Much more importance needs to be given to these foul birds.
I see them a lot in Bris suburbs, and they are extending more and more in to the SE Queensland ecosystem, which is already in a bad state due to excessive tree-clearing and the ozzie dream being developed throughout SEQ. Koalas are in dire straits here, I've not heard one in yrs now (never could spot them in the trees).. but I do have lots of bird, reptile and marsupial diversity, along with the smaller things...

... and more and more mynah's.
I know them well, ..as a kid in NZ they were really dominant, and I recall their calls very well... they are in residence on neighbouring properties, altho the native birds are , with my help, keeping them off my place...They thought that they'd take space at my place once, when I was away for a few weeks... when I got back and saw the dirty birds , I moved them on quick smart..
You CAN keep them off you own place, if you take action..!! they are very smart,
..and if you make it uncomfortable for them they WILL keep away...like..next door. BUGGERS.!!
How??
Interested?/
I have tried to engage some few neighbours in chasing them off, but not enough,.... and as Council literature pointed out , in a pamphlet released here recently, it is a good idea to advise your local council of where you see them, ..rather than chase them off to be someone else's problem. THING with that is, you ring the Council and the operator seems not to understand, for a while, and then can't get anyone as they're all out in the field, etc.
I followed up on the traps with the Council, who eventually were able to tell me, that the plans for the traps were available from another society.. to do with birds..??
Needless to say I continue discouraging them from my own place, and spreading the word to anyone who'll listen..

Do you know how to piss them off from your place? I'll tell you.... assuming your circumstances aren't significantly diff in scale than mine, it should work OK.