The Red-necked Stint breeds in the high Arctic in eastern Siberia and Alaska. It is a non-breeding summer visitor to southeast Asia and the southwest Pacific including Australia. The final clip shows a bird with a reddish neck as it transitions into breeding plumage before going back to the Arctic!
Often seen with the larger Sharp-tailed Sandpiper see:- vimeo.com/158591389
Also at birdsofaustralia.video/index.php/red-necked-stint-calidris-ruficollis/