The Sydney Duck had suspended the stolen lump in a fiber net.
1933		(con. mid-19C) H. Asbury Barbary Coast (2002) 50: The villainous inhabitants of Sydney-Town were popularly called Sydney Ducks or Sydney Coves, but more often the former. It was a common saying in early San Francisco, whenever a particularly atrocious crime was committed, that ‘the Sydney Ducks are cackling in the pond.’.
1948		(ref. to 1850s) Sun. Times (Perth) 25 Apr. 35/3: In the 1850s, shiploads of tough Australians sailed to California [...] Californians dubbed them the Sydney ducks.
1968		(con. mid-19C) S. Longstreet Wilder Shore 61: Felons by their very look – some branded on cheek or thumb. They were called Sydney Coves or Sydney Ducks.

(Aus.) phr. used to express a highly pessimistic assessment of one’s chances.

1983		J. Byrell (con. 1959) Up the Cross 10: ‘If they were rafflin’ Sydney I’d end up winnin’ a Jap dunny’.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 151: ‘Fair dinkum, if they were raffling Sydney I’d win a friggin’ Jap shithouse!’ [ibid.] 168: ‘With the sorta luck I’m lumbered with today, if they were raffling Sydney I’d win the Jap shithouse’.

(Aus.) all or nothing.

1915		Drew & Evans Grifter 105: ‘Dig in while your luck’s in. Sydney or the bush’.
1920		Western Argus (Kalgoorlie, WA) 15 June 1/4: One of the most picturesque exclamations of the Australian soldier [...] ‘Well, Sydney or the bush,’ when a Digger risks all on the spin of a coin.
1924		G.H. Lawson Dict. of Aus. Words And Terms 🌐 SYDNEY OR THE BUSH—All or nothing.
1930		E. Shann Economic Hist. Aus. 365: ‘Sydney or the bush!’ cries the Australian when he gambles against odds [OED].
1945		Baker Aus. Lang. 76: Sydney or the bush, a phrase indicating the choice of a final alternative.
1970		(con. 1941) R. Beilby No Medals for Aphrodite 34: ‘Here we go,’ Turk murmured grimly, climbing in behind the wheel. ‘It’s Sydney or the bush! Keep your fingers crossed.’.