Thanks for your reply but I would find it very strange to be a Wonga Pigeon as this is a park in Suburbian Melbourne and the sound was coming from the reeds around small lakes, their was Clamourous Reed Warblers there and various other water birds also greenfinch, superb fairywren etc and it seemed to move quickly to the other side of me when I got close to one area and I think a Wonga pigeon would make noisy rustling sound in the reeds, but you have inspired me to go back to that park and research more. Cheers.