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The Northern Jacana (jacana spinosa)

The northern jacana (jacana spinosa) : is a unique fancy-looking, vaguely chicken-like shore bird of fresh water in the family of jacanas. Jacanas are a group of wetland birds, which are identifiable by their elongated feet, toes and claws, which enable them to walk on floating vegetation in the marshes, lakes and ponds in tropical lowlands, locally in highlands. Walks with high-stepping gait, often on tops of floating vegetation in shallow lakes that are their preferred habitat. This species is also known as the “Jesus bird”, because it appears to walk on water. In addition, these lovely birds are also known as “lily walkers or trotters” because of their slender legs and toes that give them the gracefulness to walk on the lily pads. When it flies, the feet trail behind it while on landing, it may hold the wings high for a moment displaying off the yellow flight feathers whilst making a squawking call. Northern jacanas inhabit many types of wetlands including; marshes, ponds, and lake margins.  They occasionally favor Pond edges with abundant floating vegetation and forage in wet grassy areas and flooded fields. Northern jacanas have predators; snapping turtles, spectacled caimans, snakes and various large mammals and raptors. These graceful birds are good divers and strong flyers. Due to their smaller size, the males are more graceful than the females of the species. These unusual birds are also identified by their harsh “jik” call which progressively speeds up to a chatter.

 

Physical description

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 yellow shield on the forehead. In addition its bill has yellow patches and its forehead has a yellow wattle.  Juveniles have a white underside and a darker back, head and neck. They 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 jacana’s primary and secondary yellowish-green feathers are visible plus the yellow bony spurs on the leading edge of the wings, which it can use to defend itself and it’s young one. The greenish color of the wing feathers is produced by a pigment called zooprasinin, a copper containing organic compound something rare in birds. Young jacanas (chicks) are covered in down and have patterns of orange, brown black and some white and their whilst older chicks are grey and have brownish upper parts. The female jacanas are twice as big as the male meaning that males are found to be significantly smaller than females.

Behaviours

Northern jacanas are considered permanent residents throughout their range. However some migrations and dispersions may occur as they do colonize their newly composed or formed habitat when wetter weather patterns result in increased wetland and water extent. These birds are highly social and frequently occur in small colonies with a dominant female with 1 to 4 males. These birds are diurnal and spend much of their time walking on emergency vegetation and searching for aquatic insects and seeds. They pick food off 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 exploit this foraging habitat, as they can easily support their weight on aquatic vegetation surfaces. They also forage by walking on top of wetland vegetation, using its incredibly long toes to distribute its weight and stay on tops of wetland vegetation mass. They will sometimes forage in very shallow water or on land near the shorelines. Northern jacanas have specific home territories that they use for breeding and feeding. Female territories comprise of males 1 to 4, which they breed with. They also help to maintain the territories of the males by intervening on behalf of the resident male when there is a territorial disagreement with another male. If the female loses her territory to another female, then the newcomer will have access to the males in that territory. Purple gallinules are the most common predators of the Northern jacana offspring and eggs, they will take them out the nests when the male is away. Due to this reason, northern jacanas will attack the purple gallinules when they see them in their territories. These attacks are made up of aerial attacks and charging with wings spread on the under layer. The attacks are escorted by repeated-note calls. If threatened, jacana chicks as well as adults stay underwater for long periods with only the tip of their bill above water and can also decide to swim under water in order to avoid predators.

Reproduction

The breeding system in the northern jacanas is not usual and is an example of polyandry birds. Both males and females will defend territories against other members of the same sex. Female jacanas live in territories encompassing the territories of 1-4 males and a male forms a pair bond with a female who will keep other females out of his territory. These bonds between the males and females last throughout the year even outside breeding and can only end incase a male or female is replaced. The female maintains bonds with her mates though copulations and producing clutches for them as well as protecting their territories and defending the eggs from predators. Females mate with up to four male individuals and lay eggs as frequently as every nine days. Male jacanas may tend to be polygamous only when new females arrive but extra pair copulations are not known to occur when the female holds her territory. When the northern jacanas breed, male build platforms that are for solicitation displays, copulation and used as nests as well. The male jacana will construct a floating nest with whatever plant material he can find, he will grab vegetation and walk backwards to drop the plant part in the nest. Then he pushes against and steps on the plant parts to create a compact mount, the best nests are the ones that are the most dense and stable. A male may create several nests at different sites and the female may choose one or find a site of her own in the territory. 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 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 and 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. Four eggs are typically laid per clutch with black markings. The male typically sits on the eggs and annexes nesting material in the form of aquatic plants periodically. The male incubate the eggs whilst the female may visit the nest site occasionally to squat and shade the eggs but not incubating. The eggs hatch in around 28 days. The female may reluctantly incubate the eggs if a male doesn’t have sufficient time to forage throughout the day due to rains and cool temperatures. Males spend most their time within their territory during incubation but sometimes leave the nest unattached for long periods of time. A male executes each time an egg hatches and stands next to the nest to peer into it. The male continues to incubate the remaining eggs while brooding the hatched chicks and when all the eggs hatched, the male will dispose of the remaining egg shells.  The young leave the nest around 24 hours after hatching and will follow the male jacana to good foraging spots. Chicks are able to dive, swim and feed shortly after they hatch and the male will not feed the chicks but lead them to food. The male will brood the chicks for many weeks and as the chicks get bigger, fewer can fit under the males’ wing. Females may brood the chicks while the male is away. Territorial defense for both males and females increase when the chicks are born. Males are intolerant of intruders in their territory and make calls to the female for help for predator defense. Females respond to each every call the male makes and invests much interest in the safety of the chicks, despite having little interaction with them. The females will then provide the males with a new clutch when the chicks are 12-16 weeks old.        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; the young fledge in around 8 weeks and may stay in their natal territory for more than 12 months.

Vocalization

Northern jacanas communicate with visual displays and calls. Repeated-call notes are given in a number of situations. Notes with high amplitude, note length, and duration are used when the bird is under physical attacks or when it can’t fend off an intruding conspecific. Jacanas will emit “clustered-call notes”, which are made of individual notes clustered together when jacanas attack intruders in their territories.  The nature of the repeated note calls say a lot about the intention of the caller. They also communicate by uttering a number of notes. The males make calls also when his chicks or eggs are under threat by predators. The call notes and their patterns depend on the urgency of the threat. 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 males swing their heads laterally while the females peck at the base of the male’s neck. On addition, also during flight, the bird will be heard uttering an abrasive squawking call. Vocalizations among jacanas usually occur between mating pairs. Calls are also made when a female is away from the territory for too long or even when a male cannot find a chick.

Feeding

In feeding, the jacanas compete with birds of a similar diet like the sora. Northern jacanas feed on whatever insects they can glean off of aquatic plants and surfaces. They turn over floating plants using their bills and feet whilst searching for insects hiding on the under-surface they also nourish on flowers that are opened by purple gallinules. Occasionally adults nourish on small fish. In conclusion, northern jacanas feed on insects, snails, worms, small crabs, mollusks, seeds and ovules of water lilies.

Where to find you in Uganda

In Uganda, the pearl of Africa you can find the bird species in Mabamba swamp, Kidepo valley national park and Murchison falls national park.

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