The claim of this species to a place in the North American list dates back to Audubon, who obtained three specimens on Sand Key, near Cape Sable, Florida. Since that occurrence no other specimens have been obtained.
Courtship.—There are few species the study of whose family life is attended with greater difficulties than the greenshank. In the first place it is an exceedingly wary and keen-sighted bird, and furthermore, it is not sociable during the breeding season, each pair nesting apart from its fellows in some of the wildest and most desolate country imaginable. In the British Isles its main breeding grounds are on the vast expanse of sodden moorland, interspersed here and there by lochs and "flows" (stretches of water-logged ground with black peaty pools), which cover a great part of the Scottish counties of Sutherland, Caithness, and Ross. Further southward it also breeds on suitable ground in Inverness-shire and other parts, but here the country is more broken and varied and there are big stretches of old pine forest and more modern coniferous plantations. In both classes of country observation is attended with difficulties. On the open treeless moorlands houses are few and far between, the climate is anything but inviting in early May, rainstorms are frequent, varied by squalls of hail and fogs, while in some seasons heavy snowfalls take place from time to time. On the other hand the country is open, with few hills of any size, and the direction of the birds' flight can be marked for long distances, while further south, though the extent of possible breeding ground is infinitely smaller, it is far more difficult to follow a bird in flight as it skims over a belt of forest or round a shoulder of a hill. So it is little wonder that of the actual courtship of the greenshank we have hardly anything on record. What little we know may be classified under two heads; the wonderful song flight of the male and the ritual of the courtship itself. The song flight may be seen even after incubation has begun, though possibly only in the earlier stages, and has been noticed by several observers. The fullest and best description is that of Mr. J. Walpole Bond (1923), which may be summarized as follows:
When singing, the greenshank rises fairly high—sometimes very high—above the moor and starts by soaring, head to wind, of course. It may then remain soaring, looking very hawklike indeed, while it sings. Or else—and this generally happens—it varies the performance by proceeding in a succession of downward, inverted arcs of good size, though soaring is resumed for a few moments as the summit of each curve is reached. In this case "singing" only takes place on the downward portion of the curve; on the down curve, too, the wings are sometimes vibrated very rapidly. Sometimes also when the "song" itself is in progress the wings are flicked up and down with measured rhythm.
The song itself is a musical and moderately fast repeated dissyllable tew-hoo, a rich note, harmonizing with the desolate surroundings in which bird life, except for an occasional meadow pipit, (Anthus pratensis) is often almost entirely absent. Walpole Bond also notes a twanging and metallic chuck, dock, or duk, sometimes heard after each quick tew-hoo, and questions whether this latter sound is vocal or caused by wings or tail. Personally I have not noticed the latter sound, perhaps because I have generally heard the song at a great height and always at some distance. It should be added that this performance is often kept up for long periods. Gilroy (1922) mentions a case when it lasted for twenty minutes, and though I have not timed the birds, I have heard it more or less continually for ten or twelve minutes, ending with a precipitate dive earthwards. Of the actual courtship ritual I have seen no published record. The birds arrive on their breeding ground early in April. On an occasion when a heavy snowfall had practically wiped out all early nests on the Caithness-Sutherland moors, I saw two birds on a little sandy spit by the side of a small loch. The male was evidently pressing his attentions on his mate and approached her with high flapping wings, showing the underside almost as the redshank does, and actually raising his wing over the hen until at last coition took place. Both birds remained quiet for some little time afterwards and then rose together and flew away, calling all the time.
