S. (Bas) van Balen

Breeding Biology of Javan Hawk-eagle Spizaetus bartelsi in West Java, Indonesia

Summary The Javan Hawk-eagle Spizaetus bartelsi is one of the rarest and least known birds of prey, regarded as globally endangered and confined to the last remnants of forests left on the densely populated island of Java, Indonesia. Its biology is little-known and only a few cases of breeding have been reported. Systematic observations in 1992 and 1994 of two breeding pairs in the rainforest of the Gede-Pangrango National Park, West Java, are described in this paper. In total over 100 h of observation were made and covered different stages of the breeding cycle. Clutches consisted of one egg, incubated for 47 ± 1 days predominantly by the female, to whom the male brought prey. After the egg hatched the female joined the male in hunting. The male was rarely seen on the nest as copulation and prey transfer took place mainly on nearby trees. After fledging the eaglet stayed near the nest for at least two months. A prolonged post-fledging period followed, the juvenile remaining with its parents for more than one year.

The Javan hawk-eagle: misconceptions about rareness and threat

The Javan hawk-eagle (Spizaetus bartelsi) is a threatened raptor endemic to the densely populated island of Java. Historically very little is known about its biology. Recent surveys showed that the population size has been underestimated in the past. The breeding population is estimated to be 137‐188 pairs with a total of 600‐900 birds and confirmed presence in 22 discrete forest blocks throughout Java. The eagles were present in isolated forest fragments as small as 3000 ha. Good dispersal abilities in juveniles, a niche width in habitat, which is broader than previously assumed, and rather opportunistic feeding behaviour are believed to mitigate the eAects of habitat fragmentation. The appointment of the eagle as a flagship species involves serious risks, as it appears to have put the species on the list of rare birds that are in great demand with malevolent aviculturists. # 2000 Elsevier Science Ltd. All rights reserved.

Declaration of the Javan hawk eagle Spizaetus bartelsi as Indonesia's National Rare Animal impedes conservation of the species

The endangered Javan hawk eagle Spizaetus bartelsi is threatened in part by the illegal pet trade. In 1993 the species was declared Indonesias National Rare/Precious Animal, by former President Soeharto. Trade in the species and keeping it as a pet are illegal. We consolidated data about the species in trade, as observed at bird markets, with private owners, in zoological gardens (to date the species has not been bred in captivity and those in zoos are all wild-caught that were formerly in trade) and wildlife rescue centres, involving at least 68 birds. The average price for the species at bird markets was USD 40 (n = 5). The number observed at bird markets appears to have increased over time. Furthermore, prior to its declaration as a National Rare/Precious Animal it was not considered in trade to be different from other large eagles. There are indications that individuals have been illegally exported to other parts of Asia. In the early 1990s no Javan hawk eagles were kept in zoos but it became in demand in the mid 1990s and now there are 11 in six zoos throughout Java. Law enforcement with respect to trade in eagles appears to be largely absent but nine Javan hawk eagles have been brought to a wildlife rescue centre on Java. Overall, the data suggest there was an increase in trade in Javan hawk eagles after it was declared the National Rare/Precious Animal. When a threatened species is put in the spotlight to highlight its conservation plight, this should be done with close cooperation between conservation NGOs and government organizations, with appropriate legislation and/or management plans to prevent overexploitation.

Biology, taxonomy and conservation status of the Short-tailed Green Magpie Cissa [t.] thalassina from Java

The Short-tailed Green Magpie Cissa thalassina, a member of an Asian lineage of uniquely coloured corvids, is represented by two subspecies, thalassina and jefferyi, that occur on the islands of Java and Borneo, respectively. The distinct Javan nominate form is poorly described in the literature and next to nothing is published on its biology and occurrence in the wild. We here document the biology and distribution of this taxon based on hitherto unpublished historical data and on our own fieldwork. We also analyse vocal data of jefferyi, thalassina and two other Cissa species and show that jefferyi and thalassina are well-differentiated, and that thalassina is bioacoustically more similar to another Cissa species from the Asian mainland. We also demonstrate important and significant biometric differences between jefferyi and thalassina that may reflect divergent adaptations to the environment, as well as plumage differences that may serve signalling functions. Finally, the application of a novel species delimitation test to our data suggests that jefferyi and thalassina deserve to be classified as biological species because their phenotypic divergence exceeds that found in many sympatric species. The revised taxonomic status of Javan thalassina invites a reconsideration of its threat status. Based on its restricted range, extreme rarity and threats by bird trapping and habitat destruction, we consider the Javan Green Magpie as globally Critically Endangered.

