Unfortunately the time will come when the long grass will need to be cut. That day was yesterday. We only cut behind the house and left the front for the birds. When I got up this morning , there was utter silence. No birds, no Parrots or any other birds. Not even my Wrens, I fear they might have decided to move to the bush behind us. There are still a lot of long weeds left. I hope they will come back.
Now there's an interesting conundrum, Araminta. I would have thought that at least the birds would be on the long grass at the front of your house, especially since it's probably producing seed &/or maybe insects are on the grass flowers. Is it possible the noise of the mower has frightened off the birds for a while? What happened when you mowed last year?
By the way, I've found in several areas a native herb Tom Thumb Dichondra repens smothered by weeds. I've mowed right over the top of the Tom Thumb in some places. In other places the weeds have been so thick that it's been safe to spray over the weeds with no harm done to the Tom Thumb. I suspect other native herbs may be in similar circumstances at this time of year. I'm not sure what role Tom Thumb plays in relation to birds but I suspect the flowers attract insects which, in turn, attract superb fairy wrens & yellow-rumped thornbills.