The name Dunlin comes from the dull brownish winter plumage of this species, specifically from the color dun which is like the color of wet sand. The old name for the Dunlin, at least in North America, was the Red-backed Sandpiper of course due to the wonderfully bright plumage of Dunlins in summer. This is a good name for our Dunlin, particularly as the New World populations are much brighter red on the upperparts than most Old World forms. The Dunlin shows a wide amount of geographic variation, not unexpected given that it nests throughout the Arctic from North America, to Europe and Asia. It is one of the hardiest of shorebirds, wintering relatively far north. In the New World it is also unusual in its migratory behavior, waiting until late in the season to return from the Arctic, with the earliest arriving in late September and most coming down in October. Also unusual is that adults and juveniles migrate south together, quite unlike the typical shorebird migratory pattern and curious in that European populations do not do this. Being among the hardiest of our shorebirds, Dunlins seldom winter south of Mexico, although vagrants are found farther south at times. The Dunlin is the size of a Sanderling but darker in winter, and shows a long and noticeably decurved bill, like a miniature Whimbrel (Numenius phaeopus).