Distribution and conservation of the Javan Hawk-eagle Spizaetus bartelsi

Summary The 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.

Wandering stars: Age-related habitat use and dispersal of Javan Hawk-eagles (Spizaetus bartelsi)@@@Wandering Stars: Alterskorrelierte Habitatnutzung und Ausbreitung des Javahaubenadlers (Spizaetus bartelsi)

Natal 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), Indonesias 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 age-related 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, immatures 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. Philopatrie und die Ausbreitung von Jungtieren sind bei tropischen Raubvögeln bislangkaum untersucht, obwohl gerade für bedrohte Arten mit fragmentierten Verbreitungsgebieten ein besserer Kenntnisstand über die Ausbreitungsmuster und altersbedingte Unterschiede in den Habitatvorlieben für ein effektives Management notwendig wäre. In der Zeit zwischen 1980 und 2002 führten wir eine inselweite Studie über altersbedingte Habitatpräferenzen des Javahaubenadlers (Spizaetus bartelsi) durch. Diese Art, Indonesiens Nationalvogel, ist auf Waldgebiete spezialisiert, kann aber gelegentlich auch in unbewaldeten Gebieten beobachtet werden. Die Analyse von 95 Sichtbeobachtungen an 50 Fundorten zeigte keine altersbedingten Unterschiede in der geographischen, höhenbedingten oder klimatischen Verbreitung, wies aber dagegen auf eine unterschiedliche Habitatwahl juveniler und subadulter Adler hin. Diese wurden signifikant häufiger in offenen und degradierten Gebieten beobachtet, während die adulten Tiere eine stärkere Präferenz für geschlossene Regenwaldgebiete aufwiesen. Die Fortpflanzung des Javaadlers findet meist im Regenwald statt, und die frisch ausgeflogen Tiere zeigen ähnliche Habitatvorlieben wie die Adulti. Dies bestätigt, dass der Regenwald den primären Lebensraum des Javaadlers darstellt und die Jungtiere sich in andere, darunter auch anscheinend weniger geeignete, Habitate ausbreiten. Die subadulten Tiere zeigen dagegen Habitatpräferenzen, die stärker an die der Altvögel erinnern als an die der Juvenilen. Dies weist möglicherweise darauf hin, dass sie in dieser Lebensphase bereits Bereiche suchen, die als Brutterritorium geeignet sind.

Biology and conservation of Pink-headed Fruit-dove Ptilinopus porphyreus

Summary Pink-headed Fruit-dove Ptilinopus porphyreus is a little-known, restricted-range species, endemic to the mountains of the Indonesian islands of Sumatra, Java and Bali. In the period 1981–2002 we conducted surveys throughout its range and compiled data on its presence and absence on 32 isolated mountain complexes. The fruit-dove appeared to be restricted to 2,000 m in altitude, where, depending on the size of the mountain, it reached its lower altitudinal limit between 500 and 1,000 m. The species was found mostly in singles or as pairs but occasionally in flocks of up to 17 individuals. It occurred almost exclusively in forest, feeding on figs and small berries in the upper-canopy. We documented three cases of breeding in the wild. From captive birds it is known that a single egg is laid which is incubated for 20 days, with fledging occurring after another 15–16 days. Based on a study of 104 skins, the breeding season peak in West Java is at the beginning of the dry season. Although Pink-headed Fruit-dove is found in scattered, ever-shrinking forest blocks of mostly < 200 km2, the scarcity of recent field records is more than likely due to its inconspicuous behaviour, and a threatened status is unwarranted as yet.