Green’s Dictionary of Slang

(Aus.) a sparrow, esp. the (introduced) House Sparrow, Passer domesticus; also attrib.

1900		Eve. Jrnl (Adelaide) 9 Jan. 2/2: Many a [...] person has been hit and a window has been broken by means of a small pebble or jagged piece of lead, intended in the first instance for the bright-plumage parrot or the destructive ‘sproggy’ .
1926		Sunraysia Dly (Mildura, Vic.) 26 Jan. 2/4: ‘If all the boxthorns in Mildura wor desthroyed it wud not lessen the sparrows by wan solitary sproggie’.
1930		Smith’s Wkly (Sydney) 29 Mar. 27/6: The sparrow – common in most parts of Australia – must own more nicknames than any other bird. Here’s eleven of ’em anyhow: – ‘Chirper,’ ‘dadger,’ ‘diggie,’ ‘padjie,’ ‘sprig,’ ‘spriggie,’ ‘spadger,’ ‘spoggie,’ ‘sproggle,’ ‘spidger,’ ‘titter,’ – and what some of the farmers call him at seeding time would fill a book.
1940		Bulletin (Sydney) 24 Apr. 40/3: Its most important advantage, however, is that thousands of sparrows will nest in it, thus providing you and the boys with thousands of sprog eggs.
1941		Bulletin (Sydney) 30 Apr. 16/2: In that same Cabbage Garden, in a spot in fested with boxthorn hedges and herds of sproggies – for the heads of the latter we used to get 1s. a dozen from the local council – we used to wait till the sprogs had settled for the night in the hedges, then sneak up and scare ’em.
1949		Bulletin (Sydney) 19 Jan. 6/1: He could not get beyond his seven-times table [...] but he knew when and where the sproggies nested [...] how to make and use a shanghai, and seven English and one Spanish swearwords.
1953		S.J. Baker Aus. Speaks 104: sproggy, spudgy, or spridgy, a sparrow.
2008		Birding-Aus 26 Nov. 🌐 When I lived in Adelaide (‘75 to ‘93), sparrows were called sproggies, or sprogs, by ordinary (non-birder) folk.