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Jabiru mycteriajabiru

By Andrew McKinley

Geographic Range

Jabiru are found in the Western Hemisphere, as far north as Mexico and as far south as Argentina. They are most common found in wetland regions of Brazil and Paraguay. Jabiru have been spotted in Argentina, Belize, Bolivia, Brazil, Columbia, Costa Rica, Ecuador, El Salvador, French Guiana, Grenada, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, Uruguay, and Venezuela, with rare sightings as far north as Texas. (UNEP-WCMC, 2006; Wikipedia, 2006)

Habitat

Jabiru are found near rivers and ponds, usually in large groups. They prefer open wetlands, especially flooded savannas. They are also seen in freshwater marshes and open country that is near water. These birds usually build their nests atop tall trees. (Belize Zoo, 2006; Grosset, 2005; Wikipedia, 2006)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Jabiru can grow as tall as 1.15 m and weigh as much as 8 kg. Their wingspan averages 2.6 m. The beak is upturned, black, and broad, and can extend to 30 cm. The plumage is white, the skin on the head and neck are featherless and black. On the top of the head there is a silver tuft of hair. There is a 75 mm band of skin around the lower portion of the neck. When jabiru are inactive, the band is a deep pink. When they are irritated, it turns a deep scarlet color. Jabiru also have a featherless red pouch at the base of the neck. Both genders have dark brown irises and black legs and feet. An oval of pink skin is located just above the sternum, but is only visible when the bird is erect just before take-off. Males are noticeably larger than females and have a larger and straighter bill. (Grosset, 2005; Kahl, 1971)

  • Sexual Dimorphism
  • male larger
  • Range mass
    8000 (high) g
    281.94 (high) oz
  • Range length
    1.15 (high) m
    3.77 (high) ft
  • Average wingspan
    2.6 m
    8.53 ft

Reproduction

In breeding pairs, wing-flapping exhibits are believed to be a form of courtship behavior. During courtship, males establish themselves at a nest site. A female then approaches a male until he accepts her presence. Females are most often rejected. During copulation, males step onto a female's back from the side, hooking his toes over her shoulders and bending his legs for contact. The female opens her wings while the male flaps his slowly for balance. The male shakes his head and clatters his bill alongside the female's bill throughout copulation. Male and female jabiru stay together for at least one breeding season, possibly staying together through multiple breeding seasons. (Kahl, 1973)

Jabiru begin gathering to mate near the end of the rainy season. Most breeding occurs from December to May. Nests are usually located within 1 km of other jabiru nests. Jabiru nests are found 15-30 m above ground in isolated, tall trees. These trees are usually near riparian forests or wetlands. Nests are often deeper than they are wide, they can be up to 1 m wide and 1.8 m deep. Nests are usually made of sticks and woody debris. The average clutch size is around 3 (range 2 to 5) eggs with an average hatching success of 44%. When nestlings are four weeks old, the parents start leaving them by themselves for more extended periods of time. Young birds fledge around 110 days after hatching, although they remain dependent on their parents. Jabiru pairs spend six to seven months a year involving themselves in reproductive tasks. Because of this long length of time spent breeding, pairs have difficulty breeding in successive years. Less than half of active pairs in one season are active the next season. Only 25% of successful pairs are successful the next season. (Barnhill, et al., 2005)

  • Breeding interval
    About half of adult jabirus mate each year, most jabiru mate every other year.
  • Breeding season
    Breeding occurs from December to May.
  • Range eggs per season
    2 to 5
  • Average eggs per season
    3.14
  • Range time to hatching
    1 to 3 months
  • Average fledging age
    100 days

Both males and females are involved in nest building, incubation, and care of the young. During incubation and the nestling stage, one parent watches over the nest while the other forages. The pairs stay in isolated breeding areas until the nestlings fledge. They exhibit strong territoriality near their nest and feeding areas. (Barnhill, et al., 2005; Kahl, 1971)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

Lifespan/Longevity

Jabiru, like most storks, have an average lifespan of about 30 years, although some have been known to live past the age of 40. (San Diego Zoo, 2006)

Behavior

Jabiru are active during the day and are social, being found in groups in both breeding and non-breeding seasons. Jabiru do not migrate, although they do move within a large range throughout the year, seeking optimal foraging areas. During breeding season mated pairs may separate themselves from large groups, but nests are found near other nesting jabiru. Jabiru patrol wetlands with long wing beats, usually in flocks. These birds usually needs two to three jumps before they can take flight. In flight, jabiru carry their necks extended with a bulge formed by the loose throat skin. The flapping is relatively slow, about 180 flaps per minute. They follow every 5-8 flaps with a short period of gliding. During warm periods of the day they may glide on thermal air currents. They walk slowly and methodically, taking under a step per second covering less than one meter each. When pursuing prey, they occasionally use a rapid jog. When jabiru perceive a threat, they stand erect and tall, with the neck extended and may snap their bills at the threat. (Barnhill, et al., 2005; Kahl, 1971)

Home Range

There are no estimates of jabiru home range in the literature.

