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, it is placed in the milvine kites, but the validity of that grouping is under investigation.
The snail kite breeds in tropical South America, the Caribbean, and central and southern Florida in the United States. It is resident all-year round in most of its range, but the southernmost population migrates north in winter and the Caribbean birds disperse widely outside the breeding season.
It nests in a bush or on the ground, laying three to four eggs.
This is a gregarious bird of freshwater wetlands, forming large winter roosts. Its diet consists almost exclusively of apple snails, especially the species Pomacea paludosa in Florida, and species of the genus Marisa.
Snail kites have been observed eating other prey items in Florida, including crayfish in the genus Procambarus, crabs in the genus Dilocarcinus, black crappie, small turtles and rodents. It is believed that snail kites turn to these alternatives only when apple snails become scarce, such as during drought, but further study is needed. On 14 May 2007, a birder photographed a snail kite feeding at a red swamp crayfish farm in Clarendon County, South Carolina.
The presence of the large introduced Pomacea maculata in Florida has led the snail kites in North America to develop larger bodies and beaks to better eat the snail, a case of rapid evolution. These non-native snails provide a better food source than the smaller native snails and have had a positive effect on the kites' populations.
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