Limpkin
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The limpkin (Aramus guarauna), also called carrao, courlan, and crying bird, is a large wading bird related to rails and cranes, and the only extant species in the family Aramidae. It is found mostly in wetlands in warm parts of the Americas, from Florida to northern Argentina, but has been spotted as far north as Wisconsin<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and Southern Ontario.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It feeds on molluscs, with the diet dominated by apple snails of the genus Pomacea. Its name derives from its seeming limp when it walks.<ref name=NatGeo/>
Taxonomy and systematicsEdit
The limpkin is placed in the family Aramidae, which is in turn placed within the crane and rail order Gruiformes.<ref name="hbwfamily"/> The limpkin had been suggested to be close to the ibis and spoonbill family Threskiornithidae, based upon shared bird lice. The Sibley–Ahlquist taxonomy of birds, based upon DNA–DNA hybridization, suggested that the limpkin's closest relatives were the Heliornithidae finfoots, and Sibley and Monroe even placed the species in that family in 1990.<ref name=SibleyCG1990/> More recent studies have found little support for this relationship.<ref name=BNA/> More recent DNA studies have confirmed a close relationship with particularly the cranes,<ref name=Livezey1998/> with the limpkin remaining as a family close to the cranes and the two being sister taxa to the trumpeters.<ref name=Fain2007/>
Although the limpkin is the only extant species in the family today, several fossils of extinct Aramidae are known from across the Americas. The earliest known species, Aramus paludigrus, is dated to the middle Miocene of Colombia.<ref name=Rasmussen1997/> An Oligocene fossil from Europe, Parvigrus pohli (family Parvigruidae), has been described as a mosaic of the features shared by the limpkins and the cranes. It shares many morphological features with the cranes and limpkins, but also was much smaller than either group, and was more rail-like in its proportions. In the paper describing the fossil, Gerald Mayr suggested that it was similar to the stem species of the grues (the cranes and limpkins), and that the limpkins evolved massively long bills as a result of the specialisation to feeding on snails. In contrast, the cranes evolved into long-legged forms to walk and probe on open grasslands.<ref name=Mayr2005/>
SubspeciesEdit
Between 1856 and 1934, the limpkin was treated as two species, one in South America (Aramus guarauna) and the other found in Central America, the Caribbean, and Florida (Aramus pictus). Today, it is treated as a single species with four subspecies. Along with the nominate subspecies A. g. guarauna, A. g. dolosus, A. g. elucus (both J. L. Peters, 1925), and A. g. pictus (F. A. A. Meyer, 1794) are recognized. The difference between the subspecies are related to slight differences in size and plumage.<ref name="hbwfamily"/>
- Aramus guarauna guarauna - South America (except the arid west coast, the Andes and extreme south)
- Aramus guarauna pictus - Florida, Georgia, The Bahamas, Cuba and Jamaica
- Aramus guarauna elucus - Hispaniola and (formerly) Puerto Rico
- Aramus guarauna dolosus - Southwestern Mexico to Panama
DescriptionEdit
The limpkin is a somewhat large bird, Template:Convert long, with a wingspan of Template:Convert. Body mass ranges from Template:Convert, averaging Template:Convert.<ref name=CRC/> The males are slightly larger than the females in size, but no difference in plumage is seen.<ref name =BNA/> Its plumage is drab—dark brown with an olive luster above. The feathers of the head, neck, wing coverts, and much of the back and underparts (except the rear) are marked with white, making the body look streaked and the head and neck light gray. It has long, dark-gray legs and a long neck. Its bill is long, heavy, and downcurved, yellowish bill with a darker tip.<ref name=H&W/><ref name=Sibley/> The bill is slightly open near but not at the end to give it a tweezers-like action in removing snails from their shells, and in many individuals the tip curves slightly to the right, like the apple snails' shells.<ref name=CLO/> The white markings are slightly less conspicuous in first-year birds.<ref name=Sibley/> Its wings are broad and rounded and its tail is short.<ref name=Firefly/> It is often confused with the immature American white ibis.
