The Javan hawk-eagle: misconceptions about rareness and threat

Balen, S.B. van; Nijman, Vincent; Prins, Herbert H. T.

doi:10.1016/s0006-3207(00)00092-6

Cited by 23 publications

(25 citation statements)

References 21 publications

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“…Although a wealth of primatological research has been conducted in Asia (see reviews in Campbell et al 2007) as indicated by Janson (1998) the most direct method to explore the impact of predation on primate populations is to conduct studies of the predators themselves that would reveal the prey profiles for each predator. Spizaetus hawkeagles are notoriously difficult to observe in the rainforest, and may be rare (Nijman 2004b;van Balen et al 2000). Thiollay (1985) estimated that on average he observed only one raptor day -1 while walking slowly inside the rainforest.…”

Section: Discussionmentioning

confidence: 99%

Spizaetus hawk-eagles as predators of arboreal colobines

Fam

Nijman

2011

Primates

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The predation pressure put on primates by diurnal birds of prey differs greatly between continents. Africa and South America have specialist raptors (e.g. crowned hawk-eagle Stephanoaetus coronatus and harpy eagle Harpia harpyja) whereas in Asia the only such specialist's (Philippine eagle Pithecophaga jefferyi) distribution is largely allopatric with primates. The almost universal absence of polyspecific groups in Asia (common in Africa and South America) may indicate reduced predation pressure. As such there is almost no information on predation pressures on primates in Asia by raptors. Here we report successful predation of a juvenile banded langur Presbytis femoralis (~2 kg) by a changeable hawk-eagle Spizaetus cirrhatus. The troop that was attacked displayed no signs of being alarmed, and no calls were made before the event. We argue that in insular Southeast Asia, especially, large Spizaetus hawk-eagles (~2 kg) are significant predators of arboreal colobines. Using data on the relative size of sympatric Spizaetus hawk-eagles and colobines we make predictions on where geographically we can expect the highest predation pressure (Thai-Malay Peninsula) and which colobines are least (Nasalis larvatus, Trachypithecus auratus, P. thomasi) and most (P. femoralis, T. cristatus) affected.

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Section: Discussionmentioning

confidence: 99%

Spizaetus hawk-eagles as predators of arboreal colobines

Fam

Nijman

2011

Primates

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“…With the wide size and different land use, not all patches have forest cover dominated by forests as habitat need for nesting. Patch 11 and patch 18 have large availability of forests and adjacent landscape mosaics in the vicinity of agricultural areas that can serve as secondary habitats [24]. Yet, this condition is different from that occurred in patches 13 and 16.…”

Section: Core Patchmentioning

confidence: 99%

“…The Javan HawkEagle is a raptor that relies heavily on natural forests to build its nest [24]. With the wide size and different land use, not all patches have forest cover dominated by forests as habitat need for nesting.…”

Section: Core Patchmentioning

confidence: 99%

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GIS-based approach for quantifying landscape connectivity of Javan Hawk-Eagle habitat

Nurfatimah

Syartinilia

Mulyani

2018

IOP Conf. Ser.: Earth Environ. Sci.

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Abstract. Javan Hawk-Eagle (Nisaetus bartelsi; JHE) is a law-protected endemic raptor which currently faced the decreased in number and size of habitat patches that will lead to patch isolation and species extinction. This study assessed the degree of connectivity between remnant habitat patches in central part of Java by utilizing Conefor Sensinode software as an additional tool for ArcGIS. The connectivity index was determined by three fractions which are infra, flux and connector. Using connectivity indices successfully identified 4 patches as core habitat, 9 patches as stepping-stone habitat and 6 patches as isolated habitat were derived from those connectivity indices. Those patches then being validated with land cover map derived from Landsat 8 of August 2014. 36% of core habitat covered by natural forest, meanwhile stepping stone habitat has 55% natural forest and isolated habitat covered by 59% natural forest. Isolated patches were caused by zero connectivity (PCcon = 0) and the patch size which too small to support viable JHE population. Yet, the condition of natural forest and the surrounding matrix landscape in isolated patches actually support the habitat need. Thus, it is very important to conduct the right conservation management system based on the condition of each patches.

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“…Therefore, aggregations of smaller forest areas may be considered as composites cemented by mature plantations and certain types of agricultural land . The presence of Javan Hawk-eagle in small long-isolated forest patches (van Balen et al 2000) which on their own may not be large enough to support a viable eagle population, suggests that the surrounding (non-forest) habitat acts to increase the effective size of the small forest areas. Moreover, vast stands of plantations may increase connectivity, i.e.…”

Section: Introductionmentioning

confidence: 99%

Wandering Stars: Alterskorrelierte Habitatnutzung und Ausbreitung des Javahaubenadlers (Spizaetus bartelsi)

Nijman

Balen²

2003

J Ornithol

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SummaryNatal dispersal and philopatry have rarely been studied in tropical forest raptors. Especially with respect to endangered species with fragmented distributions more knowledge of dispersal and age-related habitat preferences is needed for proper management. We conducted an island-wide study on age-related habitat preferences of the endangered Javan Hawk-eagle (Spizaetus bartelsi), Indonesia's national bird. The Javan Hawk-eagle is a true forest eagle, but is occasionally observed in non-forested areas. On the basis of 95 visual encounters in 50 localities in the period 1980-2002, we established that there were no agerelated differences in geographical, altitudinal or climatic distribution. In habitat preferences, however, juveniles and immatures are proportionally more often recorded in open and disturbed habitats than adults, which seem to have a greater preference for evergreen forest. These results indicate that the prime habitat for adult Javan Hawk-eagles is evergreen forest and to a lesser degree secondary forest, with juveniles dispersing out of their natal territory into different habitat types, including seemingly unsuitable types. In their habitat choice, imrnatures tend to be more similar to adults than to juveniles, which is an indication that their dispersal takes place into habitats that are more suitable for establishing a breeding territory.Key words: Falconiformes, Spizaetus bartelsi, habitat preferences, philopatry, raptors. often zeigte keine altersbedingten Unterschiede in der geographischen, h6henbedingten oder klimatischen Verbreitung, wies aber dagegen auf eine unterschiedliche Habitatwahl juveniler und subadulter Adler bin. Diese wurden signifikant h~iufiger in offenen und degradierten Gebieten beobachtet, wShrend die adulten Tiere eine st~irkere Pr~iferenz ftir geschlossene Regenwaldgebiete aufwiesen. Die Fortpflanzung des Javaadlers findet meist im Regenwald statt, und die frisch ansgeflogen Tiere zeigen ~ihnliche Habitatvorlieben wie die Adulti. Dies best~itigt, dass der Regenwald den primSxen Lebensraum des Javaadlers darstellt und die Jungtiere sich in andere, darunter auch anscheinend weniger geeignete, Habitate ausbreiten. Die subadulten Tiere zeigen dagegen Habitatpr~iferenzen, die st~irker an die der Altv6gel erinnern als an die der Juvenilen. Dies weist m6glicherweise darauf bin, dass sie in dieser Lebensphase bereits Bereiche suchen, die als Brntterritorium geeignet sind. Zusammenfassung

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The Javan hawk-eagle: misconceptions about rareness and threat

Cited by 23 publications

References 21 publications

Spizaetus hawk-eagles as predators of arboreal colobines

Spizaetus hawk-eagles as predators of arboreal colobines

GIS-based approach for quantifying landscape connectivity of Javan Hawk-Eagle habitat

Wandering Stars: Alterskorrelierte Habitatnutzung und Ausbreitung des Javahaubenadlers (Spizaetus bartelsi)

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