I doubt very much if this species is really distinct from Ninox mindorensis; the size is nearly the same and specimens of the two do not seem to have been actually compared.

Subfamily STRIGINÆ.
Genus STRIX Linnæus, 1758.[31]

Large; without ear-tufts; secondaries nearly as long as primaries; plumage compact; barred below, spotted above; legs and toes closely feathered.

231. STRIX WHITEHEADI (Sharpe).
PALAWAN BARRED OWL.

Palawan (Whitehead, Platen, Bourns & Worcester, Celestino).

“Adult male.—General color above chocolate-brown, spotted with white, the spots arranged in pairs, the one on the inner web often fulvescent; scapulars forming a light patch of tawny-buff, covered with narrow bars of chocolate-brown; lesser wing-coverts dark chocolate-brown, with scarcely any white spots; median and greater coverts more reddish chocolate-brown, transversely barred with white, slightly tinged with tawny-buff; alula and primary-coverts uniform blackish brown; quills brown, crossed with lighter and more rufous-brown bars, whiter near the edge, especially of the secondaries, which are slightly freckled externally; the innermost secondaries spotted with white, like the back; upper tail-coverts like the back, but barred with tawny-buff or whitish; tail-feathers dark chocolate-brown, barred with tawny-buff or creamy white, with which the tail is conspicuously tipped, the light bars, seven in number, on the center feathers, broader and coalescing on the remainder; crown of head like the back, thickly spotted with white, the spots arranged in pairs; feathers of the hind neck with concealed bases of tawny-buff; the mantle somewhat more uniform brown; sides of face chestnut, deeper about the eyes and on the ear-coverts, which are whiter posteriorly; ruff dark chocolate-brown, barred across with rufous; chin rufous, followed by a broad white patch, narrowly barred with black; remainder of under surface of body tawny-rufous, narrowly barred across with blackish brown including the thighs and under tail-coverts; fore neck with broad bands of white and chocolate-brown; under wing-coverts and axillars like the breast; quills below dusky brown, barred with yellowish buff, these bars broader toward the base of the inner web. Length, 444; wing, 330; tail, 190; culmen, 34; tarsus, 58.

“Of this fine owl Mr. Whitehead obtained several specimens. Its nearest ally is Syrnium sinense, but it is easily distinguished from that species by its rufescent under surface, with the absence of white bars.” (Sharpe.)