About Rostrhamus sociabilis (Vieillot, 1817)
Snail kites (Rostrhamus sociabilis) measure 36 to 48 cm (14 to 19 in) in length, with a wingspan of 99 to 120 cm (39 to 47 in), and weigh between 300 and 570 g (11 to 20 oz). Sexual dimorphism in this species is very limited, with females averaging only 3% larger than males. Each of their long, broad, rounded wings measures 29 to 33 cm (11 to 13 in). They have a long tail, between 16 and 21 cm (6.3 to 8.3 in) long, plus a white rump and white undertail coverts. Their dark, deeply hooked beak, which measures 2.9 to 4 cm (1.1 to 1.6 in), is an adaptation adapted to their diet. They also have a relatively long tarsus, that measures between 3.6 and 5.7 cm (1.4 to 2.2 in). Adult male snail kites have dark blue-gray plumage, with darker flight feathers, and red legs and cere. Adult females have dark brown upperparts and heavily streaked pale underparts, a whitish face with darker patches behind and above the eye, and yellow or orange legs and cere. Juvenile snail kites are similar in appearance to adult females, but have streaked crowns. Adult snail kites have red or orangish-brown irises, while juveniles have dark brown irises. This species flies slowly with its head pointed downward, searching for its main food source: large apple snails. Because of this diet, the snail kite is classified as a molluscivore. The snail kite breeds in tropical South America, the Caribbean, and central and southern Florida in the United States. It is a year-round resident across most of its range. However, the southernmost populations of snail kite migrate north for the winter, and birds from the Caribbean populations disperse widely outside of the breeding season.
