Jacanas

(Jacanidae)

Class Aves

Order Charadriiformes

Suborder Charadrii

Family Jacanidae

Thumbnail description
Medium-sized waterbirds with elongated legs and extremely long toes, which they use to walk on floating aquatic plants

Size
6–23 in (15–58 cm); 1.4–9.7 oz (40–275 g)

Number of genera, species
6 genera; 8 species

Habitat
Inland lakes, ponds, and marshes with floating vegetation; also flooded farm fields and wet grassy areas

Conservation status
Not threatened

Distribution
Tropical and subtropical regions in Central America, South America, Africa, India, Australia, and Asia

Evolution and systematics

Grouped with gulls and shorebirds, jacanas belong to the same suborder (Charadrii) as similar small, long-legged birds found near water, such as sandpipers, plovers, and snipes.

Since jacanas have similarities in appearance and behavior to rails, some researchers have suggested that they are related to Gruiformes, but recent studies call this theory into question. Instead, scientists believe jacanas are more closely related to sandpipers and painted snipes. In all, eight species of jacanas are grouped within six genera.

Studies have shown the Charadriiformes separated from the Gruiformes in the late Cretaceous period. While jacanas appeared more recently, little fossil evidence has been found. A DNA analysis found two geographically distinct taxa for all six genera of jacanas, including the painted snipe. They included the New World jacana and Asian hydrophasianus in one group and the African microparra and Australian irediparra in the other. Scientists suggested this pattern resulted from the extinction of intervening African and Asian taxa.

Scientists are still studying the evolutionary reason for another unusual characteristic of jacanas: they are polyandrous (females mate with more than one male). Jacanas also exhibit sex-role reversal. Males tend the nest and care for chicks while the larger, more aggressive females defend the territory from predators. Researchers have theorized that jacanas may have evolved with this unorthodox system to compensate for a high rate of egg and chick loss, which typically is greater than 50% due to their unstable aquatic habitat and attacks by water snakes, turtles, and larger birds. If females can spend less time sitting on the nest and more time mating with multiple partners, scientists argue, they can lay more eggs and contribute to the overall success of the species.

Physical characteristics

Lesser jacanas have neotenous plumage, downy chicks, carpal spurs, cornified leading edge of radii, and frontal shields, wattles, or combs.

Of all the waterbirds, jacanas have the longest toes and claws, which can reach 4 in (10.2 cm) long in some species. Jacanas evolved with these slender feet to help them better adapt to their watery environment. They can easily skip across lily pads and other floating plants to search for food, build nests, and evade predators.

Like their close relatives the plovers, some jacanas have a metacarpal spur jutting out from the bend in their wing. They use these sharp, bony weapons to threaten rivals and predators during fights.

Also called "lily trotters," the most dramatic jacana feature is oversized feet, which help them to balance on lily pads. They sometimes appear to walk on water, which is why the jacana is also called the "Jesus bird" in some areas.

Jacanas are medium-sized birds with long, slender necks. The largest species is the pheasant-tailed jacana (Hydrophasianus chirurgus). This foot-long bird grows resplendent tail feathers, which can reach 20 in (50.8 cm) in length. The smallest species in the family is the 6 in (15.2 cm) lesser jacana (Microparra capensis). Female jacanas are 60% heavier than males.

Jacanas appear rather plain, with black or reddish-brown plumage, but when they spread their wings they are very dramatic birds. Jacanas often flash their contrasting flight feathers to startle predators. The flight feathers may be contrastingly colored, depending on the species. In the northern jacana, for example, wing tips are bright yellow. Most jacanas also have a colorful frontal shield. Male and female jacanas have the same coloration. With the exception of the northern and lesser species, jacanas lose all of their flight feathers concurrently during the annual molt, making them temporarily flightless.

Young jacanas have brown plumage with white underparts. They assume adult characteristics after about a year. Newly fledged jacanas have a smaller forehead shield.

Jacanas may not have melodious calls, but they are very vocal, especially when breeding and caring for young. Ornithologists have described the northern and pheasant-tailed jacanas' calls as a cat-like mewing sound, which can turn into a more strident cry during times of stress or crisis. Males and females give the same calls, but males have higher voices and vocalize more often.

Distribution

Jacanas are widely distributed across the tropical areas of the world, including Central and South America, Africa, Asia, Australia, and Madagascar.

The American representative of this family is the northern jacana (Jacana spinosa), whose popular and scientific names are derived from a Tupi Indian expression. There are nine subspecies of Jacana spinosa, distributed from Mexico to Argentina.

