& i. Feet formed for grasping.
Bill strong, covered at the base with a cere, hooked towards the extremity: legs strong and muscular, short, or of moderate length: toes four in number, three directed forwards and one behind; rough underneath; armed with powerful, sharp, curved, retractile talons.
Head and neck more or less divested of feathers: nostrils lateral, placed in the cere, oval or elongated: feet generally naked: claws moderately curved.
Bill long, slender, straight, hooked at the extremity; lower mandible bending downward; no gonys: nostrils longitudinal, lateral, situate near the ridge: fore part of the head naked ; neck feathered: feet strong, moderate, naked: wings long; third quill the longest: tail of fourteen feathers.
Head feathered: nostrils la-- teral, placed in the cere, rounded or oval: legs feathered to the toes, or naked: claws strongly curved, very sharp.
Bill long, very robust, convex or slightly angular above, straight at the base, much hooked at the tip: cere hispid: nostrils rounded, or lunulate: wings long.
(1. Aquila). Tarsi feathered to the toes: claws unequal, grooved beneath: fourth quill longest.
(2. HaliAeetus). Tarsi half-feathered; acrotarsia scutellated: claws unequal, grooved beneath: fourth quill longest: nostrils transverse.
(3. Pandion). Tarsi naked; acrotarsia reticulated with small rounded scales: outer toe reversible: claws equal, rounded beneath : second quill longest.
Bill short, strong, bending from the base; upper mandible strongly toothed, lower one eraar-ginated: nostrils round: tarsi short and strong; acrotarsia reticulated: wings long; second quill longest; first and second with the inner webs deeply notched near the extremity.
Bill short, rather strong, bending from the base: nostrils oval: tarsi slender; acrotarsia scutellated: middle toe much longer than the lateral ones: wings short, not reaching beyond two-thirds of the length of the tail: fourth quill longest.
(1. Astur). Tarsi moderate; rather robust: acrotarsia scutellated.
(2. Accipiter). Tarsi long and slender: acrotarsia scutellated; the sutures of the scales obsolete.
Bill moderate, rather weak, bending slightly from the base, somewhat angular above: nostrils oblique, oval or elliptic: tarsi short: toes and claws weak : wings very long: tail long, and forked.
(1. Milvus). Tarsi feathered a little below the knee; acrotarsia scutellated: fourth quill longest.
(Elanus). Tarsi very short, half-feathered ; acrotarsia reticulated: second quill generally the longest.
Bill moderate, bending from the base : nostrils oval or roundish : tarsi partly naked, or clothed with feathers: wings long; third and fourth quills generally the longest; the four first emarginated on their inner webs: tail even.
(1. Buteo). Lore without feathers: tarsi short and strong; naked, with the acrotarsia scutellated; or feathered to the toes.
(2. Pernis). Lore closely covered with small scaly feathers: tarsi moderate, half-feathered; acrotarsia reticulated.
(3. Circus). Sides of the head furnished with a circle of feathers approaching that of the owls: tarsi elongated, feathered a little below the joint; acrotarsia scutellated: tail long; somewhat rounded.
Headlarge, feathered; base of the bill clothed with stiff bristly feathers directed forwards, concealing the cere and nostrils: eyes surrounded by a circle of radiating feathers: legs feathered to the toes: outer toe reversible.
Bill strong, bending from the base: nostrils oval or rounded: facial disk small and incomplete: auditory aperture small, oval, without an operculum: head furnished with large conspicuous egrets: wings moderate; third quill generally the longest.
Bill bending from the base: nostrils oval, oblique: facial disk complete, of moderate size: auditory eonch large, the aperture covered by an operculum: egrets more or less conspicuous: wings long; second quill longest: legs feathered to the claws.
Bill somewhat elongated, bending at the tip only : nostrils oval: facial disk complete and full-sized : auditory aperture large, furnished with an operculum: head without egrets: wings long; second quill longest: tarsi feathered : toes hairy ; middle claw serrated beneath.
Bill bending from the base: nostrils round: facial disk large and complete: auditory aperture large, furnished with an operculum: head without egrets: wings short and rounded; fourth and fifth quills longest: legs feathered to the claws.
Bill bending from the base: nostrils oval: facial disk small, and generally very incomd2 plete: auditory aperture small, oval: head without egrets: wings moderate; third quill longest.
(1. Surnia). Legs and toes thickly feathered.
(2. Noctua). Tarsi feathered: toes either feathered or hairy.