It might surprise you that all these were captured while I made a point of keeping my feet in exactly the same spot - over a period of about 5 minutes. Counting later, flocks of flying ducks and flying cockatoos were found to have about
200 birds each. Other species included a dozen each of Little Ravens and Common Mynas, the whistling ducks also being visible. My estimate is well over a thousand birds.
Postscript: While I was standing in the same spot the amiable farmer drove by and we exchanged a few words about the spectacle. “They’re all mine”, he said (jokingly) “including those Darwin Ducks (sic)”.