The African jacana, or lily trotter (Actophilornis africanus) and the lesser jacana (Microparra capensis) are found south of the Sahara in Africa, along with the Malagasy jacana (Actophilornis albinucha), which is close to the African jacana. There are two species in India; one of these, the pheasant-tailed jacana (Hydrophasianus chirurgus), is conspicuous because of a long tail, wings that are dazzling white in flight, and golden-yellow neckband. Its breeding area reaches as far as China and Afghanistan. The comb-crested jacana, (Irediparra gallinacea), has three subspecies with a distribution from Borneo to Australia.

Habitat

Water is the key requirement for jacana habitat. They also need thick mats of floating aquatic vegetation for shelter, nesting material, and food supplies. Freshwater marshes are the preferred habitat, although they have been known to feed in flooded pastures, rice fields, ephemeral ponds, and sometimes in emergent marsh vegetation.

Jacanas can be found from sea level to 8,000 feet (2,438m). They prefer lowland ponds and marshes with an unobstructed view of the water. Jacanas rarely, if ever, occur in forested areas.

Behavior

From the time they hatch, jacanas can swim and dive. They use this ability to escape predators when they are young and during the molting period when the adult bird loses its flight feathers.

Despite their size, jacanas are very inconspicuous birds. Adults and chicks are adept at hiding in aquatic vegetation.

Jacanas usually are found in pairs, grouped in clusters of territories. Each female mates with and defends the territory of one to four or more males at a time, and each territory can be as large as half a football field. For example, territories for bronze-wing jacanas range in size from 40–347 acres (16.5–139 hectares). The northern jacana's territory ranges in size from 0.25–1.7 acres (0.1–0.69 hectares). Unattached female rivals often will approach a mated pair and challenge the dominant female in an attempt to take over her territory. If the rival female is successful, she may kill chicks produced by the previous pair so that she can begin mating with the male.

Male and female partners work together to defend their territory. If a predator enters their boundaries the male, who sits on the nest, will call to the female. The female will come close and, if necessary, physically attack an intruder or rival female. The conflict usually begins with a territorial display. The female spreads her feathers, with wings slightly down and forward, to display sharp wing spurs. If the predator comes closer, the female may strike with wing spurs or jab with the bill.

Males have a complex range of calls to signal danger to their offspring. When they hear these sounds, chicks move closer to the male. He gathers them under his wings to protect them, or encourages them to hide under water plants. Many juvenile jacanas have evolved with special breathing holes at the end of their bills. This allows them to dive underwater to safety, with only the tips of their bills emerging from the surface. When the male signals that it is safe, they come out of hiding. Observers have noted this "snorkeling" behavior in young wattled jacanas, northern jacanas, and pheasant-tailed jacanas. At other times, the male may fake a broken wing to lure a predator away from chicks.

In rare cases, jacanas will develop a symbiotic relationship with other animals in their environment. For example, a researcher in the Congo observed an African jacana standing on a hippopotamus, grooming its back. Jacanas also clean ticks from capybaras.

Jacanas generally do not migrate, but the pheasant-tailed jacana is a partial migrant. Jacanas remain in the same place as long as they have suitable habitat. If drought conditions cause a pond to dry up, however, they may move to an area with a better supply of aquatic plant material. When they are not breeding, jacanas may flock together by the hundreds.

Feeding ecology and diet

Jacanas' primary food source is insects, which they find by perching on floating water lily leaves with their heads down and turning leaves over with their toes. Invertebrates such as aquatic moth larvae are another source of food. They seem to prefer small, floating organisms to flying insects. Jacanas occasionally eat small fish, but this is rare.

Jacanas use their bills to forage for seeds and insects caught in the fibrous roots of water lilies. They also may run their bills along the stems of marsh grasses to collect and eat other types of seeds.

Female jacanas help build and defend the nest of offspring, but only males are responsible for feeding the chicks.

Reproductive biology

During the rainy season, when nesting material and food are in ample supply, jacanas will begin actively breeding. Unlike other bird families, jacana females dominate the process.

Once a female initiates courtship, a male starts building several nest sites. The more aggressive female will choose which nest to use for laying eggs, or she may choose an entirely different site in the male's territory and the male will have to build a new nest. Jacana nests are not elaborate; they consist of water lily leaves and other plant material heaped on top of a thick mat of floating vegetation.

Courtship begins when the female approaches an eligible male. The two birds may flash their wings and call to each other. As a sign that a pheasant-tailed jacana female is ready to mate, she may grow larger and develop more distinctive tail feathers. When a female takes over a rival female's territory, she often displays her dominance by pecking at the male's neck and back. The male signals submissiveness by crouching and lowering his head.

