The Solitary Sandpiper (Tringa solitaria) is a small wader (shorebird). It is a dumpy wader with a greyish head and breast and otherwise white underparts. It is obvious in flight, with wings dark above and below, and a dark rump and tail centre. The latter feature distinguishes it from the slightly larger and broader-winged, but otherwise very similar, green sandpiper of Europe and Asia, to which it is closely related. The latter species has a brilliant white rump. In flight, the solitary sandpiper has a characteristic three-note whistle. They both have brown wings with little light dots, and a delicate but contrasting neck and chest pattern. In addition, both species nest in trees, unlike most other sandpipers. It has yellow legs and a yellow bill that is black at the outer one-third.