Wednesday 8 March 2023

Full Moon and Bats

 It had been suggested to me that the evening of the 7th with a full moon would be a good time to watch the bats fly out.  This post starts with a preview, of moon set at 0552 that morning.

We went to Lakeside Drive near the intersection with Karbeethong Rd and, using my compass app, found the bearing of moonrise to point more or less directly at Howe Hill.  This image was taken at 0738, 3 minutes begore moonrise was scheduled.
Allowing for the ridge of the Howe at 0751 this is pretty much on time (or, to give credit/blame where it it due, the time on my camera is set quite accurately).
0754: the background colours vary a little according to which mode I used!
The first bats emerge 0754.
An attempt to get one crossing the moon.  This failed as the brightness of the moon obliterated the bats: they disappeared as they crossed the disc.
This was the closest I got, with a wingtip dipping in.
The camp empties en masse 1958hrs.
The line in the water becomes clear 1959hrs.
The flock gets denser.  I counted 111 bats in this image and estimated it was taking an average bat 8 seconds to cross the image pane, giving - on possibly rubbery logic - 830 bats per minute.  As the flight had pretty much stopped by 2004hrs my guess is there are (8*830  = 6640, plus a few heading out the back to other feeding sites) call it 7,000, bats in the colony at present.

I think this is the best line in the water still with a few mammals!.


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