After returning home from a scrumptious lunch at Lauren's Cafe at Penrose, on September 11, I noticed a raucous mob of Sulpher-crested Cockatoos flying above Penrose Rd and a raptor near them. Grabbing my 10x50s, I found the cockies were 'mobbing' a Grey Goshawk. Interestingly, the birds sort of clustered around, or by, the raptor, but didn't make any great aggressive movement, as a collective, at the Goshawk (the odd cockie half-heartedly went for it). On a couple of occassions, the GG was actually in the middle of the flock of cockies and all the birds were sailing along contentedly.
I find this fascinating. I've seen this behaviour before, with a white morph/phase GG, at Lane Cove National Park in Sydney. I think HANZAB (big deal Australian avian handbook) authors and other birders have an inkling that white GGs do this to disguise themselves when approaching potential prey. I had a grey individual - what can this mean? Maybe, it's just birds together, celebrating their freedom. After about ten minutes of interaction, the GG was left alone to soar a long way above Bundanoon's rooftops.
LJ, September 14 2011.