Slender-billed Kite Helicolestes hamatus Scientific name definitions

The Slender-billed Kite is a large, dark kite of swamp forest. It superficially resembles the sympatric Snail Kite (Rostrhamus sociabilis) in having overall dark gray plumage, red legs, a red bill base, and a sharply-hooked bill. Its entirely dark tail and underparts, relatively short wings and tail, and behavioral details distinguish this species from the Snail. Like the Snail Kite, it feeds largely on snails in the genus Pomacea, capturing them on flights down from a low perch and using its hooked bill to sever the snails attachment to its shell so that the snail can be extracted for consumption. Slender-billed Kites construct a stick nest in a tree over water.

35–41 cm (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ); male 377–448 g, female 367–485 g; wingspan 80–90 cm (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Chunky, with broad, round-tipped wings, short, square-tipped tail (hardly protruding behind wings in flight) and thin, well-hooked bill ; soars low above canopy (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Slate-grey , primaries and tail black; iris white to orange-yellow (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ), legs, cere and facial skin yellow-orange to orange-red (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Separated from male R. sociabilis by eye colour, dark rump, broader wings and much shorter tail. Sexes alike, with female only very marginally larger and heavier (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Juvenile similar, but tail has 2–3 white bars and white tip; buff or white edging to wing-coverts, secondaries and rump.

Extreme E Panama through N & E Colombia to W & NE Venezuela, Suriname and French Guiana; also S through Amazonian Brazil to E Peru and N Bolivia (Pando and Beni) (2 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ); limits of range poorly documented, in part owing to confusion with Rostrhamus sociabilis. An individual watched in Tocantins (Brazil) in 2001 (3 Olmos, F., Pacheco, J.F. and Silveira, L.F. (2006). Notas sobre aves de rapina (Cathartidae, Acciptridae e Falconidae) brasileiras. Rev. Bras. Orn. 14(4): 401–404. Close ).

Flooded forest margins, e.g. around shallow lagoons and drying flooded areas (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Rain forest, edges of swampy forest, especially várzea; also stagnant lagoons, and wooded plantations, up to 750 m (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ). Regularly soars in groups of up to 10 birds (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ), although not very high up.

No movements reported, but records in Panama (both in late 1950s) speculated to perhaps involve vagrants (4 Angehr, G. R., and R. Dean (2010). The Birds of Panama: A Field Guide. Cornell University Press, Ithaca, New York, USA. Close ).

Specializes on snails of genus Pomacea. Extracts snail from shell by piercing and severing its columellar muscle at point of attachment to shell. Usually hunts from a low perch . In one study, 8% of diet was freshwater crabs (Dilocarcinus dentatus).

Gives a mewing "weeeuuu" not unlike a buteo and a nasal, rising then falling "wheeeaaaaah" (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ).

Poorly known. In Venezuela and the Guianas, nests Jun–Oct (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ), during wet season; nest with eggs, early Jul in NE Peru (5 Begazo, A. J., and T. H. Valqui (1998). Birds of Pacaya-Samiria National Reserve with a new population (Myrmotherula longicauda) and new record for Peru (Hylophilus semicinereus). Bulletin of the British Ornithologists’ Club 118(3):159–166. Close ), and active nest (contents unknown), late Jul in E Ecuador (6 Greeney, H. F., R. A. Gelis, and R. White (2004). Notes on breeding birds from an Ecuadorian lowland forest. Bulletin of the British Ornithologists' Club 124:28–37. Close ). Nests about 1 km apart. Flimsy stick nest , on average 14 m high (but also at 18 m (5 Begazo, A. J., and T. H. Valqui (1998). Birds of Pacaya-Samiria National Reserve with a new population (Myrmotherula longicauda) and new record for Peru (Hylophilus semicinereus). Bulletin of the British Ornithologists’ Club 118(3):159–166. Close ), 20 m (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ) and c. 25 m (6 Greeney, H. F., R. A. Gelis, and R. White (2004). Notes on breeding birds from an Ecuadorian lowland forest. Bulletin of the British Ornithologists' Club 124:28–37. Close ) ) on slanting limbs or in crotch of tree, in flooded gallery forest or coffee plantation (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ); trimmed with fresh boughs by both adults. Pair-bond speculated to be life-long (7 Beissinger, S.R., Thomas, B.T. and Strahl, S.D. (1988). Vocalizations, food habits, and nesting biology of the Slender-billed Kite, with comparisons to the Snail Kite. Wilson Bull.. 100(4): 604-616. Close ). 2 eggs (possibly 3 (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ) ); incubation c. 30 days; chicks have brown down with some whitish markings; fledging 35 days, with birds flying at 40 days. Both sexes incubate, brood and feed young. No evidence of sequential polyandry or polygyny, as in R. sociabilis.

Not globally threatened (Least Concern). CITES II. Poorly known, and requires further study; in Venezuela range recently extended NW to L. Maracaibo basin (8 Sharpe, C. J., D. Ascanio-Echeverría, and G. A. Rodríguez (2001). Further range extensions and noteworthy records for Venezuelan birds. Bulletin of the British Ornithologists’ Club 121(1):50–62. Close ). Restriction to gallery forest and flooded forest may make species very susceptible to effects of deforestation, although has been recorded nesting in plantations (1 Ferguson-Lees, J., and D. A. Christie (2001). Raptors of the World. Christopher Helm, London, UK. Close ); highly specialized diet.