Jacana spinosa
northern jacana

Northern jacanas (Jacana spinosa) range from Mexico to Panama, although they are sometimes seen into the southern United States. They occur mainly in coastal areas. In Mexico they are found from Tamaulipas on Gulf of California coast and Sinaloa on the Pacific coast south to western Panama. Northern jacanas are also found in the Antillean islands of Cuba, Hispaniola, Jamaica, and the West Indies. (Jenni and Mace, 1999; Kaufman, 1996)

Northern jacanas inhabit many types of wetlands including; ponds, marshes and lake margins. Pond edges with abundant floating vegetation are favored. Northern jacanas occasionally forage in wet grassy areas and flooded fields. (Jenni and Mace, 1999; Kaufman, 1996)

Northern jacanas are medium sized wading birds with long legs and extremely elongated toes. Adults are relatively dark overall; they have a black neck, head and breast. The back, undersides, and tail are dark rufous. They have a yellow bill with a white base and a yellow shield on the forehead. Juveniles are bi-colored with a white underside and a darker back, head, and neck. Juveniles have a white supercilium and white lores. Both adults and juveniles have conspicuous yellow flight feathers that are visible when they raise their wings. Northern jacanas average 241 mm in length with a wingspan averaging 508 mm. Males were found to be significantly smaller than females. A study from Costa Rica showed that females weighted 145.4g and males weighed 86.9 on average. (Jenni and Collier, 1972; Sibley, 2003)

The breeding system in northern jacanas is unusual and is an example of polyandry. Both males and females will defend territories against other members of the same sex. Females mate with up to four individual males and lay eggs as frequently as every nine days. Males may be polygamous when new females arrive. When northern jacanas breed, males build platforms that are used for solicitation displays and copulation. The platforms are then used as nests. The female or the male may solicit to each other and this behavior leads to copulation. Solicitation is done by calling or posturing and it can be initiated by the male or the female. When the female assumes a pre-copulatory position, the male may fly up 10 meters or more before flying back down, landing on her back or landing alongside and hopping on her back. The male may initiate a mating event by assuming the pre-copulatory position and the female then joins him. Most copulation attempts are unsuccessful. When they are successful, the male gives distinct calls. Solicitation and copulation occur less often once a male has eggs in his nest, but may occur again when the young are 4 to 5 weeks old. (Jenni and Collier, 1972; Sibley, 2001)

Although northern jacanas are capable of breeding all year long, they usually breed at the beginning of the rainy season. During that time, females mate with up to four males and lay eggs as frequently as every nine days. Males may be polygamous when new females arrive, but extra pair copulations are not known to occur when the female holds her territory. When northern jacanas breed, males build platforms that are used for solicitation displays and copulation. The platforms are then used as nests. As in many other members of the order Charadriiformes, four eggs are typically laid per clutch. The male typically sits on the eggs and adds nesting material in the form of aquatic plants periodically. The female may visit the nest site on occasion and shade the eggs. The eggs hatch in around 28 days. The young leave the nest around 24 hours after hatching and will follow the male to good foraging spots. Because females may have several mates, some or all of the young that he raises may not be his. The development time in northern jacanas is slow; young fledge in around 8 weeks and may stay in their natal territory for more than 12 months. (Jenni and Collier, 1972; Jenni and Mace, 1999)

In northern jacanas, males exclusively construct nests, incubate eggs, and care for the young. Females do not help to raise offspring generally, but may provide some defense against predators. Males build a nest on the platform that was used for solicitation and copulation. After the female lays eggs in the nest the male continues to build the nest by flinging material over his shoulder in the direction of the nest site. Brooding is mainly done in the morning and evening. During rainy conditions, cool temperatures and times of increased cloud cover, the amount of time spent brooding increases. The young leave the nest at about 24 hours after hatching. At that point the male leads the nestlings to good foraging sites and continues to protect them. (Betts and Jenni, 1991; Jenni and Mace, 1999; Sibley, 2001)

Little is known about lifespan in northern jacanas. One male held his territory for 6.5 years and had to be around 2 years old to have a territory in the first place. (Jenni and Mace, 1999)

Northern jacanas are highly social and frequently occur in small colonies with a dominant female and 1 to 4 males. Northern jacanas are diurnal and spend much of their time walking on emergent vegetation and searching for aquatic insects and seeds. They pick food off of the surface of plants, the surface of the water, or just below the water. Their feet are highly specialized for this foraging behavior. Their small size and large feet allow these birds to exploit this foraging habitat, as they can easily support their weight on surface aquatic vegetation. (Jenni and Collier, 1972; Kaufman, 1996)

Northern jacanas have specific home territories that they use for breeding and feeding. Male territories averaged 0.36 acres and female territories averaged 0.88 acres at one site in Costa Rica. Female territories contain between one and four males, which they breed with. Females help in maintaining the territories of the males by intervening on behalf of the resident male when there is a territorial dispute with another male. If the female loses her territory to another female, then the newcomer will have access to the males in that territory. Male territories may last considerably longer than female territories. A male in Costa Rica held a territory for 6.5 years and the ownership by females changes 10 times in the same time period. (Jenni and Collier, 1972; Jenni and Mace, 1999)

Northern jacanas communicate with visual displays and calls. Repeated-note calls are given in a wide variety of situations. Notes with high amplitude, note length, and duration are used when the bird is under physical attack or when it can't fend off an intruding conspecific. The nature of the repeated note calls say a lot about the intention of the caller. Northern jacanas also communicate by giving groups of notes. This is most often given by males when his chicks are near. Flight calls are also given. Threat displays are given by outstretching the wings and pointing them forward. Males may do a submissive display in the presence of females in which they crouch down. During the submissive display the male swings his head laterally while the female pecks at the base of his neck. (Jenni and Mace, 1999)

Northern jacanas eat whatever insects they can glean off of aquatic plant surfaces. They turn over floating plants using their feet and bills while searching for insects hiding on the under-surface (Sibley 2001).They also eat flowers that are opened by purple gallinules (Porphyrio martinica) . Adults will occasionally take small fish. In a closely related species, wattled jacanas (Jacana jacana), the diet was made up of 20% seeds, with most seeds from spikerush (Eleocharis species), and 80% invertebrates, mainly insects. (Jenni and Collier, 1972; Osborne and Bourne, 1977)

Possible predators include boa constrictors (Boa constrictor), spectacled caimans (Caiman crocodilus), snapping turtles (Chelydra serpentina) and various raptors and mammals. Purple gallinules (Porphyrio martinica) are the most common predators of northern jacana eggs and offspring, they will take them out of nests when the male is away. For this reason, northern jacanas will attack purple gallinules when they see them in their territory. Attacks consist of aerial attacks and charging with wings spread on the substrate. Attacks are accompanied by repeated-note calls. (Jenni and Mace, 1999; Stephens, 1984)

Northern jacanas are presumably important secondary consumers in the marshy habitats they inhabit. At a 2.8 hectare pond in Costa Rica between 20 and 25 jacanas were present at a given time. Given the fact that they are relatively small, endothermic animals, they presumably have a high caloric requirement. Because of this, jacanas probably control insect populations. Northern jacanas also contribute to the energetic needs of purple gallinules (Porphyrio martinica). (Jenni and Mace, 1999)

Although northern jacanas provide no direct benefits to humans, they are certainly a source of enjoyment for naturalist and birders.

There are no known adverse effects of northern jacanas on humans.

Northern jacanas appear to be common throughout most of their range, but could become vulnerable with loss of wetlands. (Kaufman, 1996)