Distribution and conservation of the Javan Hawk-eagleSpizaetus bartelsi

Abstract

SummaryThe Javan Hawk-eagle Spizaetus bartelsi is endemic to the island of Java. Severe habitat fragmentation and small population size, aggravated by illegal hunting have put this rainforest species on the list of threatened bird species. Intensive searching since 1986 resulted in the discovery of a large number of localities additional to the historic ones. All known locality records of Javan Hawk-eagle have been scrutinized and are listed in the present paper. Confirmed post-1980 records are from 24 forest fragments of varying sizes: 10 (including 28 discrete localities) in west, seven (including 14 discrete localities) in central and seven (including 20 discrete localities) in east Java. The configuration of available habitat in forest clusters is evaluated. The co-existence with other threatened bird taxa, and the need for further field surveys and studies of the Javan Hawk-eagle are discussed. RingkasanElang Jawa Spizaetus bartelsi adalah sejenis burung pemangsa yang endemik di Pulau Jawa. Penghuni hutan lebat ini dimasukkan ke Daftar Burung yang Terancam Punah karena populasinya yang kecil dan habitatnya yang makin sedikit. Survai-survai intensif sejak tahun 1986 menghasilkan sejumlah lokasi baru sebagai tambahan dari lokasi penemuan yang sudah diketahui sejak dahulu. Semua lokasi Elang Jawa diperiksa dan didaftarkan oleh kami. Semua lokasi pasca-1980 yang dapat kami pastikan berasal dari 24 blok hutan yang bervariasi ukurannya: 10 areal (termasuk 28 lokasi) di Jawa Barat, 7 areal (termasuk 14 lokasi) di Jawa Tengah dan 7 areal (termasuk 20 lokasi) di Jawa Timur. Pengelompokan dan penyusunan kantung-kantung hutan habitat Elang Jawa akan kami evaluasi. Keberadaan jenis-jenis burung lain yang terancam punah, dan perlunya survei-survei lanjutan serta studi lapangan mengenai berbagai aspek biologi Elang Jawa akan kami diskusikan.

The Javan hawk-eagle: misconceptions about rareness and threat

“…totalling 632 man-days surveying inside natural forest areas. Details can be found in SoÈ zer and Nijman (1995), Nijman et al (2000) and van Balen et al (1999b). Table 1 summarises the information on all localities where Javan Hawk-eagles were found during the surveys in 1980±1999.…”

“…The Javan hawk-eagle is largely restricted to rugged, hilly terrain, and generally we encountered the birds in a Based on data from van Balen et al, 1999b;see Fig. 1. b Estimated area of good forest does not necessarily equal the size of the reserve.…”

“…In the same period the Bartels family gathered a large series of museum skins in the Gede-Pangrango area, and recorded the species in a number of additional sites (Bartels, 1924;SoÈ zer and Nijman, 1995). During our studies we have recorded the species in numerous localities throughout Gede-Pangrango NP, and indeed throughout Java (van Balen et al, 1999b).…”

“…Recent surveys by the authors have added numerous new locality records (van Balen et al, 1999b). The species was even found in the central part of the island where there was believed to be a wide gap of largely non-forested area between the two sub-populations of west and east Java (Thiollay and Meyburg, 1988).…”

Habitat segregation in two congeneric hawk-eagles (Spizaetus bartelsi and S. cirrhatus) in Java, Indonesia

“…Hawk-eagles were studied during all months of the year from 1994-2000, with a total survey effort of c. 300 d. The study covered 25 isolated forest areas in Java, from its westernmost tip at Ujung Kulon to its easternmost at Baluran, in addition to numerous smaller study areas (van Balen et al 1999a). Over 80% of the survey effort was outside the established protected area network.…”