Key to Scientific Names in Ornithology
(Accipitridae; Ϯ Slender-billed Kite H. hamatus) Gr. ἑλιξ helix, ἑλικος helikos spiral, snail shell; λῃστης lēistēs robber < λῃστευω lēisteuō to rob; "The generic name Rostrhamus Lesson (Traité d'orn., 1830, p. 55), type Rostrhamus niger Lesson, judging from the descriptions of both the adult male and young, applies wholly to the bird now known as Rostrhamus sociabilis (Vieill.). Lesson refers also to Falco hamatus Illiger, Temm., Pl. col., but draws his description from specimens in hand, and not from the plates. Plate 61 represents the adult of the species now known as R. hamatus, showing clearly the short tail and short wing-tip, which we consider generically distinct. But Plate 231 depicts the young of R. sociabilis with the characteristic long wing-tip and white upper and under tail-coverts. Hamirostrum Sundevall (Avium disp. tent., 1873, p. 109), is simply a substitute for Rostrhamus Lesson; see A.O.U. Code 1908, Canon XXX, p. lix. HELICOLESTES, gen. nov. Type.— Falco hamatus Illiger, Temm. Pl. col., 1823, 1, pl. 61. Characters.— Similar to Rostrhamus Lesson, but with a very short wing-tip, the primaries exceeding the secondaries by not over 50 mm.; tail very short, about 120 mm.; immature plumage slate-gray, not essentially different from adult, except in white barring of tail and primaries." (Bangs & Penard 1918). Freshwater snails constitute the exclusive prey of the Slender-billed Kite.