Charadrius mongolus Pallas, Reise Russ. Reichs (1776), 3, 700.
Ochthodromus mongolus Sharpe, Cat. Birds Brit. Mus. (1896), 24,
223; Hand-List (1899), 1, 153; McGregor and Worcester, Hand-List
(1906), 23.
Ægialitis mongolica Grant, Ibis (1896), 126.
Basilan (McGregor); Batan (McGregor); Bohol (Everett); Cagayancillo
(McGregor); Calayan (McGregor); Cebu (McGregor); Cuyo (McGregor);
Leyte (Everett); Lubang (McGregor); Luzon (Whitehead, McGregor);
Mindanao (Mearns); Mindoro (Porter); Negros (Bourns & Worcester);
Palawan (Platen, Whitehead); Ticao (McGregor). Northern Asia,
south in winter to China, Malay Archipelago, and Australia.
"Adult in breeding plumage.--Similar to O. geoffroyi, but smaller,
bill and tarsus much shorter; a broader black line along sides
of face; ear-coverts entirely black; the white throat separated
from the rufous chest-band by a narrowly indicated line of
black. 'Bill black; feet somewhat bluish black, toes darker; iris
dark brown.' (Stejneger.) Length, 190; culmen, 19; wing, 127; tail,
53; tarsus, 30.
"Adult female in summer plumage.--Similar to the male, but less richly
colored; rufous chest-band never so pronounced; facial markings less
developed, the black bands on the forehead often obsolete. 'Bill
black; feet dark gray, with an olive tinge; toes darker, blackish;
iris dark hazel.' (Stejneger.) Length, 178; culmen, 20; wing, 140;
tail; 47; tarsus, 30.
"Adult in winter plumage.--Differs from the summer plumage in wanting
the facial markings and the rufous chest. Very similar to the winter
plumage of O. geoffroyi, and distinguished chiefly by its smaller
size, shorter bill, and shorter tarsus; there is also a little more
brown on the ear-coverts.
"Young.--Similar to the adults in winter plumage, but darker brown,
all the feathers edged with sandy brown; eyebrow, sides of face,
and under surface of body with a strong tint of sandy buff. 'Bill,
angle of mouth, and ring round eyes black; legs clear gray; tarsus
tinged with yellowish, toes with blackish, and soles with reddish;
iris dark brown.' (Stejneger.)
"The exact method by which the rufous chest of the summer plumage is
gained is not easy to discover. In some specimens in winter dress there
is a distinct narrow line of brown across the fore neck; in most of the
series of skins in the Museum this is wanting, as it is also in young
birds. It may therefore be a sign of very old birds only, as there are
traces of brown feathers in an old bird which has not quite attained
its full summer plumage. In the specimen in question it is also evident
that the rufous breast is being acquired by a change of color in the
feather, from brown to rufous, as well as by a molt. Probably only
very old birds go through this double process, as in the majority of
specimens the rufous breast appears to be gained by a molt only. When
first developed all the rufous feathers are edged with white.
"A young bird is described by Dr. Stejneger as somewhat resembling
the adult: 'The brownish gray of the back is paler, and each feather
narrowly edged with isabella-color, with which also the lower parts
are suffused. On the pectoral region a buffish tinge replaces the
rufous collar, and the black markings are absent from the head, the
cheeks and ear-coverts being slightly dusky; the forehead between
the bill and the eyes whitish, suffused with isabella-color.'
"The winter plumage and young livery of the western and eastern
forms of O. mongolus are, as might have been expected, very difficult
to distinguish, but the western form seems always to have a longer
tarsus (about 32 mm.), whereas the eastern form has the tarsus about
28 mm." (Sharpe.)