Here they trot to and fro, almost as actively and ceaselessly as so many ants, picking up the inconspicuous worms or larvae from the surface of the ground and seeking them beneath it by thrusting down their sensitive bills quite to the nostrils, after the manner of boring snipe, but less quickly, vigorously, and persistently. They are also given to wading out into shallow water where they pull up good sized masses of aquatic plants, such as Utricularia. By shaking and piercing these with their bills they evidently obtain from them food of some kind, perhaps insect larvae or small Crustacea.
At high tide on the beaches, when the wet sand with its bountiful food supply is covered, great flocks of this species, together with the least sandpiper, the sanderling, and the semipalmated plover, often spend an hour or more huddled together on the dry sand. Each species keeps more or less separate. The birds generally face the wind, but sometimes they arrange themselves in the lee of bits of driftwood or other obstructions, and "tail out" down wind in long streamers as it were, each sheltered by the one next to windward. They sleep standing on one or both legs with the bill tucked under the feathers of the back—not "under the wing" as in poems—or they squat down, resting their breasts on the sand. They occasionally seem to yawn by stretching one wing over a leg. They also spread both wings above the back as do many other shore birds, and they flirt the bill nervously from side to side, to relieve their ennui, perhaps shaking the head at the same time.
Voice.—The varied courtship songs and notes have been described above. Their call note, to my ears, is very much like that of the least sandpiper, but shriller and less melodious. A harsh rasping note and a peeping sound are also given and a low, rolling gossipy note is often emitted when they approach other birds or decoys, a note that used to be imitated with deadly effect by gunners. John T. Nichols (1920) says:
The flight note of the semipalmated sandpiper is a rather loud "cherk," softer and less reedy than the analogous krieker "kerr." It is commonly modified to a softer "cher" or "che," which with much variation becomes the conversational twittering of members of a feeding flock. Soft short, snappy "chips" are characteristic of flocks maneuvering about decoys * * * Hurried cheeping notes ("ki-i-ip") on being flushed, are suggestive of the same note of the krieker.
Field marks.—These have been discussed at length under least sandpiper to which the reader is referred, but may be summed up here as follows: a little larger than the least sandpiper, grayer, bill stouter and straight, tarsi and feet black, semipalmated. The young can be distinguished from the old in the field by their nearly white breasts washed with a smoky tint. In the hand their tarsi are seen to be black with a slight greenish hue.
Game.—The fact that so many of these birds could be easily killed at one shot, and the fact that they were so fat and palatable broiled or cooked in a pie, made them always much sought after by the pot hunter. As large shore birds grew scarcer and it became more and more difficult for the gunner to fill his bag with them, "peep" shooting, even by sportsmen, was in vogue. The Federal law has now wisely removed this species from the list of game birds and prevented its extinction. The bird has responded to this protection in a marked degree, and flocks of 500 or more are common and pleasing sights on our beaches where one-tenth of this number was once rare.
The shooting of semipalmated sandpipers occurred largely on the beaches. The gunner dug a hole in the sand, banked it up, and put brush and driftwood, often reinforced with seaweed, on the ramparts. At a convenient distance decoys of wood or tin were placed, arranged like a flock of birds with their heads pointing to the wind. Occasionally large clamshells were stuck in the sand, simulating very well a flock of peep. Much depended on the skill of the gunner in calling down the birds as they flew along, by cunningly imitating their notes and by his care in keeping concealed and motionless until the moment that he delivered his fire. To bring down a score of birds from a closely packed flock required but little skill, where, to pick off a single peep, flying erratically and swiftly by, called for well-seasoned judgment; but the chances for these birds were small indeed when the beaches were lined with inviting decoys and concealed whistling gunners.
Fall.—On the New England coast the semipalmated sandpiper is a little later in migration than its colleague, the least sandpiper. July 10 to October 30 are the usual dates, but few are seen after September 20. The adults come first, but after the middle of August the young appear, to be distinguished by their nearly white breasts washed with a smoky tint, and by their more unsuspecting ways.
The extraordinary abundance of this species at certain times on migration is well illustrated by what Stuart T. Danforth (1925) says of it in Porto Rico. He writes:
The semipalmated sandpiper is by far the most abundant shore bird at Cartagena Lagoon, though it occurs only as a fall migrant. I have records from August 13 to October 20, 1924. During the latter part of August they are present in almost unbelievable numbers. I hardly dare estimate their numbers, but on August 26, when they were at the height of their abundance, I am sure that 100,000 would have been a low estimate of their numbers. They simply swarmed over the mud flats. On this date, although I was trying to avoid shooting them, I got 16 while shooting other birds. They were so abundant that stray shots could not help killing numbers of them. On other days many were also unintentionally shot in the same manner. In fact, all but 4 of the 36 that I collected were shot in this way. This species prefers the mud flats, but when they were so excessively abundant some were forced to feed in the sedge and grass associations, and when the fall rains came a little later practically all of them were forced to the sedges and grasses and even to the cane fields. But within a few days after this most of them left for parts unknown.