Stills from a brief snatch of video in February at Richmond Lake, south of Perth Australia. I have a couple of thoughts but would love to know if anyone more expert than I can help. Pic 1 was the first view before I tried to zoom in (pic 2), then it went blurry but pic 3 shows the tail I believe below the blurred body with the legs pointing left. Pic 4 gives a vague idea of the whole bird which seemed to have streaks to half way down the chest/belly then whitish to the tail.