Least is yellow (greenish) and Western is black. First tip, color of the legs. If you have the chance to compare the birds side-by-side, take note of how the western sandpiper’s bill also appears more “droopy” than a least sandpiper’s. In fall, molt timing can be a quick way to separate Western from Semipalmated. This is the sandpiper most likely to be seen on small bodies of water inland. On sandy riverbanks, lake shores, and edges of sewage treatment ponds, little flocks of Least Sandpipers fly up to circle the area and then settle again, giving thin, reedy cries as they go. Least Sandpiper is on the left & Western Sandpiper on right. Western has a larger white patch in the shoulder. Often is hard to tell in poor light, distance, or mud on Least’s legs. Western Sandpipers molt much earlier, with some attaining full basic plumage by August. Western Sandpiper Western is by far the dominant peep on the West Coast, and Western along with Least are the only peeps likely to be seen in North America in winter. They have distinctive yellow-green legs and a high-pitched creep call. Least is a warmer brown than the Western’s gray tone on back. The smallest member of the sandpiper family, no bigger than a sparrow. Least Sandpipers are the smallest of the small sandpipers known as “peeps”—not much bigger than a sparrow.

Western sandpipers have longer, thicker bills with a more blunt tip than the bills of least sandpipers. Look for them on edges of mudflats or marshes, where they walk with a hunched posture and probe for little crustaceans, insects, and other invertebrates. Identification separating these two is fairly straight forward, as the Least Sandpiper has yellowish legs and the Western Sandpiper has black legs.