Green’s Dictionary of Slang

kangarooster n.

[SE kangaroo + sfx -ster]

(Aus.) an amusing or eccentric person (cite 1907 suggests any Australian).

[Aus]Sun. Times (Perth) 16 June 4/7: And Kangaroosters proudly crow / While Brennan’s gyroscoping.
[Aus]Baker Popular Dict. Aus. Sl.