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.