Javanese eagle (Nisaetus bartelsi) is one of the species of medium-sized eagle that is endemic in Java. This animal is considered synonymous with the symbol of the Republic of Indonesia, namely Garuda. And since 1992, this bird is designated as the mascot of Indonesia's rare animals
Identification
Medium-bodied eagle, slim, with body length between 60-70 cm (from tip of beak to tip of tail).
The head is reddish-brown (kadru), with high-prominent crest (2-4 feathers, long to 12 cm) and a yellowish brown neck (sometimes golden when exposed to sunlight). Black top with white tip; crown and black mustache, while dark brown back and wings. The whitish throat with the black line (actually stripes) stretches out in the middle. Down, toward the chest, the black streaks spread over a pale brownish yellow color, which at the bottom end again turns into a red cross-cut pattern of sawa tree until brownish over pale whitish color of abdominal hairs and feet. Feathers on the legs close the leg to close to the base of the finger. Brownish tail with four dark lines and wide transverse visible on the underside, the tip of a thin white striped tail. Females are similar in color, slightly larger.
Iris yellow or brown eyes; blackish beak; sera (meat in the base of the beak) yellowish; yellow fingers. Young birds with head, neck and lower side of the body are light-brown cinnamon, with no graffiti or lines.
When flying, the Javanese eagle is similar to a brontok eagle (Nisaetus cirrhatus) a bright form, but tends to look more brownish, with the stomach looking darker, and slightly smaller in size.
High, repetitive, klii-iiw or ii-iiiw sounds vary from one to three syllables. Or a high-pitched and fast-paced call. In a way, the sound is similar to the sound of a brontok eagle although the difference is quite clear in its tone.
Distribution, ecology and conservation
The spread of this eagle is limited in Java Island, from the western end (Ujung Kulon National Park) to the eastern end of Blambangan Purwo Peninsula. But its distribution is now limited in areas with primary forests and in forested hilllands in lowland transitions with mountains. Most are found in half of the southern hemisphere of Java Island. Presumably this bird lives to specialize on the slope area.
Javanese eagles love tropical rain forest ecosystems that are always green, in the lowlands as well as in higher places. Starting from areas near the coast such as in Ujung Kulon and Meru Betiri, up to the forests of the lower and upper mountains to a height of 2200 m and sometimes 3,000 mdpl.
In general the residence of javan eagle is difficult to achieve, though not always far from the location of human activity. Presumably this bird is very dependent on the existence of primary forest as a place of life. Although it is found that eagles use secondary forests as hunting and nesting, they are located adjacent to large primary forests.
This bird of prey hunts from its perch on the tall trees in the forest. With a swift and agile ambush various prey in the branches of trees and on the ground, such as various types of reptiles, birds like walik, punai, and even chicken. Also small to medium sized mammals such as squirrels and squirrels, bats, weasels, up to monkey children.
The egging period is recorded from January to June. The nest is a pile of high-leaved leafy branches, made on a tree branch as high as 20-30 on the ground. The eggs are one grain, which is roasted for approximately 47 days.
The nest trees are high forest tree species, such as rasamala (Altingia excelsa), pairs (Lithocarpus sundaicus), tusam (Pinus merkusii), puspa (Schima wallichii), and ki sireum (Eugenia clavimyrtus). Not always deep in the forest, there are also nests that are found only 200-300 m distance from the place of recreation.
In its habitat, the Javanese eagle spreads infrequently. So although the total area of the flight, the total number is only about 137-188 pairs of birds, or the estimated number of individuals this eagle ranged between 600-1000 tails. This small population faces a major threat to its sustainability, caused by habitat loss and exploitation of species. Illegal logging and forest conversion into agricultural land have shrunk primary forest cover in Java. In the meantime, the eagle is also constantly hunted people to be traded on the black market as a pet. Because of its scarcity, keeping this bird as its own pride, and in turn makes the price of these birds soar.
Considering the small population, its limited constraints and the high pressure it faces, IUCN's world conservation organization puts the Javanese eagle into EN (Endangered, endangered) status. Likewise, the Indonesian Government designates it as an animal protected by law.
Taxonomic note
Indeed, the existence of Javanese eagles has been known since as early as 1820, when van Hasselt and Kuhl collected two specimens of this bird from the area of Mount Salak for the Museum Leiden, the Netherlands. However, during that time until the late 19th century, the specimens of these birds are still considered a type of brontok eagle.
New in 1908, on the basis of a collection specimen made by Max Bartels of Pasir Datar, Sukabumi in 1907, a bird expert in Germany, O. Finsch, recognized him as a new taxon. He thinks of him as the kind of child of Spizaetus kelaarti, a kind of eagle in Sri Lanka. Until then in 1924, Prof. Stresemann named the new taxon with a specific epithet of bartelsi, in honor of Max Bartels above, and incorporated him as the kind of mountain eagle Spizaetus nipalensis.
Thus, the bird was later known to the world by the scientific name Spizaetus nipalensis bartelsi, until finally in 1953 D. Amadon proposed to raise his rank and put him into a separate type, Spizaetus bartelsi.
How to Live and Reproduce
Javanese eagle lives by pairing and reproducing when entering the age of 3-4 years. In addition, Javanese eagles also include monogamous animals, which only live with one partner for life.
The breeding season of Javan hawk ranged from May to September, and active nest from January to June. But in fact the Java eagle can reproduce throughout the year. But not everything can hatch, because the eggs can also be preyed on other animals or deliberately taken humans.
Threat of Extinction
Javan Hawk eagle threatened extinction not because of damage to the ecosystem. But because of egg poaching and breeding factors are also predators, the extinction rate of Javan Hawk eagles is very threatened. Although usually the nest is separated from other trees and located at an altitude of 40-50 meters, there are still hunting him.
In addition to these factors, long hatching of javan hawk eggs is also considered very long. New eggs hatch on 40-50 days after being incubated. The number of eggs produced per year is also quite low, ie only one item per 2-3 years.
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