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Rostrhamus sociabilisEverglade kite(Also: snail kite)

By Kim Tyson

Geographic Range

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)

Habitat

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.

  • Aquatic Biomes
  • lakes and ponds

Physical Description

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
    11.98 to 19.98 oz

Reproduction

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.

  • Average eggs per season
    3
    AnAge
  • Average time to hatching
    30 days
    AnAge

Lifespan/Longevity

Behavior

Voice: The bird protects its nest by making a cackling cry (kor-ee-ee-a, kor-ee-ee-a). Its cries are very low and can only be heard locally. During courtship, it cries by making an almost sheep-like noise.

Flight: The bird's flight is a lot less graceful than other birds. It almost appears like a heron. This is due to the fact that the bird has large, broad wings, yet a very slender, weak body. They are often seen perching on fence posts, telephone oles, and telegragh wires. They fly over marshes by beating their wings slowly, while looking for apple snails at a height of 25 to 100 feet.

Socially: They are often very social when roosting. Groups often fly for several miles together with the goal to roost. They roost in leafless bushes (surrounded by water) in groups of fifteen or twenty. They congregate around dusk. Together, they rest and preen.

Communication and Perception

Food Habits

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.

Economic Importance for Humans: Positive

The Snail Kite has little effect on humans.

Economic Importance for Humans: Negative

The snail kite has little effect on humans.

Conservation Status

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.

Contributors

Kim Tyson (author), Cocoa Beach High School, Penny Mcdonald (editor), Cocoa Beach High School.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Sykes, P. 1979. Status of the Everglade Kite in Florida. Wilson Bulletin, 91: 494-511.

U. S. Fish and Wildlife Service, 1991. "Everglade Snail Kite" (On-line). Accessed February 21, 2000 at http://endangered.fws.gov/i/b/sab0v.html.

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