The western race of this species is larger than the eastern. In adult nuptial plumage the upper parts are much less distinctly spotted with whitish, the white bars on the tail are decidedly narrower and the outer primary is usually finely mottled, with ashy white along the border of its inner web; this last is none too constant a character and is sometimes seen in the eastern bird. The name was derived from the fact that in young birds the light spots on the back, scapulars and wing coverts are brownish cinnamon instead of white or buffy whitish.

Courtship.—The following description of the song flight of this species was originally recorded by Dr. Joseph Grinnell (1900) under the name of the undivided species, but he now evidently thinks that it should belong here:

The song flight of this species is mostly indulged in during the early morning hours. This consists of a slow circuitous flight on rapidly beating wings high over the tree tops, accompanied by the frequent repetition of a weak song somewhat resembling the call of a sparrow hawk. At the close of this song flight the bird alights, as if exhausted, and perches silently for some time at the top of the tallest spruce in the vicinity. During the performance of the male, the female may be seen feeding around some grassy pool beneath, from all appearances entirely unmindful of the ecstatic efforts of her mate.

Nesting.—Nothing definite is known of the breeding range or nesting habits of the western solitary sandpiper. It is supposed to breed in the interior of British Columbia and Alaska. The following observations, made near Circle, Alaska, by Dr. Wilfred H. Osgood (1909) throw some light on the subject:

Within a radius of several miles from Circle one or more adults were found about almost every woodland swamp. In most cases they acted like parent birds anxious for the safety of their young. Whenever we entered certain precincts, they hovered nervously about, calling loudly, or alighted on nearby trees scolding. The first pair seen near Charlie Creek exhibited such actions on the evening of June 22, and we made a hasty search in the twilight for young birds, but found nothing. The excitement of the old birds seemed to be greatest while we were in a small grassy swamp, so the next day we made a more careful search. The old birds were even more excited than before, and it was some time before we detected that, besides the loud cries ringing all about us, a faint peeping was issuing from several points in the grass. Guided by this scarcely audible peeping, we soon found three downy young birds widely separated and squatting aimlessly in the grass. They are quite small, exactly of a size, and none shows the least indication of growing feathers; evidently they belonged to one clutch, and could not have been out of the eggs more than one or two days. The eggs of this species, like those of the European green sandpiper, have been found in the nests of other birds in trees. The small opening where the birds were found was bounded on one side by an extensive area grown with willows of relatively small size, but on the other side was only a thin line of willows and then alders, birch, poplars, and heavy spruce, in which probably such birds as olive-backed thrushes, robins, and varied thrushes nested in abundance. Therefore there was ample opportunity for the sandpipers to lay their eggs in the nests of these birds.

Plumages.—The downy young referred to above are thus described by Robert Ridgway, (1919):

General color of upper parts cinnamon drab, longitudinally varied with brownish black; forehead and crown with a broad median streak of black; a sharply defined black loral streak, extending from bill to eye; a narrow black stripe across auricular region (longitudinally), or a black postauricular spot; occiput brown centrally, black exteriorly, the black border sending from each side a forward branch; an oval patch of brownish black on median portion of rump, this bordered along each side by a stripe of pale dull vinaceous-buff, the two buffy stripes converging or almost uniting both anteriorly and posteriorly; wings cinnamon drab, margined posteriorly with dull white, the brown portion with several irregular spots or blotches of black; under parts dull white.

Subsequent plumages and molts are doubtless similar to those of the eastern race.

Winter.—As mentioned under the preceding subspecies, we know very little about the winter distribution of the two races. Dr. Frank M. Chapman (1926) says that most of his specimens from Ecuador are of this form, which he calls “a common winter resident from the coast to the tableland, arriving from the north at least as early as August 10.” Dr. Alexander Wetmore (1926) says:

The specimens taken at Formosa and General Roca belong certainly to the western form, on the basis of size (male, wing, 134.3; female, wing 136.7 mm.), dorsal coloration, and the presence of mottling on the inner web of the outer primary. A female from Lazcano, Uruguay, has molted the outer primaries, but on the basis of other measurements and on the presence of some dark, buff mottling on the back seems within the limit of variation of cinnamomea and is identified as the same as the other two. Though the typical subspecies solitaria is recorded definitely from Colombia by Chapman, these findings seem to cast a doubt on its presence as far south as Argentina.

DISTRIBUTION

Range.—Western North America and South America.

Breeding range.—No unquestioned set of eggs of the western solitary sandpiper has thus far been recorded. Downy young with their parents have, however, been taken in western Alberta (Henry House) and in Alaska (Circle, Kowak River, Eagle, and Charlie Creek). There also is a strong probability of their breeding in British Columbia (Cariboo District, and Ducks).

Winter range.—As mentioned under T. s. solitaria, the two races of this species on their wintering grounds in South America have been distinguished only on a few occasions. It is probable that they either occupy the same winter grounds or that their ranges overlap. All specimens collected by Wetmore (1926) from Uruguay, Paraguay, and Argentina, prove to be this form, indicating that it may winter south of true solitaria. It also has been taken by Chapman in Ecuador (Guayaquil, Loja, and Cebollal).

Spring migration.—Early dates of spring arrival are: Texas, Samuels, April 15, and Henrietta, April 19; New Mexico, State College, May 4, and Las Vegas, May 8; Colorado, Colorado Springs, May 1, Denver, May 4, and Boulder, May 5; Montana, Terry, May 7, and Billings, May 10; Alberta, Athabaska Landing, May 5, Edmonton, May 10, and Sandy Creek, May 14; Mackenzie, Fort Simpson, May 10, and Fort Providence, May 14; Arizona, Verde Valley, April 20, and Paradise, May 9; California, Los Angeles, April 10, Gridley, April 23, and Fort Crook, May 4; Oregon, Anthony, April 16, and Malheur Lake, April 17; Washington, Tacoma, May 6; British Columbia, Okanagan Landing, May 5, and Chilliwack, May 7; Yukon, Forty-mile, May 8; and Alaska, Tocatna Forks, May 12, Nulato, May 15, and Kowak River, May 18.

Late dates of spring departure are: Colorado, Boulder, May 25, Denver, May 28, and Grand Junction, June 3; and Wyoming, Fort Saders, May 25.

Fall migration.—Early dates of fall arrival are: California, Santa Barbara, July 22; Arizona, Apache, July 29, Cave Spring, August 1, and White Mountains, August 10; Montana, Terry, June 28; Wyoming, New Castle, July 7; Colorado, Lytle, July 6, Middle Park, July 13, and El Paso County, July 23; New Mexico, Zuni Mountains, July 24; and Texas, Brownsville, July 31.

Late dates of fall departure are: Alaska, Taku River, September 15; British Columbia, Okanagan Landing, September 26; Washington, Seattle, September 11; California, Santa Barbara, September 7; Arizona, San Pedro River, October 10; Lower California, Agua Escondido, November 18; Montana, Missoula, September 4, Terry, September 5, and Bitterroot Valley, September 7; Wyoming, Yellowstone Park, September 4, and Green River, September 5; Colorado, Boulder, September 18, Florissant, October 5, and Greeley, October 25; and New Mexico, Acoma, September 27, and Glenrio, October 2.