Behavior.—The flight of the greater yellow-legs is quite swift, strong, and well sustained on the downward and sweeping strokes of its long, pointed, dark-colored wings. Its long neck and bill extended forward and its long, yellow legs stretched out behind give it a slender, rakish appearance which is quite distinctive. It usually flies at a good elevation and when traveling it often flies at a great height. It scans the ground beneath, looking for a suitable place to feed or searching for desirable companions. It responds readily to the call of its own species and will often answer an imitation of its notes from a great distance; sometimes when it is too far away to be seen. When coming in from a distance it usually flies in wide circles around the caller several times until it is satisfied that it is safe to alight. It then comes zigzagging or scaling down on down-curved wings and settles lightly near its would-be companions. On alighting it stands for a moment with its wings extended upward in a graceful attitude, folds them deliberately, gives a few jerky bows or upward nods, and then either begins to feed or settles down to rest. It is not very particular as to its companions; it associates freely with any of the smaller waders that frequent the mud flats, meadows, or shallow ponds; it seems to be particularly fond of the companionship of the teals when they are feeding in shallow water. It is not as gregarious as the lesser yellow-legs; it is most often seen singly or in small parties, but I have counted as many as 40 in a flock on rare occasions.
When walking on the ground its movements are lively and its carriage is graceful, though its long legs seem to give it a somewhat jerky gait at times. On its breeding ground it often alights on the tops of spruce or larch trees, or on bushes or dead stubs, on which it balances rather awkwardly. It is normally a shy and wary species; large flocks are very difficult to approach; but sometimes single individuals seem to be absurdly tame in the presence of other tame species or among decoys. Some good photographs of it have been taken at short range. William Brewster (1925) tells of one that he approached in the open to within ten feet and then fired his gun directly over it without causing it to fly. Mr. Nichols suggests, in his notes:
It would seem almost as though these birds drew an abstract danger line, difficult to cross from the outside without alarming them, but once inside which, man became to them a mere harmless item of the landscape. I have had a greater yellow-legs, a bird of the year, come to decoys (under the impression that they were others of its kind) and as the water was too deep, alight and stand on one of the decoys, recognizing in it a piece of wood, meanwhile being remarkably tame, perhaps waiting for others of the flock (of decoys) to take alarm. Is not this pragmatic rather than rational philosophy which they possess, the weakness most in favor of the gunner who hunts shore birds with decoys?
He also adds the following notes on behavior:
I have seen the greater yellow-legs preen its plumage in leisurely manner without repeatedly dipping the bill in the water, as the lesser frequently does. It reached far back over its shoulder, lifted a wing slightly to pick under it, stretched its neck up to reach the breast with its bill, and scratched its chin deliberately with the right foot. On another occasion a bathing bird crouched down in shallow water, ducking the head and at the same time fluttering and splashing vigorously with the wings.
A resting bird stands at ease, neck hunched down, with slight alert movements of the head. From time to time it may turn its bill back and bury it in the feathers along the back with a little shake of same, one eye at least exposed and open though blinking sleepily. An interesting pose which may be assumed for two or three minutes is with the bill resting diagonally downward across the feathers of the breast. It may stand for a long time on one motionless straight leg, inclined so as to bring the foot under its center of gravity, the other leg raised and concealed by the feathers.
Though a wounded lesser yellow-legs will sometimes dive and swim under water, I have not seen the smaller species alight in spots too deep for wading. The greater yellow-legs on the other hand does so not infrequently. It swims gracefully with phalaropelike motion of the neck, held erect, stern tilted up like that of a gull. In shallow water over mud so soft and sticky that it made wading difficult I have seen a bird launch itself forward, swimming, as the easier method of propulsion.
Voice.—Mr. Nichols (1920) has published the results of a detailed study of the vocabularies of the two yellow-legs, which are noted for the variety of their calls. He has recognized and described nine different calls of the greater yellow-legs, as follows:
(1) The yodle (a rolling toowhee toowhee, etc.) is commonest in a flock from birds remaining in one locality, not traveling. I think I have heard it from a single bird in the fog. It is characteristically given in the air, generally with set wings, by birds which seem to contemplate alighting. It advertises birds tarrying in one general locality, and has probably the function of location notice. It is doubtless homologous with the gather call of the spotted sandpiper with which it has little analogy.
(2) Loud ringing 3, wheu wheu wheu. The characteristic cry of the species, spring and fall. It is commonly given by passing or leaving birds. It advertises the species—and a change of policy in the individual according to its loudness. Analogous with notes of other species spoken of as flight notes or identification notes; occasionally heard from an alighted bird. This call is subject to considerable variation, when heard from a bird about to drop down and join others feeding it is comparatively low-pitched and even, leaving or about to leave a feeding ground, highly modulated.
(3) Four wheus, heard as follows, seem to have a rather definite significance: low, hurried, descending, heard from a bird leaving companion; short, clear, four, by a following bird; loud, four, bird without intention of alighting, trying to flush decoys. This may be called a recruiting call.
(4) Twos (wheu wheu) seem to be characteristic of a recruit. A "gentle" bird which comes nicely to decoys is apt to call in twos when approaching and coming in.
(5) Rarely, in taking wing in the presence of an intruder, a single bird utters a string of unmodulated wheus which breaks up into threes or fours as it goes off. This is likely a note of protest, which would be more common in the breeding season.
(6) Conversational murmuring, from a flock dropping in, expresses companionship and confidence.
(7) Conversational chup notes from birds about to alight, also heard from birds alighted, moving about at ease. The alighting note.
(8) Unloud chups identical with the preceding but more hurried, given by a small flock of birds as they take wing. The flushing note.
(9) Kyow, common in spring, only rarely heard in southward migration; probably associated with the breeding season; seems to express suspicion.
Different renderings of some of the above notes have been given by others. Mr. Brewster (1883) describes a note heard on the breeding grounds as "an incessant clack-clack-clack-clack, which sounded very like the clatter of a mowing machine." He then goes on to say: "In addition to the cry already described, they uttered a rolling pheu-pheu-phe, pheu-pheu-phe, repeated a dozen times or more in quick succession; a mellow pheu, pheu, pheu, resembling the whistle of the fish hawk; and a soft, hollow hoo, whoo, whoo, very like the cooing of a dove. The latter note was given only when the bird perched on the top of some tall spruce."