Barndoogles of Bats

Birding has been almost non-existent here in the lower Blue Mtns this week, but last night with family witnessed an impressive bat event on the shores of the Nepean River at Penrith.  Just as it was getting dark, large flying foxes appeared in silhoutte flying along the river from north to south.  From an estimated 50 going past a second, and the 17 minute duration and allowing for a little tailing off at the end I reckoned there were just under 50,000 ± 20,000 of them.  The only other bat event of this size I have personally witnessed was in Charters Towers north Qld some decades ago.  If anyone knows of any current Sydney colonies and their sizes I'd be interested to hear.

Julian