There are two sets of eggs, one of three and one of two, in the United States National Museum, taken by Louis L. Lane, at Cape Serdze in June, 1912, but no further data came with them.
Eggs.—The small sets referred to above were probably incomplete; doubtless four eggs is the normal set. The six eggs in the Thayer collection are subpyriform in shape and have a slight gloss. The ground color is uniform in all of them; it is between "cinnamon buff" and "dark olive buff," or a warm shade of the latter. Three eggs are finely speckled all over, only a little more thickly at the larger end, with light browns, "tawny" and "snuff brown"; one egg is heavily blotched at the larger end with "Verona brown" and "warm sepia," and only sparingly spotted elsewhere.
J. H. Riley tells me that the eggs taken by Louis Lane vary in ground color from a warm tint of "dark olive buff" to "deep olive buff." The set of two is rather evenly but not heavily marked over the surface with small blotches, dots, and scrawls of two shades of "bister," with a few shell markings of "drab" here and there over the surface. One egg of the set has the "bister" markings larger and thicker on the large end. The other set has the spots larger and heavier at the large end, and in two eggs they are darker, "clove brown" or even "blackish brown." The shape is subpyriform.
The measurements of these 11 eggs average 30.4 by 21.8 millimeters; the eggs showing the four extremes measure 33 by 22.8, 30.5 by 23.3, 28.7 by 20.8, and 29.3 by 20.3 millimeters.
Young.—Regarding incubation and care of the young, Mr. Dixon (1918) writes:
Regarding the time required for incubation, we have only circumstantial evidence to offer, but our observations lead us to believe that about 18 or 20 days elapse between the time the last egg is laid and the first young hatched. The most striking fact in the domestic life of the spoonbilled sandpiper is that the major portion of the household duties, aside from the actual laying of the eggs, is performed by the male and not the female bird. In addition to our own observations, Kleinschmidt also has found this to be the case. In the author's experience, none of the several females taken were found on or within 50 feet of the nest. It is possible, however, that they may have been warned by the male birds and had sneaked off before we were close enough to detect their leaving. In the unequal division of domestic duties conditions among the spoonbills are similar to those among the phalaropes, where the male, after he has been courted and won by the larger and more brilliant female, takes upon himself almost all of the household cares. However, in the case of the spoonbilled sandpiper there is nothing to show that the female does the courting, although she is the larger of the two. The female spoonbill is thus seemingly content to merely lay the eggs, while she lets the male build the nest, incubate the eggs, and take care of the young. In corroboration of the latter statements, the author observed a male bird building a nest at Providence Bay, Siberia, June 22, 1913; another male was flushed repeatedly from a nest containing two fresh eggs near the same place, on the same day, while a third male was found tending three downy young at Cape Serdze, Siberia, on July 17, 1913.
On July 17, 1913, at Cape Serdze, Siberia, while strolling along the spongy green turf beside a fresh-water pond, my attention was attracted by the "broken wing" antics of a spoonbilled sandpiper. Although my eyes remained "glued" on the spot from which the bird arose, no nest or sign of young could be found when I reached the place. Soon a second bird, presumably the female, arrived on the scene. Both appeared much concerned, and from their actions I felt sure that there were young near by. A careful search of the short grass, which was not over 2 inches high, failed to reveal any living creature. I therefore retired to a grassy mound about 20 yards away and awaited developments. Both parent birds, giving their alarm notes, circled about overhead, where they were soon joined by a pair each of Eastern least and Temminck's stints. The two pairs of stints were later found to have broods of downy young in the grass on the opposite shore of the lagoon near by. Soon both spoonbills flew off across the lagoon and disappeared, but the male returned promptly, alighting quietly near the margin of the pond. Here he stood motionless for nearly a minute, and then trotted through the grass directly to the spot from which I had first flushed him. At this point he stood still for another full minute, during which time he looked all around, seemingly to make sure that the coast was clear. Having satisfied himself that no active enemy was in sight he stepped forward and bending over uttered a soft call in a low tone, plee-plee-plee. This call was repeated a second time, and instantly there arose directly in front of him a tiny mouse-like brown form, seemingly rising from out of the very ground. With tottering unsteady steps the downy young sandpiper stumbled and fell toward the parent, who continued calling and encouraging it. Upon my sudden appearance the old bird gave a quick warning note and at this signal the youngster squatted motionless with neck stretched forward on the ground. Although I knew the exact spot where it disappeared, it was some time before I was able to locate the tiny form, so well did it blend with the clump of reddish moss upon which it had squatted. A careful search revealed no other young sandpipers, so I returned to my hiding place. This time I had to wait longer for the male to return, and while I was waiting a second sandpiper, which I believed to be the female, arrived but did not go near or call the young. Two or three minutes elapsed this time between the return of the male and the giving of the low call notes, when, as before, another downy young quickly arose at the signal and toddled over to its parent. After this second experience I was forced to change my hiding place, as the male sandpiper refused to return to the young until I moved. He seemed much concerned upon this last visit, probably realizing that it was high time the young should be hovered and warmed.
I could not understand why all the young had not risen at once in answer to the parent's call, but I noticed that he had in each case gone up to within less than two feet of the one in hiding, and then with lowered head facing the chick, gave the call note. In each case it was the youngster thus directly addressed that responded to the signal and arose. The note of the young was a low rusty squeak, scarcely audible to human ears. It was very similar to the note of the young semipalmated sandpiper. As far as my observations went, there was no attempt on the part of the parent to feed the young, and it is my belief that from the time they are hatched the young spoonbills hunt their own food. The exercise thus gained was found in the case of young semipalmated sandpipers to be essential to the health of the chicks. In addition to keeping warm by running about the young spoonbills are hovered and warmed at regular intervals by the parent. The brood mentioned above had survived a fairly severe snowstorm on the preceding day.