The jacanas (sometimes referred to as Jesus birds or lily trotters) are a group of tropical waders in the family Jacanidae. They are found in the tropical regions around the world. They are noted for their elongated toes and toenails that allow them to spread out their weight while foraging on floating or semi-emergent aquatic vegetation. They are also among the rare groups of birds in which females are larger, and several species maintain harems of males in the breeding season with males solely responsible for incubating eggs and taking care of the chicks.

Etymology and pronunciation

The pronunciation of the word jacana is debated. ''Jacana'' is Linnæus'

scientific Latin Contemporary Latin is the form of the Literary Latin used since the end of the 19th century. Various kinds of contemporary Latin can be distinguished, including the use of New Latin words in taxonomy and in science generally, and the fuller e ...

spelling of the Portuguese ''jaçanã'' which in turn is derived from a

Tupi Tupi may refer to: * Tupi people of Brazil * Tupi or Tupian languages, spoken in South America ** Tupi language, an extinct Tupian language spoken by the Tupi people * Tupi oil field off the coast of Brazil * Tupi Paulista, a Brazilian municipalit ...

name of the bird, ''ñaha'nã''. The Portuguese word is pronounced approximately . As in façade,

Provençal Provençal may refer to: *Of Provence, a region of France * Provençal dialect, a dialect of the Occitan language, spoken in the southeast of France *''Provençal'', meaning the whole Occitan language *Franco-Provençal language, a distinct Roman ...

, and

araçari An aracari or araçari ( , , ) is any of the medium-sized toucans that, together with the saffron toucanet, make up the genus ''Pteroglossus''. They are brightly plumaged and have enormous, contrastingly patterned bills. These birds are resid ...

, the Ç is meant to be pronounced as an S. US dictionaries give various pronunciations: , , as well as the anglicised , which is the only pronunciation in an Australian dictionary. A British dictionary gives for the spelling "jacana" and for "jaçana".

Diversity

Eight species of extant jacana are known from six genera and four fossil species have been described from the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

of Egypt and from the Pliocene of Florida. A fossil from Miocene strata in the Czech Republic was assigned to this family, but more recent analysis disputes the placement and moves the species to the Coraciidae. Jacanas are identifiable by their elongated toes and claws which enable them to walk on floating vegetation in the shallow lakes that are their preferred habitat. They have sharp bills and rounded wings, some with carpal spurs, and many species also have wattles and frontal lappets on their foreheads. Jacanas were once placed in the family Parridae based on the genus ''Parra'' but the family name is now Jacanidae based on the type genus ''Jacana''. The family is placed within the order Charadriiformes under the suborder Scolopaci and is a sister of the Rostratulidae. They have 10 tail feathers unlike most others wader groups which have twelve. They have a rudimentary caecum. Most jacanas have five neck vertebrae with the exception of ''

Hydrophasianus chirurgus The pheasant-tailed jacana (''Hydrophasianus chirurgus'') is a jacana in the monotypic genus ''Hydrophasianus''. Like all other jacanas, they have elongated toes and nails that enable them to walk on floating vegetation in shallow lakes, their p ...

'' which has six. Jacanidae_wing_bones

In terms of

sexual size dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

, female jacanas are larger than the males but are alike in plumage. The latter, as in some other wader families like the

phalarope __NOTOC__ A phalarope is any of three living species of slender-necked shorebirds in the genus ''Phalaropus'' of the bird family Scolopacidae. Phalaropes are close relatives of the shanks and tattlers, the ''Actitis'' and Terek sandpipers, a ...

s, take responsibility for incubation and care of chicks, and most species (with the exception of the monogamous

lesser jacana The lesser jacana (''Microparra capensis'') is a species of bird in the family Jacanidae. It is monotypic within the genus ''Microparra''. It is found in Angola, Botswana, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Democrat ...

) are polyandrous. They construct relatively flimsy nests on floating vegetation, and lay eggs with dark irregular lines on their shells, providing camouflage amongst water weeds. The eggs are slightly smaller than in comparable species and it has been considered that this may be due to an evolutionary tradeoff given the larger number of clutches that are laid. Male jacanas brood eggs between the wings and the body. This wing-brooding may be assisted by a special adaptation in the wing bones with either a broadening of the radius or a widening of the gap between the radius and ulna. Young chicks may also be held under the wing and transported to safety by the parent bird in some species. Young chicks dive underwater and stay submerged with only their bill out of water. Some adult jacanas also use the same technique. African jacanas go through a simultaneous moult of their flight feathers leading to a period of flightlessness. Their moult is related to their ability to breed opportunistically based on the availability of rains. Their diet consists mainly of insects and other invertebrates picked from floating vegetation or the water's surface but plant seeds may also be eaten.

Wattled jacana The wattled jacana (''Jacana jacana'') is a wader which is a resident breeder from western Panama and Trinidad south through most of South America east of the Andes. Breeding The wattled jacana lays four black-marked brown eggs in a floating n ...

s are known to pick ticks off

capybara The capybaraAlso called capivara (in Brazil), capiguara (in Bolivia), chigüire, chigüiro, or fercho (in Colombia and Venezuela), carpincho (in Argentina, Paraguay and Uruguay) and ronsoco (in Peru). or greater capybara (''Hydrochoerus hydro ...

s. The stomach content of jacanas has been found to have plant roots, stems and algae but it is thought that this may be incidentally ingested along with their invertebrate prey. Most species have rounded wings and short tails. The flight tends to be slow and weak. Most species are sedentary, but the pheasant-tailed jacana migrates from the north of its range into peninsular India and southeast Asia.

Species

References

External links

Jacana videos
on the Internet Bird Collection {{Taxonbar, from=Q212929 Charadrii Charadriiformes Shorebirds Bird families Extant Rupelian first appearances