Swifly fly the Needletails

Yesterday afternoon the Spine-tailed Swifts (or if you prefer, White-throated Needletails) were feeding crazily in the balmy weather, obviously finding plenty of flying food.
We sat on the back deck, after a full day of building and painting, and watched a loose flock of Swifts circle and zoom past us. Frequently they were well below tree-top height (which is not more than 20 metres - here). You could hear the wind "whooshing" as they passed over, especially if they did one of those arcing movements, where they tilt themselves on one side and pass over in a gentle curved line. I gave up photographing them, after a while as the light was getting soft, late in the afternoon, and I had adjusted the speed of the lens, firstly to 1/1000th of a second, and then to even faster speeds.
Trouble was, as the light got duller, the images were then too dark to use. Time to just sit back and enjoy the spectacle.

We discussed the question of how many birds there were. We say only 6 or 8 at any one time, and they were certainly doubling back , as sometimes I would hear the rush of their wings come from behind me, whereas normally I see them circling down the valley below me, and then see them fly up the hill, past me.

However, we felt it was impossible to tell if there has a very loose flock of maybe 20 birds, or if we had a been visited by a very much larger flock, spreading themselves out over half an hour or more.

Judging by the number of minor adjustments one could see them making, - fan tail out, slow to a momentary stall, they were feeding actively. There were many minute insects (midges) flying low down, but I suspect these guys were after larger prey. One hopes so, for the energy they expend is extraordinary, and they surely need ot replenish themselves to keep up that level of exercise.

This morning a group of about 30 birds flew past, straight up from the Shoalhaven Valley, heading due north. Their behaviour was very different from what we had seen the day before. These birds were travelling, not feeding.

While I was out photographing the Swifts, I happened to notice this Grey Goshawk fly past on the top of the ridge. Clearly it was keeping a watchful eye on me.And talking of "Needletails", this is one creature which could bear that name too, but Peter referred to is simply as the Great Big Black Bastard - a wasp which Peter was not happy to have hanging around him. It left, after having explored various holes in the equipment on the back deck. Its body was blueish black and the wings had a purple sheen to them.
It is possible (just possible) that this is the male of the more familiar "Blue Bottle" which is the wingless female Diamma bicolor, the Blue Flower Wasp. This species has been reported several times recently on the COG Chat Line, a bird ofruym, but one where occasional creatures of special interest pop-up for ID assistance. If I am off the mark with that ID, I would be grateful to be corrected.