Buceros hydrocorax Linnæus, Syst. Nat. ed. 12 (1766), 1, 153.
Hydrocorax hydrocorax Grant, Cat. Birds Brit. Mus. (1892), 17,
358; Sharpe, Hand-List (1900), 2, 64; McGregor and Worcester,
Hand-List (1906), 55.
Ca-lao, Manila; reloj del monte, Spanish name.
Luzon (Meyer, Möllendorff, Everett, Steere Exp., Whitehead,
McGregor); Marinduque (Steere Exp.).
Adult.--Chin, upper throat, a band from throat to eye, and feathers
above eye, all black, followed on throat by a white space which shades
gradually into the dull chestnut-brown of lower throat and sides of
neck and head; breast and sides black; abdomen, thighs, and crissum
dull chestnut; back, rump, and wings brown, the rump lighter; primaries
and most of the secondaries black, some of the latter edged with pale
buff; tail-feathers pure white when fresh but soon becoming yellow or
dirty buff. Entire casque and bill bright red. "Naked skin round eye
yellow; iris red; feet brownish red; nails black." (Everett.) Length of
male, about 950; wing, 410; tail, 350; bill from nostril, 160; greatest
length of casque, 160; greatest width of casque, 52; tarsus, 60.
"Adult female.--Similar to the male. Length, 914; wing, 381; tail,
295; tarsus, 56.
"Young.--Cheeks and upper parts of head blackish; rest of head and
neck, rump, thighs, crissum, and under tail-coverts yellowish white
mixed with rufous; breast and belly yellowish white mixed with blackish
gray; back, wing-coverts, scapulars, and outer secondaries reddish
brown, the wing-coverts tipped and the scapulars and secondaries
margined with buff; primaries and rest of secondaries brownish black,
margined on the outer web and tipped with buff; basal two-thirds
of tail-feathers reddish brown, margined in all except the middle
pair with black. Bill and casque dark black, except the base of
the lower mandible and the extreme tip of the bill, which are
blood-red." (Grant.)
The three Philippine species of Hydrocorax do not differ in colors
but they are easily distinguished by the color and shape of the bill
and its casque. These large hornbills frequent forest, where they feed
on fruits, usually in high trees. Their call is loud and penetrating
and may be heard at a great distance. Their flight is rather labored
and produces a great noise.