Scrubwren maybe

Hi Steve

I am going to offer a couple of strange suggestions - depending upon your assessment of the size of the bird.
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The plainest bird I ever handled (as a young apprentice bird-bander) was a Reed Warbler. In the hand we simply could not work out what it was (some kind of Honeyeater?) Then when it was set free - it flew to a bush and called - and was immediately recognisable as a Reed Warbler. So, if it was roughly the size of a Yellow-faced Honeyeater (or Reed Warbler) that would be a suggestion.
Two links to try:
http://photogallery.canberrabirds.org.au/images/Reed-Warbler_Clamorous2_HanschL.jpg
http://photogallery.canberrabirds.org.au/images/Reed-Warbler_Clamorous2_Dabb.jpg
Reed Warblers do not always sit in reeds, but nearly always are within 50 metres of wet areas at least (as you probably realise). I know it sounds like an unlikely option, but if you check those links, you will see what I mean about their "plainness", ie, lack of distinguishing features (other than habitat and call).
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Second option is more likely, I think.
I am going for a juvenile Superb Fairy Wren. Females have reddish feathers around the eyes, but juveniles do not have that straight away. Fledglings have the yellow gape (which your bird does not) but in most other respects, it looks right for an immature Wren, with a half-grown tail.
Suggest you look at the Canberra Ornithologists Group Photo Gallery for the SFW. They have many photos of adult females (which it clearly is not) and some of juveniles and fledglings - which it might be. Have a browse through this group of images.
http://photogallery.canberrabirds.org.au/fairy-wren.htm
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Best of luck. It is a hard one, without seeing it in the flesh - without other objects around to judge size, etc, or to hear calls.
Cheers
Denis

hi Denis (and steve)
Thats because I only typed 6 words :-)
Your suggestion of a wren crossed my mind, the female of the Red-backed is very plain, but the 'jizz' from that photo (and I know it is difficult to tell from a picture) seems to point to a RW.

Hi Ed
I like the match of the angle of the head, and the eye, and the largish beak.
Yours is a nice photo by the way.
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I await Steve's comments with interest.
Reed Warblers are not always as brownish as yours - sometimes duller. I deliberately avoided linking to one of Geoffrey Dabb's image of the RW for that reason - from the COG Gallery.
He had a really brown one, like yours.
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RWs do tend to have a slight crest, (as your bird does) but that might be seasonal, or even hormonal (Males???). Not sure.
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Cheers
Denis

Hi Steve
When you came back and said it was near the University Swamp, it was all over bar the shouting in my mind.
Game set and match.
Other cliches, as you like.
This close-up shot of the head of the RW was pretty convincing, for me.
http://photogallery.canberrabirds.org.au/images/Reed-Warbler_Clamorous2_Dabb.jpg
As you say, the beak is spot on.
And I reckon the eye is a fit too. No need to explain away the lack of reddish colour around the eye (as you might need to do with a Wren).
I think we all got this one sorted in quick time. Better than Tarks recent Rose Robin (which turned out to be a Golden Whistler), which went on for ages - and is still being brought up even today (in jest, I am pleased to say).

Steve, re your 15 Black Cockatoos, you might be interested to read a report I published on a storm (a big one) which drove a flock of 27 Black Cockies up out of the rainforest below Macquarie Pass.
http://peonyden.blogspot.com/2008/01/storm-which-hit-sydney-started-at.html

There were possibly more than 27, but that's how many I got in a single image. I commented on the noise - just as you have tonight. A really large flock (as yours is) is amazing to hear fly over.
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Cheers
Denis