Adults have a partial prenuptial molt in the spring, from February to June, which involves the body plumage, except the back and rump and some of the scapulars, tertials, and wing coverts. The complete postnuptial molt of adults is much prolonged; the body molt begins in August, but the wings are not molted until the bird reaches its winter home, beginning in October and often lasting until February. Two adult females taken by Doctor Wetmore (1926) on September 9 in Paraguay "were in worn breeding plumage with no indication of molt." And one shot in Uruguay February 8 had renewed all but a few feathers of the entire plumage, while a male taken the same day was molting its primaries. There is very little difference between the summer and winter plumages; the feather edgings of the upper parts are more rufous in summer and more ashy in winter. _Food._--According to Preble and McAtee (1923), the contents of 21 well-filled gizzards of this species consisted principally of "flies (Diptera), 54.5 per cent; amphipods, 22.3 per cent; vegetable matter, chiefly algae, 10.5 per cent; beetles, 8 per cent; Hymenoptera, 2.1 per cent; and bugs (Hemiptera), 1.3 per cent." Other things eaten were mites, spiders, and caddis fly larvae and a few seeds of grass, lupine, and violet. P. L. Hatch (1892) says that "their food is principally crickets in spring, interlarded with various dry-land larvae, small beetles, and ground worms. In the fall the grasshoppers are first chosen, after which crickets and whatever other insects prevail at this season." Birds taken by B. S. Bowdish (1902) in Porto Rico had eaten fiddler crabs. Pectoral sandpipers feed mainly in grassy meadows, more or less dry, and their food is chiefly insects. _Behavior._--On the grassy salt meadows, where we usually find it, I have often been impressed with the resemblance of this sandpiper and the Wilson snipe, both in appearance and in behavior. It is often found in wisps or scattered flocks, the individuals widely separated and crouching in the grass. Often it flushes close at hand with a startling harsh cry and dashes hurriedly away with a zigzag flight. Sometimes it flutters away for only a short distance and drops quickly into the grass. Again it makes a long flight, circling high in the air and then pitches down suddenly in some distant part of the marsh, or perhaps near the starting point. Though erratic at first, the flight is swift and direct when well under way. They sometimes fly in flocks like other sandpipers, but more often they are flushed singly. They usually flock by themselves but are sometimes associated, purely fortuitously I believe, with other species that frequent similar feeding grounds, such as Wilson snipe, Baird, least or semipalmated sandpipers.