This bird is easier to hear than see. Its common vocalization is a loud wild wail or scream<ref name=H&W/><ref name=Firefly/> with some rattling quality, represented as "kwEEEeeer or klAAAar."<ref name=Sibley/> This call is most often given at night<ref name=Firefly/> and at dawn and dusk.<ref name=H&W/> Other calls include "wooden clicking",<ref name=Sibley/> clucks,<ref name=Firefly/> and in alarm, a "piercing bihk, bihk...".<ref name=H&W/>
- Limpkin-2.jpg
Limpkin performing a wing-stretch
- Aramus guarauna-takes off.jpg
Taking off
Distribution and habitatEdit
The limpkin occurs from peninsular Florida (and the Okefenokee Swamp in southern Georgia)<ref name=Peterson1947/> and southern Mexico through the Caribbean and Central America to northern Argentina. In South America, it occurs widely east of the Andes; west of them its range extends only to the Equator.<ref name=H&W/><ref name=Firefly/>
It inhabits freshwater marshes and swamps, often with tall reeds, as well as mangroves.<ref name=H&W/><ref name=Firefly/> In the Caribbean, it also inhabits dry brushland.<ref name=Firefly/> In Mexico and northern Central America, it occurs at altitudes up to Template:Convert.<ref name=H&W/> In Florida, the distribution of apple snails is the best predictor of where limpkins can be found.<ref name=BNA/>
The limpkin undertakes some localized migrations, although the extent of these is not fully understood. In some parts in the northern part of the range, females (and a few males) leave the breeding areas at the end of summer, returning at the end of winter.<ref name="hbwfamily"/> In Brazil, birds breeding in some seasonal marshes leave during the dry season and return again with the rains.<ref name=BNA/> Birds may also migrate between Florida and Cuba, as several limpkins on the Florida Keys and Dry Tortugas have been reported, but these records may also represent vagrants or postbreeding dispersal. One study in Florida using wing tags found limpkins dispersed up to Template:Convert away from the breeding site. This tendency may explain vagrant limpkins seen in other parts of the United States and at sea near the Bahamas.<ref name="hbwfamily"/>
Behavior and ecologyEdit
Limpkins are active during the day, but also forage at night. Where they are not persecuted, they are also very tame and approachable.<ref name="hbwfamily"/> Even so, they are usually found near cover.<ref name=H&W/> They are not aggressive for the most part, being unconcerned by other species and rarely fighting with members of their own species.<ref name="hbwfamily"/>
Because of their long toes, they can stand on floating water plants. They also swim well, both as adults or as newly hatched chicks, but they seldom do so.<ref name=BNA/> They fly strongly, the neck projecting forward and the legs backward,<ref name=Firefly/> the wings beating shallowly and stiffly, with a jerky upstroke, above the horizontal most of the time.<ref name=H&W/>
FeedingEdit
Limpkins forage primarily in shallow water and on floating vegetation such as water hyacinth and water lettuce.<ref name=Stevenson1994/> When wading, they seldom go deeper than having half the body underwater, and never are submerged up to the back.<ref name=BNA/> They walk slowly with a gait described as "slightly undulating" and "giving the impression of lameness or limping",<ref name=Firefly/> "high-stepping",<ref name=H&W/> or "strolling",<ref name=Sibley/> looking for food if the water is clear or probing with the bill.<ref name=CLO/><ref name=Firefly/> They do not associate with other birds in mixed-species feeding flocks, as do some other wading birds, but may forage in small groups with others of their species.<ref name=Bennetts/>
The diet of the limpkin is dominated by apple snails (Ampullariidae) of the genus Pomacea. The availability of this one mollusk has a significant effect on the local distribution of the limpkin.<ref name=Cottam/> Freshwater mussels, including Anodonta cowperiana, Villosa vibex, Elliptio strigosus, E. jayensis, and Uniomerus obesus, as well as other kinds of snails, are a secondary food sources.<ref name=BNA/> Less important prey items are insects, frogs, lizards, crustaceans (such as crayfish)<ref name="Aramus guarauna Limpkin">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and worms,<ref name=Firefly/> as well as seeds.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Aramus guarauna Limpkin"/> These prey items may be important in periods of drought or flooding when birds may be pushed into less than optimal foraging areas.<ref name=BNA/> In one site in Florida, moon snails and mussels were the most important prey items.<ref name=BNA/> Two studies, both in Florida, have looked at the percentage composition of the diet of limpkins. One, looking at stomach contents, found 70% Pomacea apple snails, 3% Campeloma, and 27% unidentified mollusc, probably Pomacea.<ref name=BNA/><ref name=Cottam/>
When a limpkin finds an apple snail, it carries it to land or very shallow water and places it in mud, the opening facing up. It deftly removes the operculum or "lid" and extracts the snail,<ref name=Firefly/> seldom breaking the shell. The extraction takes 10 to 20 seconds.<ref name=CLO/> The orange-yellow yolk gland of female snails is usually shaken loose and not eaten.<ref name=BNA/> It often leaves piles of empty shells at favored spots.<ref name=Firefly/>