Because females are busy guarding harems of four or five males, the males sit on the nest and incubate eggs. Studies

have shown that female jacanas, who mate with several partners simultaneously, often will lay eggs from several different males in one clutch. In other words, a male may spend days caring for eggs and offspring that are not his own.

Female jacanas typically produce four small eggs that are glossy brown and covered with speckles. To better warm the eggs, males have evolved with incubation patches (special areas of increased circulation) on their chests. After a long incubation period of 22–28 days, chicks emerge from their shells. At first they are covered with downy plumage that has a striped camouflage design. Like their parents, they are born with extremely large feet.

In addition to incubating the eggs, males are primary care-givers. As soon as the chicks hatch, the male teaches them to forage for plants and insects while paddling around the lily pads. The male sends the chicks out to search for food, then calls them back to check on them. Ornithologist Alfred Hoffman, who studied Chinese pheasant-tailed jacanas in the 1940s, described the male jacana as a devoted father: "First he plants himself with his legs spread, then lowers his body a little by bending his legs and raising his wings slightly, and with them he protects the chicks as they snuggle up to him. Such a comforting rest period of about five to 10 minutes breaks up the strenuous wanderings in search of food."

Despite the male's vigilant parenting skills and the female's vigorous defense of boundaries, juvenile jacanas face low odds of survival. More than 50% never make it out of the nest. Of those that survive, fewer than 50% reach adulthood. In some species, such as the African jacana, the failure rate is as high as 90%. The jacana's most common predator is the purple gallinule (Porphyrula martinica, family Rallidae), which often robs eggs from the nest. Floods, water snakes, otters, and turtles also pose a threat.

Conservation status

Currently, there are no threatened species. Jacanas depend on wetlands for survival, but in many parts of the world their habitat is being drained to make way for housing and commercial development or agriculture.

In Taiwan, local conservationists took steps to create a new habitat for a group of pheasant-tailed jacanas threatened by a high-speed rail project under construction in their territory.

Some studies show that pesticides may pose a danger to jacanas. In one area, near a coffee plantation in Costa Rica, researchers noted that pesticide exposure may have caused a decrease in egg-laying activity.

Significance to humans

Jacanas are not in danger of shooting or trapping anywhere in their range. Because most jacana species are well known to local fishermen and suffer relatively little persecution, they are often tame and confiding. In much of the world they are found on artificial water bodies, often fairly close to human habitation.

Species accounts

List of Species

Northern jacana

Jacana spinosa

taxonomy

Jacana spinosa Linnaeus, 1758, western Panama. Three subspecies.

other common names

English: American jacana; French: Jacana du Mexique; German: Gelbstirn-Blatthühnchen; Spanish: Jacana Centroamericana.

physical characteristics

6.7-9 in (17–23 cm). Females are 60% heavier than males. Adults have reddish-brown plumage with contrasting greenish-yellow wing feathers and a yellow forehead shield. Juveniles are light brown and white.

distribution

Year-round resident in Mexico, from Gulf of Mexico south, including Yucutan peninsula and Cozumel, Central America, and West Indies; also occasionally appears in southern Texas, north to Austin and west of San Antonio, where it used to breed.

habitat

Marshes, ponds, and lakes with floating aquatic vegetation; also rivers, flooded pastures, and wet meadows. Breeds in both permanent and seasonal wetlands.

behavior

Males and females actively defend territories with vocal calls. Females will engage in fights with intruders.

feeding ecology and diet

Prefers a variety of aquatic plants and insects; except for water lily seeds, ingestion of plant material may be incidental.

reproductive biology

Breeds during rainy season if a permanent marshland is available. Females are polyandrous and mate with up to four males and guard their territories. Males incubate eggs and care for chicks. Males build nests of leaves and plants on floating vegetation. Females lay four glossy brown speckled eggs. Incubation is 22–28 days. Breeding success is less than 50%.

conservation status

Not threatened.

significance to humans

None known.

Pheasant-tailed jacana

Hydrophasianus chirurgus

taxonomy

Chirurgus Scopoli, 1786, Luzon, Philippines. Monotypic.

other common names

English: Chinese water pheasant; French: Jacana àlongue queue; German: Wasserfasan; Spanish: Jacana Colilarga.

physical characteristics

11–12.2 in (28–31 cm); 4.8–8 oz (126–231 g). Largest species in the jacana family. Dark plumage with contrasting white wing tips and yellow neckband. Long, dramatic tail feathers in breeding male.

distribution

Pakistan, India, Nepal, Sri Lanka, Myanmar to southeast China, to southeast Asia, Java, and the Philippines.

habitat

Marshes, ponds, and lakes with floating aquatic vegetation. Uses emergent vegetation more in winter.

