328 MANUAL OF PHILIPPINE BIRDS. 
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 tii 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. 
290. HYDROCORAX MINDANENSIS (Tweeddale). 
MINDANAO CALAO. 
Buceros mindanensis TWEEDDALE, Proc. Zool. Soe. (1877), 543; Challenger 
Report, Zool. (1881), 2, pt. 8, pl. 3. 
Hydrocorax mindanensis GRANT, Cat. Birds Brit. Mus. (1892), 17, 359; 
SHARPE, Hand-List (1900), 2, 64; McGrrecor and WorcEsTER, Hand- 
List (1906), 55. 
Basilan (Everett, Steere Exp., Bourns & Worcester, McGregor); Mindanao 
(Murray, Everett, Koch & Schadenberg, Steere Exp., Bourns & Worcester, Good- 
fellow, Celestino). 
Adult.—Plumage as in H. hydrocorax but casque much narrower and 
bill with distal two-thirds white. “Naked skin round eye sooty black, 
yellow just before the eye, gular skin yellow; iris light yellow (light 
green in living bird); feet coral-red; nails dark brownish gray.” 
(Everett.) Length of male, about 915; wing, 390; tail, 300; bill from 
nostril, 155; greatest length of casque, 136; greatest width of casque, 42; 
tarsus, 52. Length of female, 863; wing, 365; tail, 290; bill from 
nostril, 136; greatest length of casque, 124; greatest width of casque, 
59; tarsus, 48. 
“Young.—Upper part of head and cheeks black; feathers on chin and 
breast white, blackish gray at base; rest of head, neck, rump, belly, flanks, 
and tail-coverts white mixed with rufous; back, upper wing-coverts, 
scapulars, and outer secondaries brown, the three latter widely tipped, 