Communication and Perception

All jabiru have a greeting display. In this display, they face each other in their nests, holding their necks erect and heads high. They clatter their bills loudly and rapidly while waving their necks from sided to side and moving their heads up and down. The presence of an inflatable throat sac also indicates to other birds when they are excited. There is undoubtedly communication that occurs among parents and young, but this has not been well documented. Jabiru are not highly vocal. (Slikas, 1998)

Food Habits

Jabiru consume large amounts of fish, mollusks, insects, and amphibians. They may also eat reptiles and small mammals. During dry seasons, they have been known to eat carrion and dead fish. They feed in flocks and usually forage by wading in shallow water. They detect prey more through tactile sensation than vision. They feed by holding their open bill at a 45 degree angle to the water. When prey is contacted, they close their bill, draw it out of the water, and throw their head back to swallow. (Kahl, 1971; Morgan, 2005; Wikipedia, 2006)

  • Animal Foods
  • mammals
  • amphibians
  • reptiles
  • fish
  • carrion
  • mollusks

Predation

Other jabiru and wood storks (Mycteria americana) have been known to attack jabiru nests. Humans are the primary predators of jabiru. Before jabiru were protected nestlings were hunted for meat. Jabiru are large birds that can effectively defend themselves and their young when confronted by most predators. (Barnhill, et al., 2005)

Ecosystem Roles

Jabiru have been known to eat dead fish and carrion, effectively preventing spread and development of disease and improving the quality of isolated bodies of water after droughts or fish die-offs. They also impact populations of preferred prey, such as small fish, mollusks, and amphibians. (Wikipedia, 2006)

Economic Importance for Humans: Positive

Before jabiru were protected they were hunted for their meat and feathers. Jabiru are important members of healthy ecosystems, drawing bird enthusiasts to natural areas. (Barnhill, et al., 2005)

  • Positive Impacts
  • food
  • body parts are source of valuable material
  • ecotourism

Economic Importance for Humans: Negative

There are no negative impacts of jabiru on humans.

Conservation Status

Jabiru gained protected status in Belize in 1973. Since then, there numbers in that area have slowly risen. They have been granted protected status by the U.S. Migratory Bird Act. Jabiru are widespread but not abundant in any area. They are considered a species of least concern by the IUCN, an improvement from a status of near-threatened in 1988. (Barnhill, et al., 2005)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Andrew McKinley (author), University of Notre Dame, Karen Powers (editor, instructor), Radford University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

molluscivore

eats mollusks, members of Phylum Mollusca

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nomadic

generally wanders from place to place, usually within a well-defined range.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

piscivore

an animal that mainly eats fish

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Barnhill, R., D. Weyer, W. Young, K. Smith, D. James. 2005. Breeding Biology of Jabirus in Belize. The Wilson Bulletin, 117: 142-153.

Belize Zoo, 2006. "The Belize Zoo" (On-line). Jabiru Stork. Accessed April 04, 2006 at http://www.belizezoo.org/zoo/zoo/birds/jab/jab1.html.

Grosset, A. 2005. "Jabiru Mycteria" (On-line). Accessed April 06, 2006 at http://www.arthurgrosset.com/sabirds/jabiru.html.

Kahl, M. 1973. Comparative Ethology of the Ciconiidae. The Condor, 75: 19-24.

Kahl, M. 1971. Observations on the Jabiru and Maguari Storks in Argentina, 1969. The Condor, 73: 220-224.

Morgan, C. 2005. "eNature Nature Guides" (On-line). Jabiru. Accessed April 02, 2006 at http://www.enature.com/flashcard/show_flash_card.asp?recordNumber=BD0613.

San Diego Zoo, 2006. "San Diego Zoo's Animal Bytes: Stork" (On-line). Birds: Stork. Accessed April 08, 2006 at http://www.sandiegozoo.org/animalbytes/t-stork.html.

Slikas, B. 1998. Recognizing and Testing Homology of Courtship Displays in Storks. Evolution, 52: 886-888.

UNEP-WCMC, 2006. "UNEP World Conservation Monitoring Centre" (On-line). CITES Species Database. Accessed April 06, 2006 at http://www.unep-wcmc.org/index.html?http://sea.unep-wcmc.org/isdb/CITES/Taxonomy/tax-species-result.cfm?Genus=Jabiru&Species=mycteria&source=animals~main.

Wikipedia, 2006. "Jabiru" (On-line). Accessed April 06, 2006 at http://en.wikipedia.org/wiki/Jabiru.

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