Have you seen an Indian Myna (bird) recently? These birds are not native to Australia and aggressively compete with native birds and animals that need tree hollows to nest in. They are also scavengers around eating areas and create a lot of noise from communal nesting.
Mynas also increase the fire risk in ceilings if they get into your roof due to the dry grassy material they bring in for their nests. If that is not bad enough they carry mites so you really don’t want them in your ceiling.This gives you an idea why it is better to not encourage them into your area. They are quite common in larger cities.
To get a better idea on where they are locally and hopefully deal with isolated populations, it would be handy to know where you have spotted them. The easiest way to do this is to go onto mynascan and map the location. You will need to register. It is an easy process and this mapping program is also used to map other pest such as rabbits and foxes. You may like to add any sighting of these pests as well.