"Abundant about fish-breeding ponds in tide-water marshes of Bulacan in February, 1904. Also at Anao, Tarlac Province, in same month and year. Fairly common in the Candaba swamp, Luzon." (Worcester.) Order ACCIPITRIFORMES. EAGLES, HAWKS, AND FALCONS. Bill strong, upper mandible considerably longer than the lower, culmen much curved, end of bill hooked and its tip perpendicular; basal portion of bill covered by a membrane or cere, in which the nostrils are situated; legs large; feet very strong, claws curved and sharp; general plumage compact; wings long and powerful; tail nearly square, rarely forked or wedge-shaped. Suborders. a1. Claws less curved, that of middle toe describing much less than a semicircle; outer toe not reversible. ... Accipitres (p. 211) a2. Claws greatly curved, that of middle toe describing a full semicircle; outer toe reversible. ... Pandiones (p. 244) Suborder ACCIPITRES. This suborder includes all the hawks and eagles except the fish hawks of the genera Pandion and Polioaëtus; its members are distinguished by having the outer toe not reversible and all of the claws moderately curved, that of middle toe describing much less than a semicircle; concave or under side of each claw hollowed or grooved instead of rounded. Family FALCONIDÆ. Characters same as those given for the Suborder. Subfamilies. a1. Tarsus and toes longer and more slender. ... Accipitrinæ (p. 211) a2. Tarsus and toes shorter and stouter. ... Aquilinæ (p. 222) Subfamily ACCIPITRINÆ. In external characters this subfamily differs very little from Aquilinæ; its members are weaker with body and legs more slender, wings and tail longer, and plumage less compact. Genera. a1. Hinder aspect of tarsus with many hexagonal scales; wing, 300 mm. or more. ... Circus (p. 211) a2. Hinder aspect of tarsus without hexagonal scales; wing, 200 mm. or less. b1. Middle toe without claw about twice the culmen from anterior margin of cere. ... Astur (p. 216) b2. Middle toe without claw more than twice the culmen from anterior margin of cere. ... Accipiter (p. 219) Genus CIRCUS Lacépède, 1799. Bill moderate or weak, somewhat compressed; margin of upper mandible slightly sinuate but not toothed; wing very long and pointed, first primary short, about equal to sixth; secondaries much shorter than primaries; tail long, slightly graduated or nearly square; tarsus long and slender, feathered at the base and overhung for about half its length by the long thigh-feathers; front of tarsus with transverse plates, sides and most of the hinder aspect with hexagonal scales; toes long, nails long and much curved; behind ear-coverts and sometimes across the throat a "ruff" of short, rather stiff feathers, most conspicuous in the young of melanoleucos and not very evident in the other species.