behavior

Uses elongated toes to walk on floating vegetation; only flies short distances. Spends much of its time sunning, preening, and foraging for food when not defending its nest.

feeding ecology and diet

Prefers insects and invertebrates.

reproductive biology

Breeds during rainy season. Females are polyandrous and mate with up to four males and guard their territories. Males incubate eggs and care for chicks. Males build nests of leaves and plants on floating vegetation. Females lay four glossy brown speckled eggs. Incubation is 22–28 days. Breeding success is less than 50%.

conservation status

Some populations have been threatened in China and Taiwan by habitat loss due to drained wetlands and high-speed rail projects.

significance to humans

None known.

Lesser jacana

Microparra capensis

taxonomy

Parra capensis Smith, 1839, Algoa Bay, South Africa. Monotypic.

other common names

English: Lesser African jacana, lesser lily trotter; French: Jacana nain; German: Zwergblatthühnchen; Spanish: Jacana Chica.

physical characteristics

6 in (15 cm); 1.4 oz (41 g). Smallest species in the jacana family. Brown plumage with white underparts. Adults resemble juveniles of other jacana species.

distribution

Tropical Africa, including parts of Mali, Sudan, Ethiopia, Uganda, Kenya, Zambia, Zimbabwe, Mozambique, South Africa, Angola, and Namibia.

habitat

Marshes, ponds, and lakes with floating aquatic vegetation. Also shallow water, often in emergent vegetation (sparse sedge and grass).

behavior

Males and females actively defend territories with vocal calls. Females will engage in fights with intruders.

feeding ecology and diet

Primarily insects. Swims like a phalarope.

reproductive biology

This is the only monogamous species, with both males and females sharing equally in nest incubation and caring for chicks.

conservation status

Not threatened.

significance to humans

None known.

African jacana

Actophilornis africanus

taxonomy

Parra africana Gmelin, 1789, Ethiopia. Monotypic.

other common names

English: Lily trotter; French: Jacana àpoitrine dorée; German: Blaustim-blatthühnchen; Spanish: Jacana Africana.

physical characteristics

9–12.2 in (23–31 cm); 4–9 oz (137–261 g). Brown with white and black areas. Blue forehead shield.

distribution

Tropical Africa, including wetlands of sub-Saharan Africa. Rarely found in forests or dry areas.

habitat

Marshes, ponds, and lakes with floating aquatic vegetation, including both permanent and seasonal sites. Also uses tall vegetation near shore for shelter.

behavior

Males and females actively defend territories with vocal calls. Females will engage in fights with intruders.

feeding ecology and diet

Eats a wide range of aquatic plant seeds and invertebrates.

reproductive biology

Breeds during rainy season. Females are polyandrous mate with up to four males and guard their territories. Males incubate eggs and care for chicks. Males build nests of leaves and plants on floating vegetation. Females lay four glossy brown, speckled eggs. Incubation is 22–28 days. Breeding success is less than 50%.

conservation status

Not threatened.

significance to humans

None known.

Resources

Books

Hayman, P., J. Marchant, and T. Prater. Shorebirds: An Identification Guide to the Waders of the World. New York: Houghton Mifflin Co., 1991.

Jenni, D. A., "Family Jacanidae (Jacanas)." In Handbook of the Birds of the World. Vol. 3, Hoatzin to Auks, edited by J. del Hoyo, A. Elliott, and J. Sargatal. Barcelona: Lynx Edicions, 1996.

MacKinnon, John, and Karen Phillips. Field Guide to the Birds of China. Oxford: Oxford University Press. 2000.

Marchant, S., and P. J. Higgins, eds. The Handbook of Australian, New Zealand and Antarctic Birds. Oxford: Oxford University Press, 1999.

Urban, Emil K., C. H. Fry, and S. Keith, eds. The Birds of Africa. Vol. 2. London: Academic Press, 1986.

Van Perlo, B. Birds of Southern Africa. New Jersey: Princeton University Press, 2001.

Periodicals

Jenni, Donald A. and T. R. Mace. "Northern Jacana." The Birds of North America no. 467 (1999).

Line, Les. "A Male's Work is Never Done." International Wildlife 30, no. 4 (July/August 2000): 28–35.

Wiesner, Pat. "A Strong Case of Role Reversal." BioScience 42, no. 4 (April 1992): 327.

Organizations

Neotropical Bird Club. c/o The Lodge, Sandy, Bedfordshire SG19 2DL United Kingdom. E-mail: secretary @neotropicalbirdclub.org Web site: <http://www.neotropicalbirdclub.org>

Melissa Knopper