Taken and cropped from full zoom video in February this year at Richmond Lake, Rockingham just south of Perth, these may be 3 different birds or all the same! Bird 1 in pics 1 and 2 seems to have very clear white versus dark plumage and white head; Bird 2 (pic3) seems to have grey on half of head; Bird 3 (pics 4 and 5) seems darker backed with long seemingly straight bill and darker patch on shoulder. Any clues gratefully received. Thank you in advance.