The Urban Dictionary pretty much nails it: Galah: An “Old Australian” word; an derogatory term that means a “loud-mouthed idiot.” Named specifically for the galah, a native Australian bird that makes a distinctive (and quite funny-sounding) call.”Oh, Scotty, ya bloody galah! What are you ON ABOUT?!”
It is, fortunately, now an outdated Australian insult and these beautiful parrots are mostly spared being put in the same class as politicians and various other “fools, clowns, doofuses, sapheads, dickheads, dills and nongs”. Similarly the spangled drongo is also now spared such insult, although 40 years ago drongo was a common label for a dill…etc.
Galahs (Eolophus roseicapillus) are often seen in large flocks inland, especially in grain-growing country. The galah above and her/his mate were augmenting their diet with some weedy greens from the Nightcliff foreshore.