Nesting.—The information with regard to the nesting habits in all the older works is of the baldest and scantiest nature, but the last decade has seen a great advance in our knowledge and Mr. N. Gilroy (1922) in particular has published a fascinating little pamphlet on this bird in which his observations on over twenty nests examined between 1906 and 1922 are carefully coordinated, so that now the actions and movements of breeding birds are much better understood. The whole account is of the deepest interest, but as it extends to some twenty pages it is only possible here to give a short résumé of the present stage of our knowledge. The greenshank generally nests within easy reach of some small lochan, often a mere pool, to which the young can easily be led by the parents soon after they are hatched out. The nest itself is usually on dry ground. On the treeless moorlands of Southerland Caithness it is almost always made either close up against or actually on one of the many grey bits of rock lying amongst the heather. Exceptionally it has been found on the top of a hummock, but as a rule should be looked for within a few hundred yards of the feeding ground, sometimes quite exposed but difficult to see as the sitting bird exactly resembles in color the grey stones lying about and generally sits till almost trodden on. In the Inverness country the birds nest close to a mark, just as the Sutherland birds do, but here instead of a grey boulder it is usually a bit of bleached and dead pine, of which thousands of fragments lie scattered about. Exceptionally I have known a bird make use of an iron fence post as a mark. When a bird has been found standing about the edge of some tiny pool the probability is that his mate is sitting not far away, but the difficulty of finding her is vastly increased by the fact that the main feeding ground is generally by the side of a good-sized lake, which may be any distance from one to four miles away, and here one of the pair may spend the greater part of the day. Moreover, it is not uncommon to find that several pairs of birds use the same lakeside as their main resting and feeding ground. Even so, if the sexes changed duties at short intervals or behaved in exactly the same manner, it would not be a matter of great difficulty to trace a bird back to its nesting ground. But there seems to be considerable individual variation in this respect. There is, however, a very strong tendency to return to the same breeding place year after year. The classical case is T. E. Buckley's record of a nest found between two stones which was again occupied two seasons later presumably by the same bird, but there are innumerable cases where two or three nesting sites, used in as many years, lie within one hundred yards of one another. This makes the discovery of nests much easier if one can revisit the district for two or more years in succession. New nests are merely saucer-like depressions with a few heather stalks and some dead bents, but almost always some leaves of bay myrtle or bilberry in the hollow, and if the bird has begun to sit, some of its own small breast feathers.
Eggs.—Normally, four in number, occasionally only three, while five have occurred; second layings usually consist of three eggs. Larger numbers, such as eight, recorded by Booth, are probably due either to two hens laying together or one clutch spoilt by weather and a second laid subsequently. They are pyriform in shape and wonderfully handsome, the ground color varies from stone color to warm buff, marked sometimes sparingly and sometimes freely with irregular spots and blotches of deep red-brown, as well as ashy or purplish shell marks. In most eggs the markings are heavier at the large end. The measurements of 100 eggs average 51.41 by 34.80 millimeters; the eggs showing the four extremes measure 59.8 by 37.7, 45.8 by 35.4, and 50.4 by 32.4 millimeters.
Young.—That incubation is sometimes shared by both sexes is proved by the fact that both Walpole Bond and Seton Gordon have witnessed the change of duties and the latter has actually photographed the birds in the act of changing places. Yet Gilroy watched one bird from 10.45 a. m. to 7.50 p. m., which remained all the time at a loch side in Sutherland on May 16, although its mate was sitting on a clutch of fresh eggs. Evidently there is considerable individual variation in this respect.
Plumages.—The molts and plumages are fully described in "A Practical Handbook of British Birds," edited by H. F. Witherby (1920), to which the reader is referred.
Food.—During the breeding season the food consists chiefly of insects and their larvae, but tadpoles and frog spawn are freely taken and Oswin Lee records a pair feeding busily for nearly an hour in the evening on them, and small water beetles. Freshwater mollusca, such as Planorbis, are also taken and occasionally a small fish. Along insects the following genera of Coleoptera have been recorded: Phyllopertha, Cneorhinus, Harpalus, Dytiscus, Gyrinus, Aphodius, and Ilybius. Among Diptera, Tipula and their larvae; also Notonecta glauca and Lestes nympha. In the autumn and winter a great part of the food is picked up on the coast and includes worms, lug-worms, crustacea (Palaemon, Crangon, Hippolyte, Squilla, and in large numbers Gammaridae).
Behavior.—Although a large proportion of its breeding area is absolutely devoid of trees, the greenshank also nests in country intersected by belts of forest, and it is interesting to note that it perches readily on trees and makes good use of them as lookout posts. It is always wary and readily takes alarm, rising with loud outcry on the approach of danger. As MacGillivray notes, when searching for food it often wades out into the water until it reaches nearly to the tarsal joint and moves "with rapidity, running rather than walking and almost constantly vibrating its body." It is interesting to note the difference in the behavior of individual birds under similar circumstances. As a rule the incubating bird sits very closely and will sometimes allow herself to be touched before leaving the eggs. When flushed one bird will spring up and dart away with rapid flight and a single cry of alarm, another will for a minute or two fly about with deafening clamor, and in one case a bird dashed off but pitched about five yards away, yelping loudly and next minute flew straight at my head, with repeated cries of Ip, chip, chip, ip, chip, chip, etc. Just as it reached me it sheered off with its long green legs dangling, but returned to the charge again, repeating the process ten or twelve times, after which it settled on the ground and called vociferously, but after 10 minutes had passed flew away still calling. This behavior was, of course, quite exceptional.