According to the Rev. F. C. R. Jourdain:

This species is now known to be divided into two fairly distinguishable subspecies, the typical race breeding in Mongolia, Kamchatka, and Eastern Siberia as well as on the Commander Islands, and wintering from the Philippines, Celebes, etc., to New Guinea and Australia. It is this form which has occurred in Alaska. Charadrius mongolus atrifrons Wagler, the western race, breeds from the Kirghis Steppes in South Russia to the Himalayas and Tibet, wintering in East Africa, Madagascar, the Seychelles, India, Malacca, and the Great Sunda Isles.

Like several other Asiatic species, it occasionally wanders across Bering Strait into extreme northwestern Alaska. Joseph Dixon (1918) throws considerable doubt over the time-honored record of specimens supposed to have been taken by Captain Moore of the plover on the Choris Peninsula in the summer of 1849; his reasoning, which seems to be sound, suggests that these specimens were probably taken on the Siberian side. However, Alfred M. Bailey (1926) collected a male of this species at Cape Prince of Wales on June 11, 1922, of which he says:

The tundra was still snow covered, only a small, sandy strip being bare along Lopp Lagoon, and there I found this little wanderer from the Siberian shore in company with yellow wagtails. A south wind had been blowing for a few days previous, which changed to the north the evening before. On these changes of winds I observed that Old World birds were likely to drift across the channel.

Harry S. Swarth has very kindly given me, in advance of publication by the California Academy of Sciences, the latest records of the occurrence of this species in Alaska. While collecting for the academy on Nunivak Island, C. G. Harrold took two specimens, a female on August 14 and a male on September 1, 1927. Two others were seen on August 14, one on September 11, and one on September 13. It looks as if this might be more than a casual straggler in Alaska.

Dr. Leonhard Stejneger (1885) writes:

The Mongolian plover is a very common resident on the Commander Islands; in fact, one of the most characteristic birds of their fauna. It is one of the brightest and handsomest shore birds, and is always gladly welcomed when making its appearance during the first half of May. I used then to watch with delight these elegant runners, wondering at the almost incredible rapidity with which they move their legs when chasing each other over the pebbly beach, or trying to escape the approaching hunter. Very soon, however, the pairs retire to the place chosen for the summer home, and, as soon as the eggs are laid, the birds become more shy and do not expose themselves as much as they did before.

Nesting.—There are three sets of eggs in the United States National Museum taken by Doctor Stejneger in the Commander Islands “during the first days of June.” He says that the birds “do not fly directly from the nest but run away a distance from it before taking wing,” which makes it difficult to find the nests. A nest he describes—

Was found on the islet Toporkof, on the 4th of June, 1883, and contained three eggs. They were lying, with their pointed ends inwards and downwards, in a slight hollow in the ground between the stems of four Angelica archangelica. Dry particles of the leaves and stems of this plant, and numerous seeds of the same, formed the nest, being evidently brought together by the bird itself. The situation of the nest was about 40 feet from the line of high water and about 14 feet above the level of the sea.

Mr. Jourdain contributes the following:

Interesting confirmation of Doctor Stejneger’s observations on the breeding habits and eggs of this species have been furnished by the recent discovery of the breeding haunts of the western race by Messrs. H. Whistler (1925) and B. B. Osmaston (1927) at high altitudes in the Himalayan range. Mr. Whistler found at least five pairs breeding on the stony wastes near the Chandra Lake in Lahul, at 14,000 feet on July 10 to 11. Two clutches, each of three well-incubated eggs and one brood of three downy young were taken. Other pairs were subsequently found breeding in Spiti (13,500 ft.) and on the northern slopes of the Bara Lacha range. Mr. B. B. Osmaston found this species not uncommon in South and East Ladakh in summer, between 13,000 and 15,500 feet. It was located as breeding in Rukshu near the Tsokar and Tso Morari Lakes at about 15,000 feet and between the Indus and Shushal at 14,000 to 14,500 feet, by the Pangong Lake at 14,000 and in the upper Surun Valley at 13,000 feet.

In every case three eggs or young were found and the nest was a slight depression in the sand, among shingle (Osmaston, 1927), or in hollows among the trailing stems of a small creeping ground plant with a woodlike stem, sparingly lined with broken chips and fragments of the plant stems (Whistler 1925).