Reproduction and breedingEdit
Males have exclusive territories, which can vary in size from Template:Convert. In large, uniform swamps, nesting territories can often be clumped together, in the form of large colonies. These are vigorously defended, with males flying to the territory edges to challenge intruders and passing limpkins being chased out of the territory. Territorial displays between males at boundaries include ritualized charging and wing-flapping. Females may also participate in territorial defense, but usually only against other females or juveniles. Territories may be maintained year-round or abandoned temporarily during the nonbreeding season, usually due to lack of food.<ref name=BNA/>
Limpkins may be either monogamous, with females joining a male's territory, or serially polyandrous, with two or more females joining a male. With the monogamous pairs, banding studies have shown that a small number of pairs reform the following year (four out of 18 pairs).<ref name=BNA/>
Nests may be built in a wide variety of places – on the ground, in dense floating vegetation,<ref name=Nicholson/> in bushes, or at any height in trees. They are bulky structures of rushes, sticks, or other materials. Nest building is undertaken by the male initially, which constructs the nest in his territory prior to pair-bond formation. Unpaired females visit a number of territories before settling on a male with which to breed. Males may initially challenge and fight off prospective mates, and may not accept first-year females as mates. Pair-bond formation may take a few weeks. Courtship feeding is part of the bonding process, where males catch and process a snail and then feed it to the female.<ref name=BNA/>
The clutch consists of three to eight eggs, with five to seven being typical and averaging 5.5,<ref name=BNA/> which measure Template:Convert. The egg color is highly variable. Their background color ranges from gray-white through buff to deep olive, and they are marked with light-brown and sometimes purplish-gray blotches and speckles. The eggs are laid daily until the clutch is complete, and incubation is usually delayed until the clutch is completed. Both parents incubate the eggs during the day, but only the female incubates at night. The shift length is variable, but the male incubates for longer during the day. The male remains territorial during incubation, and leaves the clutch to chase off intruders; if this happens, the female returns quickly to the eggs. The incubation period is about 27 days, and all the eggs hatch within 24 hours of each other.<ref name=BNA/>
The young hatch covered with down, capable of walking, running, and swimming. They follow their parents to a platform of aquatic vegetation, where they are brooded. They are fed by both parents; they reach adult size at 7 weeks and leave their parents at about 16 weeks.<ref name=CLO/><ref name=Firefly/>
EcologyEdit
Limpkins are reported to be attacked and eaten by American alligators. Also, adults with serious foot and leg injuries have been reported, suggesting they may have been attacked by turtles while standing on floating vegetation. Their nests are apparently preyed upon by snakes, raccoons, crows, and muskrats.<ref name=BNA/> Foraging adults may in times of drought be victims of kleptoparasitism by snail kites,<ref name=Miller1985/> and the attempted theft of apple snails caught by limpkins has also been observed in boat-tailed grackles.<ref name=Bennetts/>
Limpkins in Florida were examined for parasites, which included trematodes, nematodes, and biting lice. Two biting lice species were found, Laemobothrion cubense and Rallicola funebris. The trematode Prionosoma serratum was found in the intestines of some birds; this species may enter the bird after first infecting apple snails (this has been shown to be the route of infection for a closely related trematode to infect snail kites). Nematodes Amidostomum acutum and Strongyloides spp. are also ingested and live in the gut.<ref name="Florida parasite"/>
Relationship with humansEdit
Many of the limpkin's names across its range are onomatopoeic and reflect the bird's call; for example, carau in Argentina, carrao in Venezuela, and guareáo in Cuba. The species also has a range of common names that refer to its call, for example lamenting bird, or to its supposed gait, crippled bird. The limpkin does not feature much in folklore, although in the Amazon people believe that when the limpkin starts to call, the river will not rise any more.<ref name="hbwfamily"/> Its call has been used for jungle sound effects in Tarzan films<ref name=Phillips/> and for the hippogriff in the film Harry Potter and the Prisoner of Azkaban.<ref name=Ramanujan2005/>
ReferencesEdit
External linksEdit
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- Limpkin Bird Sound at Florida Museum of Natural History
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