Immature male.—Upper parts earthy brown, lighter on crown, the feathers tipped with white; forehead all white; long crest-feathers blackish brown; a black patch in front of and over eye; wing-coverts like the back; primaries and secondaries blackish brown, tipped with white; tail blackish brown, tipped with white and crossed by about nine lighter bars; entire under parts, except a brown patch on each flank, pure white. Wing, 370; tail, 225; culmen from base, 35; tarsus, 69; middle toe with claw, 72.

The sexes are similar in color. A male from Sibuyan measures: Wing, 340; tail, 190; culmen from base, 34; tarsus, 72. A female from northern Mindanao measures: Wing, 360; tail, 210; culmen from base, 35; tarsus, 66.

Genus SPIZAËTUS Vieillot, 1816.

Bill compressed; culmen rapidly curved from base to tip; edge of upper mandible sinuate; nostril large and oval; occipital crest short and slightly pointed; wings moderate, fourth or fifth quill longest; secondaries long, falling short of primaries by about length of middle toe without claw; tarsus covered to the toes with short thick-set feathers; top of toes covered with small irregular scales.

Species.
183. SPIZAËTUS PHILIPPENSIS Gurney.
PHILIPPINE HAWK EAGLE.

Basilan (Steere Exp., Bourns & Worcester); Luzon (Gevers, Heriot, Whitehead); Masbate (Steere Exp.); Mindoro (Porter); Negros (Everett, Steere Exp.); Palawan (Platen); Siquijor (Bourns & Worcester).