When I first saw this bird I thought it was a chunky Least Sandpiper but it seemed too big - not just too fat! The shape didn't feel right nor the way it carried itself; and the bill seemed too substantial for the little Leasts I'd been seeing. I didn't have a good direct reference for size, and I clicked this shot before working to properly identify it. Subsequently I got a good look, sorted out the size (this was apprecialby bigger than the nearby Least), and got a better look at the breast (next photo) both of which point to Pectoral.