"Adult male.--Chin, throat, and upper part of fore neck mottled with white; a narrow white line, about 125 mm. long, commencing above gape and continued down sides of neck; head and neck brown, darker and slightly glossed on the crown and along the back of the neck, paler down the middle of fore neck, each feather being margined with pale brown and giving the whole a finely scaled appearance; upper back brownish black, each feather narrowly margined with rufescent and streaked with white on the lateral parts; rest of back, rump, lower part of fore neck, and under parts black with an oil-green gloss; wing-coverts, scapulars, and innermost secondaries black, each with a long, silvery white streak down the middle; scapulars much elongated and pointed, the longest measuring about 230 mm.; innermost secondary transversely ribbed along the basal two-thirds of outer web; quills and tail black, the middle pair of tail-feathers strongly ribbed on outer web and outer pairs slightly rayed. Tail composed of twelve feathers. 'Iris yellow; bill dusky on culmen, yellowish on sides and on lower mandible; legs black.' (Godwin-Austen.) Length, about 890; culmen, from feathers on forehead, 89 to 91; wing, 330 to 355; tail, 218 to 230; tarsus, 43; outer toe with claw, 81. "The fully adult female (if the sex of several specimens in the British Museum is correctly determined) appears to be perfectly similar in plumage to the male, the only difference being that the bill is decidedly shorter, 79 to 81 mm. In some females, however, which appear to be perfectly adult, the black bases of the fore neck and the chest are divided on either side from the back by a whitish buff band, as in immature birds. "Immature birds.--General color as in the adult, but neck much lighter and of a pale brownish white, becoming white down the middle of the fore neck; black at base of fore neck and chest bordered on each side by a whitish buff band; streaks on the upper plumage of a more yellowish white, long pointed scapulars absent or half developed; quills and tail-feathers pointed and narrowly margined at the tips with pale whitish brown; ribs on innermost scapulars and tail-feathers but slightly indicated; back, rump, and upper tail-coverts brownish black. "Young in down.--Head, neck, upper back, and under parts covered with white down, amongst which the plumage of the immature is more or less visible; quill- and tail-feathers half grown, pointed and narrowly margined at the extremity with pale brownish white; scapulars and wing-coverts much like those of the adult, but fringed externally with brown. Length, 724." (Grant.) "Exceedingly abundant about Lake Naujan in Mindoro, where it breeds. Rarer about fresh-water streams in the interior of that island. Not met with by us outside of Mindoro.