Eggs.—The nine eggs collected by Doctor Stejneger vary in shape from ovate to ovate pyriform and they show no gloss. The ground colors vary from “cinnamon buff” to “deep olive buff.” They are quite evenly, but not heavily, marked with small spots of very dark browns, “warm sepia” to “bone brown,” or brownish black. There is a set of three eggs, which seems to be the usual number, in the collection of Col. John E. Thayer, taken at Omsk, Siberia, on June 9, 1893. These are subpyriform in shape, without gloss. The ground colors vary from “deep olive buff” to “pale olive buff.” One egg is uniformly covered with fine pen-like scrawls of “sepia” and “pale violet gray.” The others are marked, chiefly in a ring near the large end, with similar scrawls and with irregular spots of brownish black or black. The measurements of 15 eggs average 35.2 by 26.2 millimeters; the eggs showing the four extremes measure 37.5 by 27, 32 by 28.8 and 30.5 by 23.2 millimeters.

Mr. Jourdain says in his notes:

The 12 eggs taken by Osmaston (1927) averaged 36.7 by 26.3, while the 6 obtained by Whistler (1925) averaged 38.4 by 26.5 millimeters, thus agreeing well on the whole with those of the eastern race, but are as a rule rather larger. The coloration is also similar, speckled with dark brown spots on a ground of creamy stone.

The parent bird slips off the nest very quietly and returns very cautiously by short runs. It is naturally very difficult to follow in the great waste of sand and shingle. When disturbed on the breeding ground the old birds behave much as other sand plovers, flying round uneasily in circles and running about swiftly, but were less noisy than common or lesser ringed plovers.

Young.—Doctor Stejneger (1885) says that the young ones are found—

about the middle of July. About this time the families retire from the beach and are now met with in the interior, where they ascend the mountains in search of tender insects. I frequently met them at an altitude of 1,000 feet or more above sea level. About the middle of September the families return to the lowlands and to the beach, soon afterwards leaving the islands.

While at Glinka, on Copper Island, in July, 1883, a young bird of this species, not yet fully feathered, was brought to me alive. Allowed to run free on the floor it immediately commenced a very animated pursuit of the rather numerous flies, which were caught with remarkable precision and rapidity and devoured with an unsatiable appetite. The little fellow did not pay any attention to the presence of several persons in the small room, but when the dog rose from his nap in the corner, the swift-footed fly killer suddenly dropped flat on the floor, with withdrawn neck, making himself as small and flat as possible, and remained thus perfectly immovable until the dog turned his head the other way, then he ran off to the darkest corner of the room, where he remained until the former laid down in his old place. Then he started the fly hunting again; the dog rose once more, and the same performance was repeated. Within half an hour, however, he had learned that the dog did not take any notice of him whatever, and consequently he afterwards paid as little attention to the dog as to man.

Plumages.—The young bird referred to above was about half grown and largely feathered when it died, but the specimen shows a little of the natal down, mainly on the head, which is largely downy. The forehead is buffy white, the crown mostly dark “bister,” and the sides of the head are mottled with buffy and “bister”; the throat is pale buff. The remiges are half grown and the new feathers of the mantle are “sepia,” with “cinnamon-buff” tips; the feathers of the breast are “cinnamon buff” or “pinkish buff” and those of the belly are white.

Evidently the juvenal plumage soon fades, for a specimen taken on September 22, in full juvenal plumage, is much paler. The entire upper parts are “hair brown” or “drab,” with narrow, pale, buffy edgings; the forehead and under parts are white, but the breast is suffused with “pinkish buff” and invaded on the sides with the “drab” of the upper parts.

There is not sufficient material to show the molts and plumages satisfactorily. Adults have a complete molt in August and September, at which the cinnamon of the chest, neck, and head entirely disappears.

Voice.—Doctor Stejneger (1885) says that “the call note is a clear, penetrating drrrriit.” Mr. Jourdain adds: “The call note is described by Whistler as a soft twip, and the alarm note as a sort of chatter of two syllables corr up, not unlike the note of a frog and compared by Osmaston to that of a nightjar. It is uttered usually on the wing and also occasionally on the ground.”

DISTRIBUTION

Range.—Eastern Asia and Oceanica; accidental in Alaska.

Breeding range.—This race of the Mongolian plover breeds chiefly in northeastern Siberia (Cape Serdze, Bering Island, Kamchatka, and the Commander Islands); probably also in Dauria and Mongolia.

Winter range.—The winter range includes the Philippine Islands, the Moluccas, New Guinea, and northern Australia.

Migration.—The species has been noted to arrive in spring at Yokohama, Japan, on April 28, and at Bering Island, on May 11. A late fall date on Bering Island is September 22.

Casual records.—On June 11, 1925, an adult male was collected at Cape Prince of Wales (Bailey). Two specimens were taken by C. G. Harrold on Nunivak Island, Alaska, in 1927, one on August 14, and one on September 1; others were seen on August 14 and September 11 and 13. These are the only North American records.

Egg dates.—Bering Island, June 4. Siberia, June 9.