The snail kite (''Rostrhamus sociabilis'') is a
bird of prey
Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predators h ...
within the family
Accipitridae
The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-s ...
, which also includes the
eagle
Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. Most of the 68 species of eagle are from Eurasia and Africa. Outside this area, just ...
s,
hawk
Hawks are bird of prey, birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica.
* The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. Th ...
s, and
Old World vulture
Old World vultures are vultures that are found in the Old World, i.e. the continents of Europe, Asia and Africa, and which belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.
Old World vultures are not clos ...
s. Its relative, the
slender-billed kite
The slender-billed kite (''Helicolestes hamatus'') is a South American bird of prey in the family Accipitridae. It is found along a scattered range in forested parts of tropical northern and central South America, and far eastern Panama. The spec ...
, is now again placed in ''Helicolestes'', making the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''Rostrhamus''
monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...
. Usually, it is placed in the
milvine kites, but the validity of that grouping is under investigation.
Description
![Rostrhamus sociabilis 110977267 cropped](https://upload.wikimedia.org/wikipedia/commons/9/90/Rostrhamus_sociabilis_110977267_cropped.jpg)
Snail kites are long with a wingspan. They weigh from .
[ 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 each. Its tail is long, at , with a white rump and undertail coverts. The dark, deeply hooked beak, measuring is an adaptation to its diet. The tarsus is relatively long as well, measuring .][
The adult male has dark blue-gray ]plumage
Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...
with darker flight feather
Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tail ...
s. The legs and cere
The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and a few mammals. A beak is used for eating, preening, manipulating objects, killing prey, fighting, probing for food, ...
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.
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 A molluscivore is a carnivorous animal that specialises in feeding on molluscs such as gastropods, bivalves, brachiopods and cephalopods. Known molluscivores include numerous predatory (and often cannibalistic) molluscs, (e.g.octopuses, murexes, de ...
.
Taxonomy
Lerner and Mindell (2005) found ''R. sociabilis'' sister to ''Geranospiza caerulescens
The crane hawk (''Geranospiza caerulescens'') is a species of bird of prey in the family Accipitridae. It is monotypic within the genus ''Geranospiza''.
Taxonomy
The crane hawk used to be many species that were recently lumped into one. Those ...
'', and that those two along with '' Ictinea plumbea'' were basal to both the ''Buteogallus
''Buteogallus'' is a genus of birds of prey in the family Accipitridae. All members of this genus are essentially neotropical, but the distribution of a single species extends slightly into the extreme southwestern United States. Many of the sp ...
'' and ''Buteo
''Buteo'' is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but "hawk" is used in the New World (Etymology: ''Buteo'' is the Latin name o ...
'' clades. They concluded that ''Rostrhamus'' belonged in Buteoninae
The Buteoninae are a subfamily of birds of prey which consists of medium to large, broad-winged species.
They have large, powerful, hooked beaks for tearing flesh from their prey, strong legs, and powerful talons. They also have extremely keen e ...
(sensu stricto) and not in Milvinae
The Milvinae kites are found in the family Accipitridae
The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds with strongly hooked bills and variable morphology based on diet. ...
, but noted that more investigation was needed.[
]
Distribution
The snail kite breeds in tropical South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, the Caribbean
The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Se ...
, and central and southern Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. 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.
Breeding
It nests in a bush
Bush commonly refers to:
* Shrub, a small or medium woody plant
Bush, Bushes, or the bush may also refer to:
People
* Bush (surname), including any of several people with that name
**Bush family, a prominent American family that includes:
*** ...
or on the ground, laying three to four eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
.
Conservation
The snail kite is a locally endangered species in the Florida Everglades
The Everglades is a natural region of tropical climate, tropical wetlands in the southern portion of the U.S. state of Florida, comprising the southern half of a large drainage basin within the Neotropical realm. The system begins near Orland ...
, 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
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
is not generally threatened over its extensive range.
In fact, it might be locally increasing in numbers, such as in Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
. In El Salvador
El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south b ...
, 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
Laguna (Italian and Spanish for lagoon) may refer to:
People
* Abe Laguna (born 1992), American DJ known as Ookay
* Andrés Laguna (1499–1559), Spanish physician, pharmacologist, and botanist
* Ana Laguna (born 1955), Spanish-Swedish ballet da ...
, 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.
Diet
This is a gregarious bird of freshwater wetland
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
s, forming large winter roosts. Its diet consists almost exclusively of apple snails, (especially the species ''Pomacea paludosa
''Pomacea paludosa'', common name the Florida applesnail, is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Ampullariidae, the apple snails.
Shell description
This species is the largest freshwa ...
'' in Florida).
Snail kites have been observed eating other prey items in Florida, including crayfish
Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...
in the genus ''Procambarus
''Procambarus'' is a genus of crayfish in the family Cambaridae, all native to North and Central America. It includes a number of troglobitic species, and the marbled crayfish (''marmorkrebs''), which is parthenogenetic. Originally described as a ...
'', crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...
s, black crappie
The black crappie (''Pomoxis nigromaculatus'') is a freshwater fish found in North America, one of the two types of crappies. It is very similar to the white crappie in size, shape, and habits, except that it is darker, with a pattern of black sp ...
, small turtle
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...
s and rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...
s. 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 birdwatcher photographed a snail kite feeding at a red swamp crayfish farm in ]Clarendon County, South Carolina
Clarendon County is a county located below the fall line in the Coastal Plain region of U.S. state of South Carolina. As of 2020 census, its population was 31,144. Its county seat is Manning.
This area was developed for lumber and mills, incl ...
.[
The presence of the large introduced '']Pomacea maculata
''Pomacea maculata'' is a species of large freshwater snail with an operculum, an aquatic gastropod mollusk in the family Ampullariidae, the apple snails.
Common name of its synonymous name ''Pomacea insularum'' is the island applesnail.
Toge ...
'' 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
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
. These non-native snails provide a better food source over the smaller native snails and has had a positive effect on their populations.
References
External links
Snail Kite Information
a
Great Florida Birding & Wildlife Trail
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{{Taxonbar, from=Q839657
snail kite
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 ...
snail kite
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 ...
Birds of Cuba
Birds of El Salvador
Birds of Mexico
Birds of South America
Native birds of the Southeastern United States
Birds of the Yucatán Peninsula
Higher-level bird taxa restricted to the Neotropics
snail kite
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 ...
snail kite
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 ...