Green’s Dictionary of Slang

1. a duck, a goose.

1785		Grose Classical Dict. of the Vulgar Tongue n.p.: Lastly, I will cleave to my doxy wap stiffly, and will bring her duds, marjery praters, goblers, grunting cheats, or tibs of the buttery, or any thing else I can come at, as winnings for her weppings.
1879		letter 15 Apr. in T. Hughes Gone To Texas (1884) 84: His geese come and stay all day sometimes, and one of his gobblers has apparently taken up his abode here permanently.

2. (Aus.) a Turkish soldier [play on SE gobbler, turkey].

1915

C.E.W. Bean Anzac Book 32/2: Yes; some d–––d gobblers thought they would catch our mob nappin’ but missed the bus, and some of ’em are still runnin’ yellin’ to Aller to stick to ’em.

3. a Morroccan policeman.

1968

A. Burgess Enderby Outside in Complete Enderby (2002) 303: Gobblers watching at the airport and on the shemmy.