Perception Channels: visual ; tactile ; acoustic ; chemical
The snail kite is considered threated because of the loss of their habitat. Widespread drainage as caused the water table to be lowered permanantly. This drainage has increased the areas available for development, in particular, the habitats of snail kites. Also, they are threated by a large infestation of water hyacinth (Eichornia crassipes). These plants are very dense and form on top of the water's surface. As a result, the snail kites are unable to identify apple snails. This results in a lower feeding area, and therefore the snail kites are unable to feed regularly. Also, pesticides and nutrient-runoff from nearby areas (particularly from contruction) have affected the snail kite's habitat. This has caused a distruption in their environment. Finally, there have been cases of humans shooting the snail kites. Together, the snail kites have decreased in population. It was first designated as endangered March 11, 1967 by the Federal Registrar.
US Federal List: endangered
IUCN Red List of Threatened Species: least concern
The snail kite has little effect on humans.
The Snail Kite has little effect on humans.
Traditionally the snail kites feed on apple snails (Pomacea paludosa) found in fresh water. The apple snails are about an inch and half across. Sometimes they will also hunt small turtles, however this is only when apple snails are scarce due to natural disasters. The snail kites catch prey by hunting while in the air, slowly and close to the ground. They swoop at about twenty feet in the air. They then drop down and pull the snails from the water. They swoop down with one foot, sometimes are forced to place as much as its belly into the water. However, it always tries to avoid getting as wet as possible, especially its tails. It carries the apple snail away with its sharp, long claws. The snail kite often misses its prey, however it is accustomed to many attempts in order to sustain itself. It gets the snail from the shell using its curved bill which is slender in size, while perching on one foot. The other foot holds the snail.
Snail Kites can be found in both South and Central America. Some are also found in Mexico and Cuba. The US also has small population concentrated in Florida (Panhandle, St. Johns Marshes, Lake Okeechobee, and the Everglades)
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Snail kites reside near freshwater lakes, marshes, and other bodies of water. They usually live where there is a large body of water (in order to see apple snails) with young, small vegetation (sawgrass and spikerushes). Particularly, they inhabit areas which contain apple snails (sloughts and flats). Also, the areas must contain scattered shrubs and trees in order for the hawks to make nesting sites. The birds often migrate from one area to another.
Terrestrial Biomes: savanna or grassland
Aquatic Biomes: lakes and ponds
Average lifespan
Status: wild: 176 months.
Snail Kites are medium-sized hawks, weighing from 12-20 ounces. They are about 14-16 inches long and have a wingspan of 43-36 inches. The females are very slightly smaller than the male (weight and length). They are sexually dimorphic in color. Males are traditionally slate gray with brown on the upper wing, with orange legs. Females are brown with white streaks (on face, chest, throat) and yellowish legs. Both male and female snail kites have red eyes, squarely tipped tail (dark in color) with a white base, and a slender, curved, hookied bill (black). When they are young, the birds resemble females.
Range mass: 340 to 567 g.
Other Physical Features: endothermic ; bilateral symmetry
Traditionally, snail kites have a mating season from February until June. The mating season varies due to weather conditions. However, it isn't uncommon for them to mate all other times during the year as well. The courtship process includes a variety of aerobatics and stick-carrying displays. The males perform short ascents and descents through the air, while beating their wings slowly. After this, the females invite the males to bring her food and other necessities (particularly for building a nest). The nests are usually formed in a colony (with individual nests being rarely constructed) of loose, bulky material. The nests are traditionally about thirteen inches in diameter and about 3 to 10 feet above the water (trees, shrubs). 2-4 eggs are usually laid and can be white, brown, or spotted. The eggs must be kept warm (incubated) for 27 or 28 days. Both parents participate in the incubation process of the eggs, as well as raising the newborns. Parents feed their children for about 2 months. It is also common for snail kites to have multiple mating partners.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average time to hatching: 30 days.
Average eggs per season: 3.
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.
Snail kites are 36 to 48 cm (14 to 19 in) long with a 99–120 cm (39–47 in) wingspan. They weigh from 300 to 570 g (11 to 20 oz).[3][4] There is very limited sexual dimorphism, with the female averaging only 3% larger than the male. They have long, broad, and rounded wings, which measure 29–33 cm (11–13 in) each. Its tail is long, at 16–21 cm (6.3–8.3 in), with a white rump and undertail coverts. The dark, deeply hooked beak, measuring 2.9–4 cm (1.1–1.6 in) is an adaptation to its diet. The tarsus is relatively long as well, measuring 3.6–5.7 cm (1.4–2.2 in).[4]
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 juvenile is similar to an adult female, but the crown is streaked. Adults have red or orangish-brown irises, while juveniles have dark brown irises.[5]
It flies slowly with its head facing downwards, looking for its main food, the large apple snails. For this reason, it is considered a molluscivore.
Lerner and Mindell (2005) found R. sociabilis sister to Geranospiza caerulescens, and that those two along with Ictinea plumbea were basal to both the Buteogallus and Buteo clades. They concluded that Rostrhamus belonged in Buteoninae (sensu stricto) and not in Milvinae, but noted that more investigation was needed.[6]
The snail kite breeds in tropical South America, the Caribbean, and central and southern Florida in the United States. 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.
It nests in a bush or on the ground, laying three to four eggs.
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.[7] 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.[8]
Due to the drainage and habitat destruction of the Everglades, they were one of the first species put on the US Fish and Wildlife Service's endangered species list[9] on 11 March 1967.[10] The snail kite continued to decline, reaching a population of less than 800 in 2007. Their population gradually rebounded after the invasive snail species Pomacea maculata began to flourish in the Everglades wetlands and served as a new food source for the snail kites, reaching a count of 3,000 snail kites in 2022. Everglades conservation efforts over the course of 30 years and costing over 20 billion USD also contributed to restoring the snail kites' habitats' native vegetation and flow of water in marshes.[9]
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.[11][12]
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.[13][14][15] It is believed that snail kites turn to these alternatives only when apple snails become scarce, such as during drought,[16] 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.[17][18]
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.[19] These non-native snails provide a better food source than the smaller native snails and have had a positive effect on the kites' populations.[20]
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.
