The Snail Kite, Rostrhamus sociabilis, is a bird of prey within the family Accipitridae, which also includes the eagles, hawks and Old World vultures. Its relative, the Slender-billed Kite, is now again placed in Helicolestes, making the genus Rostrhamus monotypic. Usually placed in the milvine kites, the validity of that group is under investigation.
Snail Kites are 45cm long with a 120cm wingspan. They have long, broad, and rounded wings. It is long-tailed, with a white rump and undertail coverts. The dark, deeply hooked beak is an adaptation to its diet.
The adult male has dark blue-gray plumage with darker flight feathers. The legs and cere are red. The adult female has dark brown upperparts and heavily streaked pale underparts. She has a whitish face with darker areas behind and above the eye. The legs and cere are yellow or orange. The immature is similar to adult female, but the crown is streaked.
The flight is slow, with the kite's head facing downwards as it looks for large apple snails, its main food.
Distribution and ecology
The Snail Kite breeds in tropical South America, the Caribbean and central and southern Florida, USA. It is resident all-year in most of its range, but the southernmost population migrates north in winter and the Caribbean birds disperse widely outside the breeding season.
The Snail Kite is a locally endangered species in the Florida Everglades, with a population of less than 400 breeding pairs. Research has demonstrated that water-level control in the Everglades is depleting the population of apple snails. However, this species is not generally threatened over its extensive range.
In fact, it might be locally increasing in numbers, such as in Central America. In El Salvador, it was first recorded in 1996. Since then, it has been regularly sighted, including immature birds, suggesting a resident breeding population might already exist in that country. On the other hand, most records are outside the breeding season, more indicative of post-breeding dispersal. In El Salvador, the species can be observed during the winter months at Embalse Cerrón Grande, Laguna El Jocotal and especially Lago de Güija. Pomacea flagellata apple snails were propagated in El Salvador between 1982 and 1986 as food for fish stocks, and it seems that the widespread presence of high numbers of these snails has not gone unnoticed by the Snail Kite.
This is a gregarious bird of freshwater wetlands, forming large winter roosts. Its diet consists almost exclusively of apple snails.
On May 17 2007, a birdwatcher photographed a Snail Kite feeding at a crawfish farm about 35 southeast of Columbia, South Carolina. The discovery, if confirmed by the South Carolina Bird Records Committee, may lead to testing of crawfish as an alternative food for the bird.
It nests in a bush or on the ground, laying 3-4 eggs.